# Circle/Radius Cutting Jig



## RickKr (Dec 30, 2018)

I've been working on making a ships ladder for my granddaugther's fort. For the hand holds, I am making templates for using a circular saw for the straight parts of the cutouts and a router for the radii at the ends and for finishing the sides and edges. The router template needs to have a large radius for the router base, to create a template radius of 3.394" which will, in theory, create a radius of 1.5" at each end of the hand holds. 

I was thrashing about trying to figure out how to make a circle cutting template for my router (Bosch 1617). I was in a woodworking store recently and saw some really cool circle cutting templates and normally I wouldn't hesitate to buy one. But, money is tighter right now than usual, so I refrained. The jigs I looked at in the store rely on using a 1/4" router bit for establishing the radius that the jig will cut. The jigs had series of radiating 1/16" holes allowing radii to be set at increments of 1/16". One reason I refrained from buying one is that I remembered I'd bought the Bosch edge/circle guide jig (RA1054) about the time I bought the router. I realized I didn't need to buy anything and digging it out when I got home proved that correct. 

The Bosch jig has a cool little circle pivot point tab for inserting a 1/4" dia. rod located either in the workpiece or by using a provided suction cup with a 1/4" pin protruding. The radius I need puts the pivot tab too close to the router base to use the suction cup, so I needed to come up with a different method. Either way, I needed a way to set the radius of the router/jig. I reasoned that a 1/4" pin securely mounted in the pivot tab could be used along with calipers and a similar 1/4" pin in the router chuck for setting the radius, subracting half the pin diameter of one of the pins. I set about making a somewhat fancy one, but I realized that a partially threaded 1/4" bolt could do the job satisfactorily. I tried it and it does, but made the fancy one anyway. 

Bolt Pivot Pin (head would need to be cut off and the shaft shortened)















Brass Pivot Pin















Bolt pivot mounted in the jig








Brass pivot mounted in the jig








Setting jig for 3.394" finished template radius.








It appears that the bolt would work every bit as well as the fancy brass pin, but I do like the brass one better. I haven't tried either one out yet and I expect to encounter some glitches, perhaps in how well the caliper does in setting the right radius. It will likely take some trial and error, sneaking up on the desired setting. Even with a bit of fiddling, if it works, I'll consider it a success. I expect to set it shy of my final desired dimension for roughing it out and then setting it for a final light pass. 

Rick


----------



## Nickp (Dec 4, 2012)

Good thinking, Rick...I assume you'll be cutting the head off the bolt and use only the shaft...?


----------



## RickKr (Dec 30, 2018)

Nickp said:


> Good thinking, Rick...I assume you'll be cutting the head off the bolt and use only the shaft...?


Thanks. If I were going to use the bolt, I would cut the head off, yes. 

But, I will use the fancy brass one that I made. The shaft that inserts into the jig tang was machined to be a snug slip fit and the shoulder created by the hex brass stock is 1/2" dia., giving a fairly positive - square mounting. I trust it a lot more than a mass produced bolt, which are typically undersize by up to 0.010". The pivot hole through the tang is 0.254". The shaft on the brass pivot pin is 0.2535". 

Rick


----------



## Biagio (Mar 2, 2013)

Thanks for the idea, Rick. It looks like with a little thought, the capability could be added on to edge guides which do not have the tab for the centre pin. Might need to invert the edge guide, in order to clear the workpiece. I am sure @JOAT could come up with something.

I would not be able to achieve the tolerances you quote, but then again I probably would not need to.


----------



## sreilly (May 22, 2018)

Hey Rick, it seems your precision is far greater than I usually aim for. Would love to see pictures of the final piece.


----------



## Nickp (Dec 4, 2012)

RickKr said:


> Thanks. If I were going to use the bolt, I would cut the head off, yes.
> 
> But, I will use the fancy brass one that I made. The shaft that inserts into the jig tang was machined to be a snug slip fit and the shoulder created by the hex brass stock is 1/2" dia., giving a fairly positive - square mounting. I trust it a lot more than a mass produced bolt, which are typically undersize by up to 0.010". The pivot hole through the tang is 0.254". The shaft on the brass pivot pin is 0.2535".
> 
> Rick



...can't get better than that...have fun...


----------



## harrysin (Jan 15, 2007)

A circle jig can be made in about an hour and cost zero, as shown in this pdf.
A more ambitious one is shown in the second pdf.


----------



## CharleyL (Feb 28, 2009)

All of the posted methods work great, even the Jasper jig that you found in the store. I have used all of them at one time or another, and they all do a good job. Adding the 1/4" pivot pin to your edge guide is yet another good, and cheap, way to cut arcs and circles. Kudos for coming up with a cheap (free) solution. 

Bobj3 modified his Jasper jig so he could use it with a router bushing some years ago and posted pictures here. I thought it made the Jasper jig even easier to use, just in case anyone is interested. A search on this site should find it easily. 

Charley


----------



## MEBCWD (Jan 14, 2012)

Rick, it looks well thought out and as some of said the precision of the tool might be greater than actually required. I do think it was prudent that you did try to hold close tolerances for the tool itself, but please don't get too picky when working with wood to try to hold very close tolerances because you will lose some of the joy woodworking gives you.


----------



## RickKr (Dec 30, 2018)

MEBCWD said:


> Rick, it looks well thought out and as some of said the precision of the tool might be greater than actually required. I do think it was prudent that you did try to hold close tolerances for the tool itself, but please don't get too picky when working with wood to try to hold very close tolerances because you will lose some of the joy woodworking gives you.


