On my site at http://turningaround.org/4_axis_mill.htm near the bottom is my head stock and tail stock are shown. All off the shelf iteams except for the #2 Morse tapper in the end of the tail stock quill.

Today I worked on doing motor tuning on the indexer axis and it is running great at 300 RPM. Got too involved and didn’t try faster speeds. At this time I don’t see any need for speeds over 100 RPM except when rounding rough stock. At this speed it takes 11 minutes to make 1 pass of 96”. Also I have order a set of laser cut parts and will replace my crappy gantry with the MechMate one.

Art, What were the prices that you paid for these items and what was the source of that you bought them from.

1.25" allthread Macmaster Carr $40 ?
Nuts $20 ?
4 jaw chuck Harbor Freight $16
Live center $95 Oneway lathe
pillow blocks $10?
Machining #2 moris taper $20
I used the Oneway line center because I have a backup one, the Harbor Freight chucks screw on,and the bearings are replacable.http://www.mechmate.com/Forum/messages/19563/3511.jpg

Gerald, If I am to go by your suggested configuration where the gearing ratio changes depending on the diameter of the stock.

I need to work with stocks having diameters ranging from 1" to 12". The RPM's I would like to work with would range from 1-200. Assume that I will have a 3.2 gearing ratio on the motor. How many sets of pulleys and belts will I need.

Sorry, reference to the earlier post my motor gearing ratio is 3.6:1.

Gerald, I did some quick calculations on a worksheet I got done to do RPM calcualtions for the indexer.

If I use a 3.6 geared motor and set the pulsing speed to 45,000 RPM and also if i set the pulley ratio to 1:1.8 (1" pulley on motor shaft and 1.8" pulley on head stock shaft). I would get a indxer RPM of 200 (This i feel should be the minimum for rounding up work on rough stocks).

AS per your theory which says that the pulley diameter should be equal to to the diameter that you are working on then the max diameter of the stock that I can work with would be 1.8" in diamater.

If I need to work on 12" stock (with 12" pulley mounted on Headstock shaft)I can only operate at a max RPM of 30 RPM.

The other option available to me is to do the rounding of the square stocks on a basic turner with no stepper involvement and then transfer the workpiece on to the machine we propose to build.

Fabrica, you are starting to realise to difference between an "indexer" and a "turner"(lathe)...
- indexer turns the work at low speed while a fast spinning cutter (router) takes deep cuts.
- lathe turns the work at high speed, while a static cutter takes shallow cuts.

They are completely different machines. You seem to want an indexer that has the speed of a lathe? With a router driven cutter, the speed of the workpiece can be much slower.

Rough turning in a lathe is good. Sandpapering in a lathe is also very good. Sandpapering on an an indexer is hard work.

I would pick 2 gear ratios max. Probably 3:1 and 9:1. The idea is that you can have:
- direct drive
- 3x slower than direct drive
- and 3x slower again (9x)

Don't pick the middle ratio in the "middle". If your top ratio is 10:1 the middle appears to be 5:1 but that is actually 5X from the bottom and 2x from the top.

It is easy to do this theoretically, but you need to find practical pulleys or gears....

What you mean is that a diference between a indexer and lathe is that the same job that is done on a lathe at high RPM's could be done on Indexers at a low RPM. But for sand papering and rough cutting lathe is a better option.

OK assuming that If I take the indexer path, I already have a stepper with a 3.6 gearing. If I drive it direct the max RPM would be 375, With 3:1 gearing 125 RPM and with 9:1 gearing 42 RPM.

Your suggestion is to do trials with chains and sprockets.

Here is an example of true indexer work. As you will appreciate, the RPM is not a factor when cutting these shapes. And you cannot do them on a normal lathe. To sand them, they must stand still.

This stuff can be done on indexers or lathes. People want to sandpaper them while they spin. Here speed is an important factor.

What I am interested in at the moment would be the second type of machine. Architectural wood coluns does not interest me at least for the moment.

It will mainly be candle stands, stairways, walking sticks etc not exceeding a lenth of 48".

