# Any Interest in Designing a Router Lathe?



## n6vc (Oct 11, 2012)

After reading through and looking at drawings and videos of different router lathes, I think as a group we can design a better mousetrap.
The first thing is to develop a wist list. These are a few of mine:
1. Turn 6' long spindles
2. Use back gears from a metal lathe
3. Use lead screws for the X, Y and Z axis
4. Be able to turn tapers
5. Do decorative spiral cuts
6. Use sprocket and chain to transmit power to the headstock.
7. Use teflon bearing surface for the cross slide.
I already have some general concepts in mind. Back gears from a metal lathe are cheap and eliminate the need to figure the pitch diameters and gear tooth design. They would also make it possible to design the feeds and speeds in a compact configuration. Long distance transmission of power would come from chains and sprockets. Again cheap and available. The "Y" axis adjustment can be controlled using the sprocket and chain. 
The headstock should have as much distance between support bearings as possible. The bearings can be bushings since rotational speed is very slow. One big plus to this is that oval turnings can be done safely. Although designing the headstock to use chucks is possible, this would add a lot of expense to the project.
The tailstock will need to adjust in height for turning tapers.
I have started drawings to present to the group.
Your thoughts would be invaluable, if there is any interest.


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## neville9999 (Jul 22, 2010)

n6vc said:


> After reading through and looking at drawings and videos of different router lathes, I think as a group we can design a better mousetrap.
> The first thing is to develop a wist list. These are a few of mine:
> 1. Turn 6' long spindles
> 2. Use back gears from a metal lathe
> ...


Have a look at the "Router Turning" Thread by "Dick in ia". It is in Jigs and Fixtures, there are pages and pages about Router Lathes there, and the answer is, "Yes", there are a few of us making Router Lathes and you are free to join the conversation. NGM


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## elrodqfudp (Sep 5, 2011)

I also think that Dick's router lathe would be a great starting point. Why invent the wheel twice when we only need to improve it? 

What would be the advantage to using chains and sprockets over wood gears? 

Back gear could be accomplished with a planetary gear set. I would be glad to assist you , if necessary, in the design. With two planetary sets you could have three speeds and a very low reverse.


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## n6vc (Oct 11, 2012)

elrodqfudp said:


> I also think that Dick's router lathe would be a great starting point. Why invent the wheel twice when we only need to improve it?
> 
> What would be the advantage to using chains and sprockets over wood gears?
> 
> Back gear could be accomplished with a planetary gear set. I would be glad to assist you , if necessary, in the design. With two planetary sets you could have three speeds and a very low reverse.


I agree that Dick's lathe makes a terrific starting point! What I am trying to accomplish is developing a set of plans that anyone can use to build their own lathe without the intricacies of cutting wooden gears.
I didn't think about using transmission parts. That's a great idea! An old powerglide transmission could provide the planetary gearset.
One design goal is that actual metal working be kept to hacksaw and drills.
I'll have the base plans pretty quick that can begin the critique.


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## n6vc (Oct 11, 2012)

Here is the Router Lathe Base. Let me know your thoughts and corrections.


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## Clemo (Jun 9, 2012)

*There is another way.*

Thank you Jon for starting this second Router Turning thread. There is a reason for "redesigning the wheel", if there is another wheel, and there is in this case.

I intend writing two posts with photos, firstly on the proprietry lathe that I have, sold round the world under different names and without any gears. Then on the small DIY lathe I am developing right now.

I'm told by others that the quality of this lathe is poor, the indexing is limited, and the spiral work is inconsistent.

In my experience, I have turned legs for a billiard table and I have turned billiard cues consistently and reliably. I have turned barley twist, right and left hand. I have turned 2, 3, 4 and 5 flute hollow helixes to outside diameters between 60mm to 140mm.

The chuck is 120mm I.D. but the router bridge permits a throw of 70mm, giving a max diameter for work of 150mm (6"). The working bed is 1100mm or 3'-6". I see Jon that you suggest working to 6'. With my lathe I can turn a very good (round) tennon on the end of one piece and I can drill a good hole dead centre in the next. So a 7ft rest (cowboy stick) for a billiard table set, made in three parts and glued, with two 3" deep mortise & tennon joints works fine. Similarly, a mortise & tennon the the middle of a 6' standatd lamp is invisible, all done on a 3'-6" lathe.

The spiral turning process relies on a wire cable passing round a pulley at the chuck. My lathe has three pulleys giving 200mm (8"), 150mm (6") and 130mm (5") pitch spirals. Hollow helixes need longer pitches than barley twist for the same O.D. but in practice, any of this work just looks great. I have thought long and hard about making this lathe chain drive, incorpotating a pushbike cluster to give 8 or 10 pitches, and managing a reduction in the rightangle drive. The importand thing is positive sprocketing or gearing on the chuck and no stretch along the track.