Thanks, to you and the others, who have commented about the precision being a bit much. I appreciate that it is, where working with wood is concerned. As you allowed, it may be good to have held that for the tool itself. I agree. We'll see how well that translates to actually working with wood.


----------



## hawkeye10 (Jul 28, 2015)

This is my circle cutting jig. I also use it for making economy bowls.


----------



## harrysin (Jan 15, 2007)

CharleyL said:


> All of the posted methods work great, even the Jasper jig that you found in the store. I have used all of them at one time or another, and they all do a good job. Adding the 1/4" pivot pin to your edge guide is yet another good, and cheap, way to cut arcs and circles. Kudos for coming up with a cheap (free) solution.
> 
> Bobj3 modified his Jasper jig so he could use it with a router bushing some years ago and posted pictures here. I thought it made the Jasper jig even easier to use, just in case anyone is interested. A search on this site should find it easily.
> 
> Charley


Yes Charlie, Bob's version was a BIG improvement on mine.


----------



## CharleyL (Feb 28, 2009)

Rick,

The only suggestion that I can make about your router circle jig is to be certain that you have all of the thumb screws good and tight before cutting the circle. 

I was using my CRB7 jig and DeWalt 618 router to cut circles from 3/4 cabinet birch ply and my thumb screws were tight, but apparently not tight enough, and my first circle suddenly began to diminish in diameter as I was cutting it. I saved the day by deciding that this piece would now be the smaller of the two diameters that I needed. The smaller diameter circle needed to be 4" in diameter smaller than the large one, and I had luckily been trying to cut the larger one first. 

After cranking down on the thumb screws at both ends of each guide rod for each circle setting, my circles in both pieces turned out perfect. They became the two layered lid to attach my Dust Deputy to my metal 20 gallon re-purposed grease barrel. 

No matter how good we get at woodworking, there still seems to be a woops every once in a while, and this was one of mine.

Charley


----------



## tomp913 (Mar 7, 2014)

The instructions Pat Warner's router circle jig has pretty much identical instructions for setting the pivot pin to router bit distance - he claims that, with care and experience, the circle diameter can be set within a couple of thousandths. His jig, shown in the attached photo, uses a .185" diameter pin (I believe that this is a section of #13 drill bit) which gives a close but workable fit on a 3/16" drilled hole - you can just make out the pin to the left of the clamp knob. I wish now that I'd thought to ask Pat about making the center hole in the plate for a snug fit on a 3/4" guide bushing - I don't know what the actual hole size is but it's quite a bit larger than the biggest standard size - somewhere in the shop I have a circle guide that I made years ago with a 3/4" center hole; to use, I just mount a 3/4" bushing in the router, drop it in the hole and cut the circle. The router doesn't rotate as you cut the circle and so the power cord doesn't wind itself into a know, no matter how many rotations you make to get to the required depth. Pat's jig is a dream to use, very easy to adjust, and I guess I could modify a guide bushing by shrinking a brass/nylon ring on the OD of a guide bushing and using it that way.


----------



## dgwoods (Oct 1, 2018)

Rick,

Nice first design. I've attached Pat Warner's circle jig which I have found to the be the best out of all the circle jigs I've used. Unfortunately Pat passed away and his web site is unavailable, but I used the Internet Archive to get a previous version. 

3/16" or 1/4" dowel pins make for better pivots and are cheap. You're correct about a bit of trial & error on the radius because the router armature and collet have a bit of runout. Also the router bits have a small tolerance.

I copied Pat's design in MDF. I would suggest cast acrylic because it's super handy to see thru the base. My base has seen quite a bit of use and the couple of coats of thinned polyurathane varnish is holding up well. Some paste wax on the bottom helps too. Below are a couple of pics of the build.


----------



## dgwoods (Oct 1, 2018)

tomp913 said:


> The instructions Pat Warner's router circle jig has pretty much identical instructions for setting the pivot pin to router bit distance - he claims that, with care and experience, the circle diameter can be set within a couple of thousandths. His jig, shown in the attached photo, uses a .185" diameter pin (I believe that this is a section of #13 drill bit) which gives a close but workable fit on a 3/16" drilled hole - you can just make out the pin to the left of the clamp knob. I wish now that I'd thought to ask Pat about making the center hole in the plate for a snug fit on a 3/4" guide bushing - I don't know what the actual hole size is but it's quite a bit larger than the biggest standard size - somewhere in the shop I have a circle guide that I made years ago with a 3/4" center hole; to use, I just mount a 3/4" bushing in the router, drop it in the hole and cut the circle. The router doesn't rotate as you cut the circle and so the power cord doesn't wind itself into a know, no matter how many rotations you make to get to the required depth. Pat's jig is a dream to use, very easy to adjust, and I guess I could modify a guide bushing by shrinking a brass/nylon ring on the OD of a guide bushing and using it that way.


Lucky you to have an original. I don't quite understand the 3/4" bushing vs using a 3/4" bit as the OD's are different and how you are doing the setup. That said the Porter Cable guide bushing specs are:

Thru hole: 1 3/16"
Flange: 1 3/8"

The 1 3/8" counterbore is a bit expensive if you work w/acrylic or jig plate.

And yes, you can set the radius to a couple of thou on first try.