Gerald now I begin to understand. What I have built is an indexer. What is the difference between a 4-axis mill and an indexer? Using 2" stock at 100 RPM it equates to 600 IPM. This would be too fast if I was Cutting with the point of the cutter but it has been my experience that I get a cleaner cut if cutting with the side of the cutter with the cutting edge coming down into the wood (climbing cut?). It is my interpretation that if I use the point of the cutter then for a 2” piece the max rotation will probably be 50 RPM and a 24” piece will be 6 RPM. Side cutting will probably be limited to 12” and less. What IPM range would you consider the max for side cutting? The only time higher RPM's are desirable are when roughing a multi sided piece to round. This is the code I am using, G0 Y96 A1000, for roughing and G0 Y966 A2000 for finish cut and I am side cutting. Is there a better way? On pieces where you can’t reach horizontal centerline to cut the cutting would be done as close to centerline as the tool will reach. This way the tool is still cutting with the side.
The RPM speeds I have used in other posting are in doubt. If I set F200 then Mach posts feed rate at 200 but posts units/minute of 167. What is my actual RPM?
Sanding solution.
Sanding manually is a PIA. A better solution is a flap sander. Here is a version used on the Legacy that could be modified to MechMate. I see it as mounting on the side of Y car with manual Z and XY plane adjustment.
http://turningaround.org/Pugn2.htm

Art, What does PIA stand for. I hope and pray that you meant "Pakistan International Airlines". Most of the Pakistani test Cricketers still work for this institution (Just having some fun on your account).

Art, As I understand The main difference between a indexer and a wood turner is this.

In a wood turning lathe the force to cut the wood is provided by the RPM and the weight of the stock. You need a powerful motor to provide this circular to motion to the stock. This is why you talk about this 1 Hp motor.

In a indexer the cutting force is mainly provided by the router and not by the RPM of the stock. Due to this the machine has the luxury of turning at a lower RPM.

An indexer is a device which can control the exact rotational position of a workpiece. They can stop and hold with minimal backlash.

Fabrica, you say you want to do the "second" type of work (candle stands, stairways, walking sticks etc.). For that you do not need a stepper motor (or MAch3 or gecko) to turn the wood because you do not need a precise stopping position to cut detail. Therefore you don't need an indexer.

The right production machine for candle stands, stairways, walking sticks etc. is a copy lathe, and the MechMate will be perfect to cut the templates (or masters) to use on the copy lathe.

Copy lathe:

http://www.mechmate.com/Forum/messages/2514/3540.jpg

It might still be interesting to use the CNC as the copy device...

Check those out:

link 1

link 2

link 3

Gerald, How am I to do the flutes on the stock. Paco Thanks for your info. I think the machine that you suggest is what I have in mind. How can I get more info on it. I need to mount this on to the mechmate.

Fabrica,

you though about it, I did and so some other did too, but the links I shared are from a talent fellow Botter that share his trial recently. I suggest you do a search on this forum and maybe post your questions directly to Brian. In fact, he might just be reading this thread HERE too...?!

The concept is quite simple; it's pretty much what Gerald post above but the cutter is driven with the CNC X (or Y) and Z axis. You may want to chuck in a 60 deg. V tool bit for final sharp inside corner detailing...

Thanks Paco for your valuble info. I will get in touch with Brian.

The main reason I mention a copy lathe, is for production. In a country where labour is relatively cheap, a copy lathe will very easily beat a CNC indexer for speed, price and ease of sandpapering.

Of course, a copy lathe can be equipped with CNC motors, but then I will put the "gantry" under, or behind, the workpiece so that the operator has maximum access for sandpapering.

No Gerald What I plan to do is to have this thing mounted on the Mechmate parallel to Y axis.

You already said you would do that for making small quantities of samples, and I am not arguing with you. I am simply pointing out some options for mass production.

Fabrica,

Here are a couple more pictures of another Shopboters lathe\indexer.

http://www.mechmate.com/Forum/messages/2514/3552.jpg

http://www.mechmate.com/Forum/messages/2514/3553.jpg

I also will be doing this to my machine at some point.

Good Luck,
Tom

Thanks Tom for your info.

Fabrica
Where are you with your laser deal?

I have received the optics the gun is on the way.

Roughing out
 

Here is a 18" pedistal that I am roughing out. I have to rough it up between each layer glued up because I only have 20" between the rails and not enough Z depth. I am rebuilding the Z with 10" of travel and using a lead screw because of the laterial impact forces involved.

Art, do you use much y-travel when you rough out? Could you do the roughing with the y-car nearly fixed in one position? (say 6" or 4" off TDC). I have an idea for a simple "stabiliser" for roughing out . . . . . .