All that is a lot of engineering. When you see my DIY lathe in the next post you will see that it uses chain in this application. I'm now leaning toward a multi pulley wheel on this lathe driving a loop of small chain in lieu of the wire cable. I have made chain drives before (for clocks) and think that I can do it using kitchen cutting board material. Very much a thought in progress. The attraction of chain in this situation is that I can get positive grip on very small diameter pulleys, without relying on tension to deform a bowden cable wire and pull it tight onto a pulley. And small diameter pulleys give short pitches. A second attraction is the chance to play with variable pitch screws, but you will have to wait for next post for that.

Oh, and I have set it up as a copy lathe as well. A bit of a challenge but 30 turned posts like a balistrade. Needs work though. The shortfall in that case (and perhaps this lathe) is that the cutting occurs on the end of the router bit, the bit plunging into the work. On my DIY, the router bit does copy (& round turning) work by cutting on the side of the bit. This gives a much better finish from the lathe, requireing much less sanding to get a high gloss polish. But, that said, there are ways of getting round that problem also.

Check out the pictures.

And just a paragraph on DIY geared lathes. I have cut and lapped gears before. I have nothing but admiration for those that have built any wooden geared machines. As for me, if I cut wooden gears it will be for wooden clocks and I'll hang them on walls for people to marvel at. There are less gears in a wooden clock than there are in a lathe if you manage pitch with cog sets, and especially if you plan on reversing. There are years of work in some of the suggestions I have read in the other post. That's not to say that anyone shouldn't start building their dream. But, for me, there is another way. I've done it, I'm doing it. Before getting into that big a project, have a look at these pics and think carefully, do you want to make things or do you just want to build a lathe? A bit negative, I supose, but thats my opinion.

Tks 4 reading,
C ya,
Clemo.

Don't teach me, for I may not learn, share with me, that we both may learn.


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## Clemo (Jun 9, 2012)

*Part 2, the DIY router lathe.*

I make handles for crochet hooks, I've posted in the past 'bout them.

I make them on the DIY router lathe shown below.

I don't use a router, I use Dremel bits in the handle of a Dremel flex drive. The Dremel itself hangs on a stand on the bench. The hand piece is mounted in an adjustable tool holder, which runs along a square track. The track pivots at the far end to bring the tool into and away from the work.

The work is held in a chuck of my own devising. Its a 50mm (2") pipe end cap, partially filled with resin. There is a 5/16" tapped hole through the centre and the resin provides extra thickness for the threaded rod with lock nuts front and back. Around the perimiter of the pipe end cap I have drilled and tapped 6 holes giving either a 4 jaw (0, 90, 18, 270degrees) or a 3 jaw chuck (0, 120, 240degrees). The chuck is carried on a piece of 5/16" threaded rod which passes through the headstock and is held by bearings front and rear. The bearings sit just in carefully drilled holes.

The tailstock is a similay arrangement but it slides on the "bed" which is housed into a good slab.

Taking square stock to round I get best results using the "side" of the router bit across the top of the work. Make the pass, turn the work, next pass, turn etc.

I intend setting up the copy track to use the router bit in this fashion. And I get perfect, predictable tapers by wedging the tailstock end of the base slab with a chisel. (I tend use vernier calipers and micrometers a lot.) I'll make milk bottle bolts for that one day, but for now its a chisel.

For splines I attach a wheel with a chain behind the headstock. The chain turns then goes along to the tool holder. As I push the tool holder with one hand I keep tension on the chuck with the other. I have a method of indexing using a block against the bolts through the chuck which gives me three or four flutes.

Straight flutes are easy. I set up the tool on the centre line then slide the tool carrier along its rail, advancing the rail closer to the work each pass till I get the depth I want.

With my crochet hook handles weight, balance, finish and size are important. I'm working between 12mm and about 18mm O.D. and a bit longer than a pensil. I make them hollow for weight saving, then cut flutes in the back part to get the balance. And the flutes, especially the through and hollow helixes really look good.

And finally, I'm experimenting with variable pitch helixes. There is a pic below with the chain wheel drilled off centre. A flute goes out of sight by 150degrees of rotation. So, by drilling the wheel way off centre the flutes have a gentle kind of wave in them. Still developing that stuff, but, if you want to do it with gears I'll find the web site for square gears for you.

Tks 4 reading,
C ya
Clemo.

Don't teach me for I may not learn, share with me, that we both may learn.

Its very late, I'll edit this another time.


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## n6vc (Oct 11, 2012)

Hi Clemo,
Lots of great ideas here. I especially like your home made chucks!
On your chain drive, is there a pin to give a positive pull on the dremel slide? I wouldn't think there would be enough contact on the drum to give a positive pull.


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## Clemo (Jun 9, 2012)

If you look at the variable pitch chain pic, one end of the chain is screwed to the white poly wheel. There is a hook on the tool holder. The chain is fixed to the white wheel.

Tks
C ya.


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## brucenelson (Jan 7, 2012)

Concerning chains instead of gears to provide different ratios. Bicycle chains are not good candidates because you cannot turn corners (such as converting linear movement into rotational movement). My suggestion is to use ball chains. I located a supplier of ball chains that could supply ball chains made of stainless steel with 1/4 inch diameter balls. This chain has a tensile strength of 175 pounds, which would be strong enough to provide a positive drive.