----------



## Old_Tom (Jun 28, 2019)

Hi Rick. I made mine out of MDF and it works well. It provides a huge range of circle diameters. Looking at what you did I went back to my trim router accessories and worked out I can produce up to a 13 inch diameter circle with the bits provided with it:shout: Oh well practice I suppose.
Great job mate.


----------



## tomp913 (Mar 7, 2014)

dgwoods said:


> Lucky you to have an original. I don't quite understand the 3/4" bushing vs using a 3/4" bit as the OD's are different and how you are doing the setup. That said the Porter Cable guide bushing specs are:
> 
> Thru hole: 1 3/16"
> Flange: 1 3/8"
> ...


Sorry, didn't make myself clear. When using a guide bushing on the router mated to the corresponding hole in the circle guide, the router is NOT bolted to the circle guide. What this means is that the router doesn't rotate with the jig as you sweep the circumference of the circle being cut ie the router stays in the same position relative to the operator so the guide bushing is rotating inside the hole in the circle guide. This means that the power cord and vacuum hose, supported from above to stay out of the way, stay in the same relative position and don't end up twisted in a know, no matter how many times you need to go around the part to cut through.

Cutting a circle in plywood is a snap, cutting a circle in wood is somewhat of a problem as, depending on the direction of rotation, some segments are being cut against the grain - the solution then is to cut the circle in 4 segments so that you're always cutting with the grain and don't wind up with chip-out.


----------



## pperry42003 (May 4, 2013)

What was the advantage of machining(?) the brass hex "head" verses just cutting the threads longer and having a regular nut on both sides? Actually I bet I know after asking, it was probably because the nut that should be fixed might move while loosening the other nut, and that would cause slight variances in the distance the pin protruded.


----------



## RickKr (Dec 30, 2018)

pperry42003 said:


> What was the advantage of machining(?) the brass hex "head" verses just cutting the threads longer and having a regular nut on both sides? Actually I bet I know after asking, it was probably because the nut that should be fixed might move while loosening the other nut, and that would cause slight variances in the distance the pin protruded.


A couple reasons. First, it is like why dogs lick their... Because they can... 

Kidding aside, I had the brass hex stock and I wanted the pin to be as secure as possible. With nuts on both side the pin can actually be angled. Turning the shoulder on the brass hex stock ensures to a greater degree that the pin will remain perpendicular. Also, I have not looked at it in a while, but I suspect the stock screw can be undersized. My brass pin is a slip-with-no-slop fit. Overkill, but that is how I like doing things. 

The way I've made the brass one, there can be no variation in how far the pin protrudes. 

Rick


----------



## The Hobbyist (Apr 25, 2015)

I got to thinking about this, and decided that I could use my CNC router to make a jig. I stopped at 13" diameter, but basically it could be made to handle any size by calculating more location holes.


----------



## RickKr (Dec 30, 2018)

dgwoods said:


> Rick,
> 
> Nice first design. I've attached Pat Warner's circle jig which I have found to the be the best out of all the circle jigs I've used. ...snip...
> 
> I copied Pat's design in MDF. I would suggest cast acrylic because it's super handy to see thru the base. My base has seen quite a bit of use and the couple of coats of thinned polyurathane varnish is holding up well. Some paste wax on the bottom helps too. Below are a couple of pics of the build.


DG,

Thanks. I am just getting back to this project after a rather extended hiatus. This fall was extremely busy for some reason and THEN the holidays came. Whew. 

In sitting down with my design and the template that I need to route the circles for, for the ships ladder, I came to realize my jig, as is, cannot cut a small enough circle. The pin has to inside the circle inscribed by the router base. I like the Pat Warner design and think I will make one like it. I will probably do it in MDF, as that is what I have. But, I am going to the "city" tomorrow, so maybe I can find some suitable acrylic. I kind of doubt it. Baker City, OR is 10k population in cattle country in NE Oregon. Although there are hardware stores, there really aren't any beyond the stock TV or DIB and I don't recall ever seeing acrylic thick enough. 1/4" yes, but nothing thicker. Gotta check, tho. 

Funny. I do not mean to take any credit for an original thought, and maybe I was just recalling having seen the photos you posted, but before coming back on here, I thought of something remarkably similar, with an adjustable bar extending under the base. At first, I thought of just making a base and drilling a hole at the hopefully right location and make it a one-off. But then, I thought I should make it adjustable. 

I've printed Pat's design and save the photos you posted. I will plan this out (my code for CAD it out) tonight and see what I can find for base stock tomorrow. 

Thanks,

Rick


----------



## dgwoods (Oct 1, 2018)

RickKr said:


> But, I am going to the "city" tomorrow, so maybe I can find some suitable acrylic. I kind of doubt it. Baker City, OR is 10k population in cattle country in NE Oregon. Although there are hardware stores, there really aren't any beyond the stock TV or DIB and I don't recall ever seeing acrylic thick enough. 1/4" yes, but nothing thicker. Gotta check, tho.
> 
> I've printed Pat's design and save the photos you posted. I will plan this out (my code for CAD it out) tonight and see what I can find for base stock tomorrow.


Try freckleface.com for cast acrylic. I have the same problem trying to source raw materials locally.

There are some subtle aspects to making this base so doing it in MDF the first time will be good practice. If your 1st one is good, you can use the MDF as a template for making more of them.

