First cuts on custom indexer/lathe

[JimmyD]

I thought I would share the first two items cut on my newly constructed indexer/lathe combo. This is a Nova Comet II lathe that has been modified with a custom built 18:1 double gear reduction. 12" turning capacity by 55" long. I extended the table rails by 7" to accommodate the indexer/lathe mounting in this location.

The mounting of the gear reduction allows me to use this as an indexer or lathe by loosening and moving the belt on the gear reduction and re-loading the belt on the lathe.

The indexer/lathe is adjustable in height by driving the two jack-assembly under the lathe bed either by a drill or manually with a socket and ratchet. I can have it at a comfortable height to use as a lathe, at the chosen height based on what I am machining as an indexer or move it down completely out of the way to load sheet goods. Four bolts lock it in place. Takes about one minute to change heights.

With this gear reduction I should be able to machine 12" diameter pieces and have excellent holding power when I want to do four sided machining such as a corbel. I was very pleased that I (with some help from some very nice gentlemen on this forum) built this and turned it on and it worked the first time! Now I've got to finish building my table with vacuum and t-slots.

[Brady Watson]

Very nice Jim.

Well done! :cool:

-B

[jTr]

Oh Boy - I want one!
(the lathe, not a 3D copy of Brady's cranium!)

This is a brilliant way to get the most out of a lathe - have you considered teaming up to offer kits for the rest of us? It really is a home run solution.
This is what ShopBotting is all about - thanks for sharing!

Jeff

[Tim Lucas]

Yes, that's awesome :D

I have a lathe in the shop and would love to set it up like that!

[JimmyD]

Thanks to all for all the comments. A "well done!" from guys of your caliber is worthy of putting on a plaque and hanging it where all can see. :)

Jeff, no I hadn't considered making a kit, but anything is possible for the right amount of money!

[scottp55]

Looks Sweet and well done:)

[919RickR]

Very innovative! Great Job!!

[JimmyD]

I wanted to give specific thanks to those that helped me with this. Brady Watson for excellent advice/guidance and most of all Gary Campbell for his innovative and very well done gear reduction. Gary designed and built the gear reduction and supplied the electronics to get to this point. I couldn't have been successful without their great help.

If you have questions about the gear reduction assembly please contact Gary at:

Gary G Campbell
caseworxmfg@gmail.com
(919) 356-3910

Here's a picture Gary posing with the gear reduction!

[Brady Watson]

Jim,
Glad you got it sorted out. Thanks for saying 'thanks' :cool:

The real 'payback' for me is seeing your work. I can tell from the things that you've carved that you've done your homework. It required actual thinking...faith in yourself and perseverance. I'm always happy to see people doing things 'on the level' with this craft, since many sell themselves short or never get into their own stride and figure out what they are made out. Good for you!

-B

[Joseph clements]

What was the cost on the gear reduction and the electronics?

[MogulTx]

Indexer Envy!!!!!!

NICE JOB! ( And with THOSE two helping, you couldn't possibly have an insurmountable problem!!!)

Enjoy it!

Monty

[JimmyD]

What was the cost on the gear reduction and the electronics?

The gear reduction and electronics were a little over $1200. I'm sure that depends on the lathe being modified and the desired gear reduction, etc.

Jim

[Joseph clements]

Where did you buy The gear reduction and electronics?

[JimmyD]

See my post above. Gary Campbell did it for me.

Jim

[jon]

That gear reduction looks great, well done Gary Campbell! I am just wondering if there is any noticeable backlash when you change direction in rotation? Also wondering what the reduction ratio is? I have a few of the old ASM911 motors kicking around, hoping for something in the 100;1 range.

[Gary Campbell]

What do you plan on doing that requires 100:1 reduction?

With the normal loads that are on an indexer, even when used to machine indexed parts, there will be no measureable backlash as long as the belts are properly tensioned. That ratio is 18:1

[gundog]

Impressive work.

[jon]

Thanks for your response Gary. I was under the impression that 100:1 would be ideal for precision and larger diameters. I see now that something between 20:1 and 50:1 will yield good results. I will likely need to make my own larger diameter gears and use smaller manufactured gears since I can't seem to source the appropriate tooth number pulley gears to get a two stage reduction of 20:1 I calculate for stage one with a 24 tooth small pulley a larger pulley of 96 teeth. Then for the second stage with a 24 tooth small pulley a 120 tooth larger pulley. If I have this right then I should get a reduction of 4 x 5 or 20:1
I found some smaller drive pulleys of 12 teeth which I would also get and then would have the option to increase the resolution if desired by subbing them out. I calculate a maximum reduction of 80:1 possible with those.

[Gary Campbell]

Jon...
As with most mechanical things there is always a tradeoff. Reduction is speed vs. torque. If you are going to be primarily cutting rotary wrapped (centerline cutting) type files the diameter to one (example 3:1 for 3" diameter) will keep costs low and be sufficient. If you plan on indexed off center machining then 3 times the width of the part returns enough torque to avoid "jacking" a flat part when cutting. (6 times the off-center distance) will hold just fine. If you use one of the "continuous rotary profile" turning techniques then somewhere in the middle of those is best.

ShopBot offers a few variations of gearmotors with planetary gears in at least 10:1, 25:1 and 50:1. You may find one used for way less effort than making gears that are both consistent and backlash free.

[myxpykalix]

Very cool...you'll find out how much extra creativity the indexer adds to your skills! good job