# What's the best jig for this cut?



## DrumSteve (Jan 30, 2006)

Hey everyone,

I'm a new guy here with a dilemma of sorts. I'm trying to make a cut the shape of a U bolt 2 3/4" wide, and ranging from 7 to 10" long. I'd like to use a 3/16" bit, but the padouk I'm routing is 3/4" thick, so the smallest I've found is 15/64. 

Anyway, I made a quick jig that was approx. 3" larger than my workpiece (the distance from bit to edge of my router base) and ran it around the inside of the jig, but even after lots of practice on scrap wood it still wasn't what I'm wanting.

I have a small router table (and will get bigger and better if need be) so I'm wondering about using that. I know it's been done before and I need to do it several times, so I want something solid - and am willing to take time to make the best thing.

Any ideas from anyone to help in this situation?

Many thanks in advance.

Steve


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## reible (Sep 10, 2004)

DrumSteve said:


> Hey everyone,
> 
> I'm a new guy here with a dilemma of sorts. I'm trying to make a cut the shape of a U bolt 2 3/4" wide, and ranging from 7 to 10" long. I'd like to use a 3/16" bit, but the padouk I'm routing is 3/4" thick, so the smallest I've found is 15/64.
> 
> ...


 Hi Steve,

Glad you joined the fourm... so let's talk routing...

I'm not sure if I understand just what you are doing...... are you making a groove that is "U" shaped in a piece of wood or are you trying to make a piece that looks like a "U"?

What equipment do you have to do this, router wise and shop wise?

One of the first points I noticed was that you were using the sub-base of the router as an edge. This can be done but unless you have made sure the sub base is centered to the bit and round (or other shape??) this might not work well. Are you aware of what template guides are?

Now I know I have not solved your problems but if we get a bit more information someone here can, most likey anyway. Mind if I ask just what this is for? Some times that helps too.

Ed


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## DrumSteve (Jan 30, 2006)

Ed,

Here's some more info that might help. I am making log drums - boxes that have tops made of padouk. The tops need two "tongues" cut in them - shaped like a "U" and cut completely through, at various lengths (depending on the drum), with the curved parts facing each other - wish I had a pcture to post.

Anyway, in my shop I have the typical stuff - table saw, drill press, router table, etc. For this project I'm mainly using a Porter Cable dovetail jig and DeWalt DW618 with both bases. I've adjusted the sub base to be centered but I do have template guides that came with my dovetail jig.

To be honest, what I'd love would be to have a jig made out of plastic jig stock that I could just set my router guide down into, but I don't know that I coud make one myself.

Thanks again for any help you might be able to provide.

Steve


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## reible (Sep 10, 2004)

Hi Steve,

Would it look something like this:
http://www.manigua.org/musical_instruments/log_drums_forsale.html

Ed


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## DrumSteve (Jan 30, 2006)

Hey Ed,

Yes - same idea, different design.

My design only has two notes on it, rather than the 6 in the pic. Imagine holding two U bolts side by side so that the curved edges are facing each other, an inch apart. 

From the looks of the pic, they just drilled pilot holes and used a jig saw to cut the work. I've done that (that's what I do now) but I'm looking for something more consistent and less time consuming.

Thanks again for your time - and anything else you can think of to help me out would be great.

Steve


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## reible (Sep 10, 2004)

Hi Steve,

Just had a look in my wood book to see what issues your wood might show up, but the workability is good (but does dull cutters slightly)...... now you mentioned the need for 3/4" thick material to right? You will need to get a up spiral bit of the correct dia. and long enough to cut through the material... I checked a couple of catalogs here at my desk and did not find anything longer then 3/4" cutter length... Anyway you will need to make 3 or 4 passes or maybe more to make the full depth cut. I sugest you get this type bit if you don't already have one, it will help clear the chip load.

Since you have a couple of guide bushings would any of them happen to be 1/2"? A large size would be good but I think anything smaller could become an issue getting rid of the chips.