Even if you are doing this w/a CNC router, I would drill a 1/4" hole for the spindle location. Then mount a 1/4" drill rod in the 1/4" router collet. It will let you determine the handle orientation for a particular router. Secondly, surprise, you'll find some tolerances in base plate hole patterns. At least w/this method, you know the base will mount easily on the router. While the PC 690 hole pattern is a near universal standard, the orientation of the handles to the hole pattern is not. It's not until you use Pat's edge guide that you realize how important this is.


----------



## RickKr (Dec 30, 2018)

Thanks, DG. Freckleface is a great site. 

In 1972, I used 3ft long sections of 12" dia. plexiglass tubes as experimental chambers for rapid water exchange tolerance tests of fish exposed to heat and cold shock experiments at a nuclear power plant on the Hudson River (Indian Point). I brought one with me when I left in 1973. I carted that thing around for years, hoping to make a vertical, fish tank. Never did. It became a rolled map storage container and eventually degraded to the point it could not be used as a fish tank. I disposed of it, grudgingly, when I move to my current location in 2016. That kind of acrylic tube is ridiculous expensive now. 

I was sorely disappointed in my search today. Not even 1/4" could I find in Baker City? I'm going to make something out of MDF to get me through this project and come back to making a decent circle jig another time. I do not want to be distracted from getting this ladder done this week. I put it off from Sept., not that it will get much use until Spring, but it is just one of those "things" hanging over me if I don't. 

Nice advice on orienting the handles. I fiddled with that a bit, trying to figure out not only which way the handles should go, but also the plunge release lever, actuated by my left thumb. I found it much more comfortable to have it on the outside of the rotation and on the inside. But, I realize that changes as the router rotates, but for starting the cut with a plunge, it works best on the outside. 

Rick


----------



## RickKr (Dec 30, 2018)

Made the base plate for a Pat Warner style circle jig today and used it to cut the radii for a router template, for making the hand hold cutout in the ships ladder stringers. I printed and pasted a full size pattern for the base plate on to a piece of 1/2" MDF and band sawed the outside and sanded to the lines on a disc sander. Then, drilled a hole for inserting a scroll saw blade and cut out the center hole, then sanded it to the line on a spindle sander. Milled the slots on my vertical mill with DRO, but I don't have the right metal stock for the pivot arm, so did not make that much of the jig today. Instead, for the immediate need, I drilled a 1/4" pivot hole at the right distance from the center of the jig, which can be seen just inboard from the 1/4" wide clamping slot. 

















Here is a test run in a scrap piece of MDF. 









Rats, I was going for 7.040". Missed it by a smidge :wink:









Cutting the radii on the production template. I need to work on dust collection. Dust went everywhere and these were just 1/2" deep cuts. The shopvac hose didn't do a thing, and I even had the shopvac turned on. Chips will come off of the stringer lumber rather than dust as fine as what came off of the MDF, but I still need dust collection very close to the cutter. A dust hood came with the edge guide, but I haven't figured a way to mount it on the router bases yet. 









Straight edges were milled out on my vertical mill. I used a laser center finder to set the stock up, splitting the beam over the edge of the radius and then shifting over about 0.150" to rough it out. Then a final cleanup pass at 0.125". 









The completed cutout. I had backed the template up from the mill table with 1/4" Baltic birch plywood scrap, which was screwed to the center section for the second cutout, so the middle part would not be loose as the cut was complete. 









There are some small rises at the transitions from the straight edge to the radii. I'll blend those tomorrow with a spindle sander and then it should be ready to try out. 

This template is for creating cutouts for the handholds. The cutouts will be started by boring holes on each end with a large diameter forstner bit and the sides with be cut with guided, circular saw plunge cuts. These are going into 12 ft long stringers of 2x12 fir boards. The stringers will be on sawhorses. I have another template for guiding the circular saw cuts and will get close to the final dimensions. Final size will be done with the router/template and a 1/2" dia. straight router bit. 

If there is a better way to make the straight cuts in these boards, I'm eager to hear about it. I'm not thrilled about making the plunge cuts in the 2X boards, but that is probably because I haven't done it much. I'll be testing it all out on scrap before going to the stringers. 

The hand holds will be finished with a 1/2" radius roundover bit. 

Rick


----------



## PhilBa (Sep 25, 2014)

A lot of work but it looks like you got a good result.

This sort of thing is one of the reasons I bought a CNC machine. I would labor over making a template but could never quite get it perfect. There were always a few imperfections. They were "good enough" and no one ever even noticed but I knew I could do better. Now, with my little CBeam CNC machine, I can crank out perfect templates every time. And I can make much more complex templates too. It's definitely a game changer for me.


----------



## RickKr (Dec 30, 2018)

PhilBa said:


> A lot of work but it looks like you got a good result.
> 
> This sort of thing is one of the reasons I bought a CNC machine. I would labor over making a template but could never quite get it perfect. There were always a few imperfections. They were "good enough" and no one ever even noticed but I knew I could do better. Now, with my little CBeam CNC machine, I can crank out perfect templates every time. And I can make much more complex templates too. It's definitely a game changer for me.


I was thinking about CNC as I did this. Thought the use of the mill with DRO was a touch toward that. I like figuring out stuff, like making the templates, but when they take longer than the project they are being made for, it looses its shine. 

Rick


----------



## PhilBa (Sep 25, 2014)

RickKr said:


> I was thinking about CNC as I did this. Thought the use of the mill with DRO was a touch toward that. I like figuring out stuff, like making the templates, but when they take longer than the project they are being made for, it looses its shine.
> 
> Rick


DROs are great and for certain things loads faster than designing in CAD, making GCode in CAM (and getting it right) and then actually cutting. And both CAD and CAM have learning curves, sometimes steep. Hard to make arcs-n-circles with a DRO'd mill, though. 