The chain that Clemo is using on his crochet hook machine is able to turn a corner and convert linear movement into rotational movement, but does not provide a means for a positive toothed drive, which would be necessary for different gear ratios.

I would suggest a ball chain that would provide a positive drive, similar to gear teeth, and yet turn corners and change linear movement into rotational movement. Also, could provide different ratios by making pulleys out of plastic and having the chain groove incorporate spherical indentations for the individual balls to locate in, thus providing a means for ratios, similar to gear teeth.


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## BRAVOGOLFTANGO (Oct 11, 2012)

Not so much the router/lathe version, but I did throw together some rough-draft plans for a drill press lathe for my new drill. I'll make a separate thread though out of respect, interesting thread here though.


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## n6vc (Oct 11, 2012)

brucenelson said:


> Concerning chains instead of gears to provide different ratios. Bicycle chains are not good candidates because you cannot turn corners (such as converting linear movement into rotational movement). My suggestion is to use ball chains. I located a supplier of ball chains that could supply ball chains made of stainless steel with 1/4 inch diameter balls. This chain has a tensile strength of 175 pounds, which would be strong enough to provide a positive drive.
> 
> The chain that Clemo is using on his crochet hook machine is able to turn a corner and convert linear movement into rotational movement, but does not provide a means for a positive toothed drive, which would be necessary for different gear ratios.
> 
> I would suggest a ball chain that would provide a positive drive, similar to gear teeth, and yet turn corners and change linear movement into rotational movement. Also, could provide different ratios by making pulleys out of plastic and having the chain groove incorporate spherical indentations for the individual balls to locate in, thus providing a means for ratios, similar to gear teeth.


Hi Bruce,
I've never run into an application that used ball chain. just goes to show a person is never too old to learn. 
Do you have an example you could share. I'm definitely eager to learn.


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## Clemo (Jun 9, 2012)

Bruce, tks for the reply.

I have different pitches in my splines with bathplug chain. The pitch is goverend by the diameter of the wheel behind the headstock. The circumfrence of the wheel equals the length of the pitch. The end of the chain is screwed to the wheel so there is a one to one ratio between wheel and chain.

I achive forward and reverse splines by turning the wheel over so the chain winds on the other way. 

I spent time on a second wheel with a chain and weight to provide tension but found it redundant. I just hold the chuck with my left hand while advancing the tool holder with the right, keeping the chain taught.

On bike chain, you are right, it don't bend sideways. I'm experimenting now with chain like you find under cookoo clocks. I'm looking for chain that will comply with small diameter (10mm / 5/16") wheels. The SWL of the chain is unimportant, so long as it doesn't stretch.

Its worth noting that I don't turn barley twist on me little DIY unit. I've not turned more that about 450degrees. I've turned barley twist on my large unit though.

Tks
C ya.


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## elrodqfudp (Sep 5, 2011)

What is so hard about making wooden gears? The first one may seem difficult but after that they are easy if you use the right method. The challenge is half the fun. If you must use chains and sprockets you can make your own. I use a program from 'woodengears.ca'
that is easy to use.


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## n6vc (Oct 11, 2012)

elrodqfudp said:


> What is so hard about making wooden gears? The first one may seem difficult but after that they are easy if you use the right method. The challenge is half the fun. If you must use chains and sprockets you can make your own. I use a program from 'woodengears.ca'
> that is easy to use.


Hi Browne,
It's nice to meet you. The big objection I have with wooden gears is that it is extremely difficult to make small ones that operate smoothly. The spur gears used for metal lathes are cheap and smooth operating. With the software I have and a copy of Machinery's Handbook I can develop whatever pitch diameter and number of teeth I want. Cutting them is another story. This is just my opinion.


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## brucenelson (Jan 7, 2012)

elrodqfudp said:


> What is so hard about making wooden gears? The first one may seem difficult but after that they are easy if you use the right method. The challenge is half the fun. If you must use chains and sprockets you can make your own. I use a program from 'woodengears.ca'
> that is easy to use.


I would like it if you would upload some illustrations of your work making wooden gears with the computer program that you mention.


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## n6vc (Oct 11, 2012)

brucenelson said:


> I would like it if you would upload some illustrations of your work making wooden gears with the computer program that you mention.


Hi Bruce,
Here is the basic procedure for generating the involute needed for the mating surfaces:
Make a Gear circle on front plane (199mm x 19mm)
On the front face of the gear circle, make three circles:
1- 95mm (pitch circle)
2- 90mm (base circle)
3- 88mm (root circle)
create spline with the equations below:
parametric curve equations:
X(t)=R*(cos(t)+t*sin(t))
Y(t)=R*(cos(t)-t*sin(t))
R=35mm
Create horizontal referance line from center of the circle to root circle
Create reference line from center of the circle to base circle, 3.75 deg above horiz
connect involute line to base circle at reference line
give them a tangent relation
mirror involute across horiz ref line
draw lines to extend the lines to root circle (RefLines4 image)

I've only gone through the procedure a couple of times in class, so I am no expert. The instructors were mainly showing the power of using equations to generate objects, in this case a spur gear.
I should use equations in my drawings so they are easier to modify, but I get lazy initially and don't.


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