Anyway what you did was along the right lines. A pattern that would be longer then the longest cut you need to make, the off-set to match the bit/bushing and one that has room to clamp the workpiece and pattern to a sub-top. This will allow you to use the guide bushing to make the cut a better solution the routers sub-base. 

The direction that you move the router has to pull the bushing against the pattern, if you do this the wrong way you will not get a nice looking cut. All in all you are close to having it working with what you did... just a little fine tuning is needed.

You can also decide on a few options like a stop to adjust how long the legs are and maybe a jig to cut both "U"'s with one set-up.... and if all of these parts are the same then you can even let the jig locate the cuts for you on your top.

I could make up a quick sketch in a day or so to give you some more pointers if that would help... things like the shape and router direction????

Ed


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## DrumSteve (Jan 30, 2006)

Ed,

You're right about the wood - it does dull my bits/blades some due to the density. But it's one of the better woods for the application.

As for the thickness, I could always plane it some to slightly less than 3/4 if that's too thick; but if I need to make several passes, I would think 3/4 is fine. It'll just take more time to get throught it. 

And, I'll definitely check on the up spiral bit. I've been trying so hard to find a straight bit with a small dia. that I've overlooked a spiral bit. As for the bushings, not sure off hand, but I believe I have 1/2" and 5/8". 

What you're desribing is exactly what's been floating in my head for the past couple weeks. I want to be able to adjust the length of the legs and having one jig for both cuts would be ideal. But actually making the jig is new to me. I completely forgot the bushings and went for the sub base idea - not bad, necessarily, but not the best way to go about it. 

I would sure appreciate any sketches of ideas you may have - at this point, you're keeping me from giving up on my ideas  

And thanks a ton for the time!

Steve


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## DrumSteve (Jan 30, 2006)

Oops... just measured my bushings and they're 5/8 and 3/4" No 1/2".


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## reible (Sep 10, 2004)

DrumSteve said:


> Oops... just measured my bushings and they're 5/8 and 3/4" No 1/2".


 Hi,

Sorry I'm running a little behind in my posts...... anyway the guide bushing are fine. I did get started on the drawing but they had to get set aside... I will try to get back to them real soon and post them.

Did you find a bit of the right size? Also are the tops always the same size?

Ed


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## DrumSteve (Jan 30, 2006)

Hey Ed,

I am having a hard time finding a bit, as a matter of fact.  I've found 1/8" spiral cut bits, but the longest I've found is only 1/2". I'm guessing I'd have to make a couple passes on one side, then flip it over, but I was hoping I could avoid it. I thought I'd found one long enough on the internet somewhere, but can't find it locally in any stores.

What do you think?

Steve


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## reible (Sep 10, 2004)

Hi Steve,

hartvilletool RRU1800 3/16" dia. 3/4" cutter lenght $14.99
infinitytools 85-106 3/16" dia. 3/4" cutter lenght $15.90

I have some infinity bits they are nice... don't have any from hartville but I have gotten other thinks I like from them. I had 4 catalogs here by the computer so 2 out of 4 is not bad... feel free to search somemore.

I still hope to finish up some other items and get back to the sketches I promiced...

Ed


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## DrumSteve (Jan 30, 2006)

Ed,

Thanks for the info on the bits. I've been researching them most of the evening and found that Infinity seems to be the best for my needs - I found some others but still not long enough. So I've got one from them on the way. 

Still excited to see what you're able to come up with concerning the jig. I've been working on different ideas, but still not too much luck. I can't seem to get anything solid enough yet. 

Steve


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## reible (Sep 10, 2004)

OK off we go.

First the basic thing you want is shown in attachment 1. If I don't have dimensions correct or shapes don't worry about it... this is for concept only.

The dimensions can be changed to meet your needs and more then one of these "holes" can be added to a template but we will get into that another day.