I have a Sherline mill and a lathe that I sometimes use to cut steel and such. Wish I had DROs on them. Either that or CNC upgrades. Using calipers gets old fast.


----------



## RickKr (Dec 30, 2018)

I have avoided getting in to CNC with my metalworking machines. I have DROs on my lathe (two axes) and on my knee mill (three axes) and love them. I no longer even look at the dials, except the compound on the lathe. 

For some project involving radii, I've used a rotary table on my mills, first a minimill, then a milldrill and now a small knee mill. I'd love to have a full sized Bridgeport type mill and now, in my new location, I have the room, just haven't put the effort into finding one. 

Despite not wanting to get into CNC with metalworking, I am very tempted to do so for router work. 

Rick


----------



## RickKr (Dec 30, 2018)

*Template Designed for Fixed Base*

Completed a dust hood for the plunge base (Bosch 1617EVS) by making a plywood base. The best existing holes for mounting it were 1/4" dia. but were without threads. So, I put in some M6 threaded inserts. The holes were already the correct size for threading oversized (part of the kit) and screwing in the inserts. Very clean. This is the first time I've used threaded inserts in metal (which is what they were intended for in the first place).

It assembled just fine, but I failed to account for clearance of the locking lever. I'd have to move it outward about 1/4", which leaves much larger gaps on both sides, which does not thrill me. As it is, there is not a lot of depth (~9/16") for a 1/4" bit, which is recommended for cutting circles. This would work for 1/2" stock, which may work for most applications. 

But... Once this was done and I realized its limitation and thinking I needed more depth, I started thinking about using the fixed base instead. Then I realized my template, which I just completed using the plunge base/circle jig setup, I designed it for use of the fixed base, not the plunge base. The latter is larger diameter and would not work. So, now I need to remake a mount for the fixed base. 

There are three threaded holes on the open side of the fixed base, two of which are used for mounting the base plate (M4). I'll have to add at least one threaded hole. But, I think I'll like using the fixed base better. The provided acrylic guard fits in the other side and the dust hood that I fitted to the plunge base will fit closer with less gap that is easier to fill with the fixed base. In looking at how the hood fits, I think it can be modified, by sanding out a radius to match the fixed base and get the hood in closer to reduce the gaps. 

I sure hope this one works. I'd really like to get on with the actual ladder project. 

Rick


----------



## RickKr (Dec 30, 2018)

RickKr said:


> ...snip...
> 
> I sure hope this one works. I'd really like to get on with the actual ladder project.
> 
> Rick


I decided I'm spending way too much time and energy futzing with this dust hood. I broke down and ordered Bosch three hood kit for the 1617EVSPK, for both the fixed and plunge bases. It won't get here for a week, but there is lots of prep work on the ladder stringers before I'll need it, and that is if I can even get that much time in before it arrives. 

I'm moving on to figuring out the circular saw plunge cuts and drilling the holes. I have the template for the plunge cuts made, just need to figure out if it will work as I want.

Rick


----------



## RickKr (Dec 30, 2018)

Template for routing the handhold outline works just as planned. Width and length are spot on, so I'm quite pleased. I did forget to smooth out the transition from the radius to straight sections, so I'll need to do that before using it on the stringers. 

















My temporary dust hood: Packaging tape. Worked. Dust still got out, but nothing like without any hood. 









Rick


----------



## tulowd (Jan 24, 2019)

I really like modifying my tools as needed. The circle templates are a real common thing; I chose to buy a pre made one when on sale and modified it to suit my needs for now. There is also a very cool alum template available from/for the car audio world, since most speakers have unique basket sizes and many of the installations require 3 or more cutouts to flush mount the speakers with associated trim and beauty panels. Usually there is also a 1/8" clearance required for fabric/leather/vinyl upholstery coverings so the need for many precise, repeatable circle cuts is part of a high end shop environment. Adjustable means measuring and having to ensure perfect alignment, which is not easy.

Below is an interesting alternative, which our resident CNC guys could likely duplicate easily. There was an aluminum version (larger IIRC) but I can't find it.


https://www.amazon.com/Jasper-200J-...03-20&linkId=035df10f982e87a2f23a3dbe3083d009

There is also a pretty slick high end 3 router table setup: https://www.mobilesolutions-usa.com/knowledge-lift


----------



## RickKr (Dec 30, 2018)

Took a brief detour with a different thread about plunge cutting with a circular saw for making the initial cutouts for the handholds on this ladder. https://www.routerforums.com/tools-woodworking/140811-cicular-saw-plunge-cuts.html

Trial sawing run worked out, so I moved on to working out the router jig for making the handholds full sized. The jig was used to cut a finished edge about 1/2" deep. Then a bearing guided 3/4" straight bit was used to finish the rest of the 2X width. Followed by 1/2" roundover inside the handhold and along the outer edge. 

Worked out very well, I think. Thanks for all the help. 

Rick.


----------



## jw2170 (Jan 24, 2008)

You do realise you have also made the perfect template for bowls and dishes..


----------



## dgwoods (Oct 1, 2018)

RickKr said:


> Made the base plate for a Pat Warner style circle jig today and used it to cut the radii for a router template, for making the hand hold cutout in the ships ladder stringers. I printed and pasted a full size pattern for the base plate on to a piece of 1/2" MDF and band sawed the outside and sanded to the lines on a disc sander. Then, drilled a hole for inserting a scroll saw blade and cut out the center hole, then sanded it to the line on a spindle sander. Milled the slots on my vertical mill with DRO, but I don't have the right metal stock for the pivot arm, so did not make that much of the jig today. Instead, for the immediate need, I drilled a 1/4" pivot hole at the right distance from the center of the jig, which can be seen just inboard from the 1/4" wide clamping slot.
> ...snip...
> Rick


Rick - It looks like you are making good progress. Appreciate all the photos you included. My comments span a couple of your posts. 

Looks like the router base sits inside the template to make the ladder hand hold. If my interpretation is correct, then read on. The OD of the router base is typically not centered around the bit and manufacturing variations may make it difficult to achieve that relationship. Instead, use a 1" guide bushing and center it around the bit. I think Bosch does not follow the PC standard, but has their own. Just be sure the bushing is firmly secured to the base plate. The advantage of a 1" guide bushing is you can center it by using a 1/2" precision ground rod placed tangent to the center line. The 1" collar also lets you change bit diameters while keeping the jig in place so you add a (small) rabbit w/only a bit change. Or have an other router w/a 1" guide bushing.

Also by having the router base fully supported by the template, you can route on narrow stock or closer to the edge. It also keeps the router perpendicular to the stock in case the stock is not entirely flat. I have a couple of Pat's extended plunge bases with the guide bushing center hole. They are 6 - 7" in diameter depending on the model router. The trim router is smaller. It looks like you have the machinery to recreate them.

In one of your pics, I think you used a threaded insert for attaching the router base to the MDF base. There is a lot of space to collect chips. Pat countersinks a flat head screw or counterbores for the centerable bases and there is much less space for chips to collect. I had a lot of discussions w/Pat about extra holes & spaces in the base and he was very firm - no extra gaps for chips to collect. After a couple of years of my own jig designs, I found that crud will find every opportunity to collect and can throw off the accuracy of the path by a few thousands of an inch. You eye is very good at detecting these variations so you don't see the straight line you wanted.

Also seal the MDF bases with 2 coats of thinned polyurethane and then wax the bottoms. It will make the bases much more durable and glide on the templates.

Home center 1/4" x 1" T6061 extruded bar stock works well for the pivot arms. Check to make sure the bar is not bent from rough or careless handling. Once home, hone one edge to be flat to 0.001" along it's length. Then remove the mill marks on the top & bottom. Measure the width of the bar in multiple places and record them. You'll find that the bar is likely a couple of thou under 1". Now mill the slot in the circle base to be +0.003" wider than the actual bar dimensions for a snug fit. When you get to drilling holes in the bar, center the bit to the actual width. This will allow you to flip over the bar which is sometimes handy.

As far as removing the waste from the hand hold, jig saw to 1/16" of the final edge and then route the final edge. It's a huge mount less wear on the bit and dust for you to breathe or clean up.


----------



## RickKr (Dec 30, 2018)

dgwoods said:


> Rick - It looks like you are making good progress. Appreciate all the photos you included. My comments span a couple of your posts.


You've certainly given me a lot to think about. Thanks. 



dgwoods said:


> Looks like the router base sits inside the template to make the ladder hand hold. If my interpretation is correct, then read on. The OD of the router base is typically not centered around the bit and manufacturing variations may make it difficult to achieve that relationship. Instead, use a 1" guide bushing and center it around the bit. I think Bosch does not follow the PC standard, but has their own. Just be sure the bushing is firmly secured to the base plate. The advantage of a 1" guide bushing is you can center it by using a 1/2" precision ground rod placed tangent to the center line. The 1" collar also lets you change bit diameters while keeping the jig in place so you add a (small) rabbit w/only a bit change. Or have an other router w/a 1" guide bushing.


I considered the guide bushing approach. I have the adapter for using the bushing, but no bushings yet. I have not paid any attention to centering the base plate on the router base. I'll look at that and see if it can be centered. Even if it can't be well centered, I think for this project, it won't really matter. The finished outline of the handholds will be created by a "shallow" router pass using the jig. That outine will be followed by the longer, bearing guided bit. The actual size/location will not matter if offcenter slightly due to the base plate not being fully centered. 

I do want some of the guide bushings. The Bosch mounting system seems a bit funky. What little I've fooled with it, it seems to not hold the inserts securely. But I only have the adapter to go from the Bosch mount to the traditional bushings, so I can't tell just how well it really works. 



dgwoods said:


> Also by having the router base fully supported by the template, you can route on narrow stock or closer to the edge. It also keeps the router perpendicular to the stock in case the stock is not entirely flat. I have a couple of Pat's extended plunge bases with the guide bushing center hole. They are 6 - 7" in diameter depending on the model router. The trim router is smaller. It looks like you have the machinery to recreate them.


I have run into the problem of the base not being fully supported when rounding over the outer edge, so I need to deal with this somehow. It looks like it will work to attach the circle jig that has the extended wing as it spans the handhold gap to provide that support. 



dgwoods said:


> In one of your pics, I think you used a threaded insert for attaching the router base to the MDF base. There is a lot of space to collect chips. Pat countersinks a flat head screw or counterbores for the centerable bases and there is much less space for chips to collect. I had a lot of discussions w/Pat about extra holes & spaces in the base and he was very firm - no extra gaps for chips to collect. After a couple of years of my own jig designs, I found that crud will find every opportunity to collect and can throw off the accuracy of the path by a few thousands of an inch. You eye is very good at detecting these variations so you don't see the straight line you wanted.