To make sure you know what we are doing let me start this with the tools/materials needed for a "test". Before we get to far into this I'd like to know how the "small" cutter is going to do and how you feel about what and how the jig works. To start with let's assume that you have the router set-up to do plunge work, have a guide bushing (lets start with 5/8") and the bit you want to use. You will need some plywood/masonite/plastic or what ever to make a template out of. The material needs to be thicker then the depth of the barrel of the guide bushing... If the depth is less then 1/4" then any 1/4 material will work for this.

Now we need to know how much larger the cut out in the template needs to be then the hole you want to rout. Take a look at the second attachment, the "?" needs to be filled in. If you know how to do this then we can keep going if not give it a shot (guess) and let us know. I will let you know if that is the correct dimension. (Knowing how to do this is importain if you decide to change things later.)

Now we can do a layout of the cut-out. Remember that the radius also changes so I would do the real hole layout followed by the layout for the template. (make sure the tempate board is large enough to allow for clamping without having to move clamps when working) When the layout looks good then cut out the area leaving the line. Using a jig saw or simular. Sand to the line getting the template as smooth as you can. Take a look at the third attachment for some additional hints.

When you are done it is time for a test, use some scrap wood as the workpiece for this test. For this time it would be OK to screw the template to the scrap, make sure you have a scrap piece under it as well as you will be routing through. Set the pole stop on the router so the bit just makes it the depth of the workpiece plus a touch. Then plunge cut using a shallow cut and moving in the direction indicated. Do this as many times as it takes to go through.

If the results are what you are looking for then we can move on to the next phase otherwise we might have to adjust somethings and get this part working before we spend more time with the second jig...

Some thought as to what might follow...... 1) being able to have a jig that will do various lengths of cuts with stops. 2) a simple clamping method using wedges to hold the workpiece where you want it. 3) a way to locate the workpiece. 4) being able to do more then one cut without moving the workpiece....

Ed


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## reible (Sep 10, 2004)

hEY WHO CAN SLEEP ANYWAY????

i DID A CONCEPT FOR YOU.

fEAUTURES ARE AS SHOWN AND AS NOTED BEFORE. tHE SLOTS ARE CUT IN THE TEMPLATE AND USE CARRIAGE BOLTS FROM THE UNDERSIDE AND MAYBE 3/8" THICK PIECES WITH HOLES AND A KNOB TO LOCK THEM IN PLACE. tHE STRIPS BELOW WILL NEED TO BE NOTCHED OUT IN THAT AREA TO ALLOW FOR THE BOLT HEAD.

tHE TWO TEMPLATES SHOULD BE MADE AT THE SAME TIME TO INSURE THEY ARE IDENTICAL. THEY ARE ADJUSTABLE FOR SPACING BETWEEN THE "u"'S AND THAT IS JUST LOCATIONS FOR SCREWS ALONG THE TOP RAIL BOARD.

A SECONDARY BOARD CAN BE SEEN AT THE TOP, THIS CAN BE FASTENED TO SHORTER WORKPIECES AND CAN BE USED TO ADJUST THE HORZ. CENTER LINE. tHE BOTTOM PIECE IS THE SAME WAY AND THE WEDGES CAN WORK AGAINST THAT RATHER THEN THE WORKPIECE JUST MAKE SURE THE WORKPIECE CAN NOT MOVE.....

yOU SHOULD VACCUME THE DUST OUT OFTEN TO MAKE SURE THE TEMPLATE RIDES THE PATTERN.

tHERE ARE MANY WAYS ONE COULD DO THIS BUT AT LEAST THIS WILL GIVE YOU ONE OF THEM... FEEL FREE TO USE WHAT YOU WANT AND CHANGE WHAT YOU WANT....... oNE THING THAT CAME TO MIND WAS USING SCREWS TO HOLD THE PATTERN TO THE WORKPIECE.... WITH THE WORKPIECE UPSIDE DOWN (i DON'T THINK THAT YOU CAN SEE THAT RIGHT?)

hINT: YOU WANT THE WORKPIECE TO JUST SLIDE IN HEIGHT WISE SO KEEP THAT IN MIND WHEN FIGURING THE HEIGHT.

eD


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## template tom (Sep 18, 2004)

DrumSteve said:


> Ed,
> 
> Still excited to see what you're able to come up with concerning the jig. I've been working on different ideas, but still not too much luck. I can't seem to get anything solid enough yet.
> 
> Steve


Hi Steve

I was not sure of the size of material you were using Length and Breadth so I have put in 240mm x 200mm.