Yup, finding this out. With my very crude taped up dust hood, I noticed chips flying out of the holes where the edge guide bars go. I haven't noticed chips collecting in recesses, but then I haven't done a lot of this yet. I'm waiting for the Bosch dust hoods to arrive before tackling the rest of the routing. I must drill and saw the center waste out first. Today, I should clean my shop of all the chips/dust from yesterday's activities. Yesterday, I slipped on ice in my driveway and sat full force on by bottom. My back is telling me about it today, so I may not get much done today. Tomorrow I go in for a periodic colonoscopy, so I won't be working again until at least Thurs., by which time the hoods should have arrived. 



dgwoods said:


> Also seal the MDF bases with 2 coats of thinned polyurethane and then wax the bottoms. It will make the bases much more durable and glide on the templates.


Good suggestion. I had not really considered this, as I was thinking the MDF one is just temporary, until I can get some 1/2" acrylic. But, as many things go, temporary solutions often become more permanent. 



dgwoods said:


> Home center 1/4" x 1" T6061 extruded bar stock works well for the pivot arms. Check to make sure the bar is not bent from rough or careless handling. Once home, hone one edge to be flat to 0.001" along it's length. Then remove the mill marks on the top & bottom. Measure the width of the bar in multiple places and record them. You'll find that the bar is likely a couple of thou under 1". Now mill the slot in the circle base to be +0.003" wider than the actual bar dimensions for a snug fit. When you get to drilling holes in the bar, center the bit to the actual width. This will allow you to flip over the bar which is sometimes handy.


I milled the slot to fit a precisely 1" bar with 0.003-0.004" clearance. I'll find some nice bar to fit, possibly from a big box store, or by ordering online. The closest big box store is 3hrs away in Boise, ID, but I'm likely to make the 6hr trip to Portland, OR sooner. Plenty of options well beyond big box stores in Portland where I can examine the stock before buying. I've got the drilling/tapping down. I use a laser edge finder to center work in my mill and then center it, setting the DRO to zero and then use the DRO to space holes along the length. I have precision reamers for making the pin holes to precisely fit the guide pins. And I use the mill for power "rigid" tapping, using a very slow infeed speed and the VFD to instantly reverse to back the tap out once the depth is achieved. 



dgwoods said:


> As far as removing the waste from the hand hold, jig saw to 1/16" of the final edge and then route the final edge. It's a huge mount less wear on the bit and dust for you to breathe or clean up.


Jigsaw has been suggested/recommended by several. I will be using my circlular saw, plunge cutting, rather than a jigsaw (which I don't have). The end radii will be created using a 1 3/8" forstner bit. The saw cuts don't reach the end holes so a little bit of hand sawing will remove the final webs left by the circular saw. 

Thanks for your thoug


----------



## RickKr (Dec 30, 2018)

I got a table-top drill press set up today and drilled all of the end holes (28) for the handholds today. 

I had started out trying to do it using a cordless drill in an ancient "Portalign" tool. It was very difficult to control hole placement, which I really needed to do well. I had been working on putting back in operation a very old Delta bench top drill press (1943), with an even older (but working) motor (1941). While trying to remove the pulley from the old, burned out motor, I ruined it. I got a new-old stock Delta pulley over the holidays and today had the motivation to get the replacement motor & pulley installed and set up, as I really needed it for this job. 

After getting the motor and pulley installed and laying out all the hole locations earlier in the day, it took about an hour to get roller stands set and the setup for guiding, positioning and clamping the ladder stringers over the drill press table. It then took about an hour to drill all 28 holes. The roller stands on both sides of the drill press really made it easy to move the stringers to the next hole position. Then, centering the desired location under the 1 3/8" Forstner bit point and clamping that down with the quill lock followed by clamping the stringer to the drill press table. Release the quill lock, turn it on and begin drilling. This was SOOO much easier and faster than using a cordless drill. I was actually concerned about burning up the cordless drill motor, with how many and how heavy the drilling operation was. It was a breeze with the drill press. And, I was able to sit for the entire operation. What a pile of chips. I'm going to see if my daughter wants if as bedding for her chickens. 

Tomorrow, after shoveling more snow at my daughter's, I'll tackle the circular saw cutting out of the center waste. The router jigs are all made, tested and ready for use. This whole process of making the handholds is finally coming together. 

Rick


----------



## RickKr (Dec 30, 2018)

Made some progress today, after shoveling snow at my daughters. I made all of the handholds in of the stringers. First, I had to make all the saw cuts. That went very smoothly, but I really concentrated on placement, control and smooth, methodical movements. Then, I just had to try out the routing jig to make sure things lined up. They did well enough to proceed, but by no means dead on. Center waste was cut free using a hand crosscut saw that I just had resharpened. Cuts real nice. 

Routed handhold profiles in a two-stepped process, first using the jig cut a rabbet wide enough for the bearing guided straight bit as the second step. I had to do it this way because I don't have a straight bit long enough to span the 2X width. One had some serious tear out, which I will likely have to deal with later. Then rounding over on both sides. 

I opted to not roundover the front edge just yet. That would require removing the taped-up jury-rigged dust hood from the fixed base. So I want to wait for the Bosch router dust hoods that are due to arrive Monday. Dust and chips went everywhere. I don't know how much these Bosch dust hoods will reduce that by, but it has to be better what I'm using now. I may even wait for the dust hoods to tackle the other stringer. 