The way I would tackle the problem is first.. 
How am I going to hold the material secure. 
Answer secure it to a jig 400mm x 300mm x 12mm MDF Cams and Packing pieces.

The jig is placed in the Jig Holder internal dimensions 400 x 300 x 40mm deep. Made from 19mm pine.

The template with the cut out is also 400 x 300 x 12mm MDF.

The template guide I would use is 40mm in diameter. The reason for such a large guide is the chuck will fit through the guide to give me the depth that I want because as you say the cutters are in the shorter range when using small diameters.

Tom


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## DrumSteve (Jan 30, 2006)

Thanks to both of you for the ideas - and Ed, for the late night brainstorming  

I'm curious Ed about your jpegs - the first one has a "channel" for the hole that I'm making, and the third one has the entire area cut out, inplying that the bushing only follows on the outside of the cut. Do you think the template guide would need to have a channel for it to follow, or would it be enough to have it just follow on the outside? It seems to me that a channel would be more stable, but it sounds like something I'd have to have a CNC router for  I don't know if I could be precise enough to cut a channel like that.

I'm still deciphering your last jpeg and will get back to that later.

And Tom, you idea of a large guide is right on - getting the extra plunge depth fron that is what I'm going to need so I don't have to worry about losing my bit.

You guys are the best!

Steve


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## reible (Sep 10, 2004)

DrumSteve said:


> Thanks to both of you for the ideas - and Ed, for the late night brainstorming
> 
> I'm curious Ed about your jpegs - the first one has a "channel" for the hole that I'm making, and the third one has the entire area cut out, inplying that the bushing only follows on the outside of the cut. Do you think the template guide would need to have a channel for it to follow, or would it be enough to have it just follow on the outside? It seems to me that a channel would be more stable, but it sounds like something I'd have to have a CNC router for  I don't know if I could be precise enough to cut a channel like that.
> 
> ...


 Hi Steve,

The first image with "wood grain look" is your workpiece with the cut out. The third image is what the template looks like, and yes you would follow the outside edge of the template.... No don't use a channel as the dust will not clear very well from that type of template and this application. (they are really not hard to build but that is another project)

As for template guide size, everything is a trade off... I picked one that you mentioned you have. One other trade off is as the guide bushing gets larger the larger the template cut out becomes and at some point the router will only have the sub-base sitting on the edge near the contact point, the other side will be over the cut out area so you can get tipping happening....... as you do this more it isn't so bad but for beginners this could be an issue. (But if you can't get the depth because of the guide you may have to buy a larger one. I don't know how large of one your router will support but wait until the bit comes to see how it will work length wise)

Ed


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## DrumSteve (Jan 30, 2006)

Bad day today...  

Started good. Printed out jpegs, deciphered them and even came up with some ideas of my own. Then had to go to son's baseball practice (I coach his team). After that went to the store to buy wood, etc for jig/template. Then to Rockler to get some nice knobs, etc for jig. Found stuff cheaper at Rockler so back to big store to return overpriced stuff. Came home, started drawing and cutting wood. Tools went crashing to the floor - bent this and that - totaled nice power tools. Went to store to replce them. Came home with new shiny tools (and less in my back pocket...). Wrong tools. Will have to return and exchange tomorrow. Got online to check status of bits ordered. Website says "credit card approval required" so shipment wasn't sent out. Much too late to call.

Deadline for these drums to be finished is 10 days. Not a good time for all these set backs :'( And all I wanted to do was to improve on my design and speed up the process of cutting the top.

But tomorrow's another day. 

And things will come together, right?!

Sorry for the lament if anyone cared to read this. Just had to get it out.