Rick


----------



## RickKr (Dec 30, 2018)

*Handholds are Done*

Tackled the other stringer today, again after shoveling snow at my daughter's. Circular saw plunge cuts, handsaw cutting center free, routing the handhold outline in a rabbet, bearing guided finishing the rest of the outline, roundover edges of handholds and the outer edges of the stringers. Funny thing, I did not wait for the dust hoods coming on Monday. 

Now for the the rungs and it will be ready to install. 

Rick


----------



## The Hobbyist (Apr 25, 2015)

I am wondering ... for a dust collector for hand routing, could you mount a router into a modified 2 gallon paint bucket?

Imagine a router with the base mounted to the lid of a paint bucket that rides on the lid. Popping the bucket off of the top would allow you to change out bits with wrenches. A front window could be made by pop riveting a sheet of Lexan over a square hole. Lights could be put inside around middle. The handles could be mounted to the bucket itself, and a remote switch is easy enough to install. The bottom (now the top) could be fitted with a standard shop vac outlet for the hose to suck chips out through the top of the housing. The LARGE lid base of the bucket would slide over material and keep the router flat and level. The recess in the lid could be filled with a 1/2" sheet of Teflon or whatever. Small holes through the sides covered by screen material would allow air to be sucked into the bucket to carry out the chips. For plunge routers, two buckets nested, the top half with the hose telescoping over the bottom half with the lid?

Hmmm ... That might be worth a Saturday afternoon experiment!

Joe


----------



## RickKr (Dec 30, 2018)

*Routing Rabbets for Ladder Rungs*

Although the design for this ships ladder that I was generally following used rabbets to locate the treads/rungs, I initially was not going to do it this way. I was going to use a 2x4 block underneath and screw the rungs in from two directions. Then I realized I could probably use the jig that I made for sawing the center waste sections of the handholds for routing such rabbets. And I definitely liked the thought of cleaner lines. 

So, I started checking it out. I had to widen the jig for the rabbets because the saw jig was designed so the saw cuts would be about 1/8" inside of the final dimension, 1 1/2". That was easy as it it amounted to simply moving one side only. Doing that and applying a fence at the 20º angle the treads needed to be, a trial run showed that it worked very nicely. Nice to be able to reuse that jig. 

I had dismantled the taped up dust hood, so I made this trial without any dust hood and of course dust went everywhere. The hoods I ordered are supposed to arrive tomorrow but tracking it via UPS they may not arrive until Thurs. I don't want to wait, but I do not want to proceed without the hoods and I don't have a clue how effective they will actually be. Decisions. Patience. Ugh!

Rick


----------



## RickKr (Dec 30, 2018)

The Hobbyist said:


> I am wondering ... for a dust collector for hand routing, could you mount a router into a modified 2 gallon paint bucket?...snip...
> 
> Joe


I couldn't quite follow your description. Sounds really complicated. Let us know how it goes if you give it a try. Photos would really help. 

I did try clamping a cardboard box to the underside of the handhold cutouts, with two things in mind. First, I was hoping it would catch much of the dust that was falling down through the slots. Second, I was hoping it would allow the dust hood to be more effective, by keeping dust up close so it could be sucked away. Didn't work. I'm not if my shopvac is not working up to snuff. So, I gave up on it and just swept it all up afterward. 

Rick


----------



## dgwoods (Oct 1, 2018)

Rick,

Double ouch a couple of replies ago. The base below has an opening that's too large.










The first point is removing all that material in the middle leaves less support for the router, esp. for narrower stock. And the MDF itself could use some more support. Secondly, the max dia of a bit for handheld router use is 1.75". This is Pat's number and I agree w/him. Besides preventing the use of panel raising bits in an under powered router, it precludes one from using a 3 wing slot cutter, the next stupidest thing :frown:. Slotting in the middle of stock is a trapped cut and if the stock is not flat or the router wiggles, all hell will break loose.

I don't have anything against Bosch routers, but I think a different router would result in less fighting the tool. Craigs List usually has a good selection of used ones and you do need more than one router. I'm 80% serious and 20% joking. For hand held use, Pat's choice is the Dewalt 621, which features a built-in dust collection port. It's not perfect, but he designed all his jigs and bases to work with it. I've had my hands on one in a store and think that it has lots to offer, but some annoyances too.

My Milwaukee 5616 (?) and PC 690 (1992 vintage) plunge bases were both miserable until I reduced the spring tension. Simple process to reduce the OD by 5% using a bench grinder. Adjusted the preload by cutting off 1/2 a coil.

You can read about my drill press adventures here: owwm.org/viewtopic.php?f=1&t=210398


----------



## RickKr (Dec 30, 2018)

dgwoods said:


> Rick,
> 
> Double ouch a couple of replies ago. The base below has an opening that's too large
> 
> ...


Thank you DG. I had no idea on either point. I made the opening that size to match the router base. I sure had no intention of using bits anywhere near as large as the opening, but it is good to get this cautionary information. 

Easy to make another with a smaller opening. I wonder if that would also make for better chip extraction by a dust hood. 

BTW, the dust hoods did not arrive on Monday. UPS showed them arriving Thurs. I've been making good use of the time, working on other aspects of the ladder, playing with my granddaugther after school and shoveling snow at my daughter's during school. 

Rick


----------



## mkoukkgou333 (Feb 21, 2020)

Good thinking


----------