Steve


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## template tom (Sep 18, 2004)

reible said:


> Hi Steve,
> One other trade off is as the guide bushing gets larger the larger the template cut out becomes and at some point the router will only have the sub-base sitting on the edge near the contact point, the other side will be over the cut out area so you can get tipping happening....... as you do this more it isn't so bad but for beginners this could be an issue.
> 
> Ed is correct
> ...


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## reible (Sep 10, 2004)

DrumSteve said:


> Bad day today...
> 
> Started good. Printed out jpegs, deciphered them and even came up with some ideas of my own. Then had to go to son's baseball practice (I coach his team). After that went to the store to buy wood, etc for jig/template. Then to Rockler to get some nice knobs, etc for jig. Found stuff cheaper at Rockler so back to big store to return overpriced stuff. Came home, started drawing and cutting wood. Tools went crashing to the floor - bent this and that - totaled nice power tools. Went to store to replce them. Came home with new shiny tools (and less in my back pocket...). Wrong tools. Will have to return and exchange tomorrow. Got online to check status of bits ordered. Website says "credit card approval required" so shipment wasn't sent out. Much too late to call.
> 
> ...


 Sounds like you just had "one of those days". Hope things are better today!

If you have a deadline then you might want to revisit if this is the best time to play with the router business.... you will most likly have a learning curve and getting everything set-up and working can be little more involved..... I might think a simple jig with the cutout and screwing it to the inside of the tops might be a good way to start before going to the elabrate jigs.... you can tack a stop on the template for the position of the beginning and ends of the cuts....

Anyway best of luck on the project!

Ed


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## DrumSteve (Jan 30, 2006)

Much better day today. 

I've actually been thinking of little else besides this jig... my wife just rolls her eyes every time I open my mouth because she knows exactly what's going to come out  

Anyway, Tom as I read your post just now, I had another thought to change my design some to include a support in the middle. But I'm guessing that the smaller the better to keep chips from getting bunched up in there. So, I've just modified a part that I spent the little evening I had building  That's okay, though; all part of it, I guess.

And Ed, you're right about taking it slow - don't want to spend all my time with the jig when I need to get the drum done - good news is that I have to wait a few more days for the router bit to arrive before I can do the cutting. Maybe I can get the jig done by then.

This is surely something I'll be excited to show off with some pics; hopefully won't be too boring for you all 

Night,

Steve


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## karincorbin (Nov 9, 2005)

DrumSteve said:


> Hey everyone,
> 
> I'm a new guy here with a dilemma of sorts. I'm trying to make a cut the shape of a U bolt 2 3/4" wide, and ranging from 7 to 10" long. I'd like to use a 3/16" bit, but the padouk I'm routing is 3/4" thick, so the smallest I've found is 15/64.
> 
> ...


Cutting the grooves is a good job for a pin router setup. Veritas sells an overarm pin for router tables. I am assuming this drum will be a production model you plan on selling. If you make the pin and pattern groove width the same as the finished size of the U slot you can cut the depth in several stages with a half inch long bit. The first passes have the pattern adhered to the drum part. After you have reached maximum depth remove the pattern. Then flip the drum part over and use the groove you just cut as the pin guide and finish cutting through the part. Make sure the bit height is adjusted so it does not hit the pin. 

Aligning the pin and the bit is fairly easy. Use a short length of K & S brass tubing with an inside diameter of 1/8". I am assuming that is the diameter of your cutter and your pin. Slide it over the bit, lower the pin into it, (power off) and tighten the clamps holding the pin arm. Remove the piece of brass tube. K & S brass tubes are available in a wide variety of sizes at most hardware and hobby shops. They are made to be telescopic with each other so there are tubes with the common fractional inside diameters. If you are very clever and good with silver soldering you can make these tubes into miniature router guide bushings to use with Dremel motors and laminate trimmers for precise inlay work. 


Getting your pattern made from a drawing by laser or waterjet cutting cost a few dollars but it will be accurate. Make extra patterns if you are doing production runs so you can batch process parts.

Karin


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