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Steve Hooper
11-04-2004, 5:54 AM
Good Morning Friends:

This is my first post on this forum, although I lurk on the power tool all the time.

I have not turned for nearly ten years. But when the dual trunks of a 60 foot persimmon tree appeared in my shop drive way, I began to have second thoughts and started to dig out my stuff.

My lathe is an old, old Rockwell mounted on a homemade stand.
It’s driven by a ½ hp 3650 rpm motor through 2, 4 step pulleys.

The trouble is that when I mount a 30 pound chunk of poorly balanced tree trunk on this, it gets very dangerous.

My question is: What type of motor/ speed control do I want?

Thanks
Steve

Gary Max
11-04-2004, 7:38 AM
Steve the best way I know of is a DC motor with a speed controller. I see them on Ebay now and them---if I remember right it was a 3/4 horse with controller for $300.00. You can go down to ---0---rpms on that motor.

Oh

Welcome to the creek

Jim Becker
11-04-2004, 8:35 AM
Most "true" variable speed drive systems used on lathes are either the DC variety that Gary mentions or a VFD (variable frequency drive) controlled 3-phase induction motor...the latter is most common on premium lathes, runs on single phase 240v power and can be assembled relatively inexpensively if you shop surplus. You are right to be concerned about safety when it comes to swinging big and/or heavy material on the lathe. And sometimes even just a few RPM in either direction can make the difference between vibration and no vibration, which can seriously affect the quality of the cut as well as your "comfort" with the operation.

George Tokarev
11-04-2004, 9:44 AM
Not much trouble getting a 1725 motor at half horse, I'm sure. If it's like most of the old stuff, should give you ~500 low end without a countershaft. That's what I turn with, though mine's 3/4 horse. I use the tailstock until things are at their most stable, and have a big particleboard cabinet for my lathe base, so it has a nice low CG.

I can't remember the last time I took the belt off the slowest speed, but a lot of people like the dial-a-turn capability. Had it on my starter lathe, used to think it meant something, then I learned to cut the wood with the tool, and found out speed selection didn't matter to me.

Richard Allen
11-04-2004, 10:41 AM
Hi Steve

A VS drive is a fairly sizable investment for a lathe. A 1 hp half speed motor, as George mentioned, would cost a lot less and likely give you the speed you were looking for.

If you balance the workpiece on a coke bottle you can find a static balance point to start your turning.

Good Luck

Carl Eyman
11-04-2004, 11:47 AM
Does anyone remember the really inexpensive speed controller (mechanical) that consisted of a variable diameter dual groove vee belt pulley. It looked much like a 2 groove pulley, but the two outside halves of the pulley were fixed and the center "divider" was free to move on the shaft toward either side. If one mounted this as a jackshaft between the motor and the load and moved it back and forth so it was nearer the motor or the load the center portion moved one way or the other thus increasing one pitch diameter while decreasing thre other. You could get about a 2:1 speed change out of it. I think it cost less than $25. I used them on packaging machines for years and never remember having to replace one because it was worn out. Grainger used to have them as did McM Carr, but no more. They were good for whatever hp a single vee belt (1/2") could handle. If anyone knows where they are available, I'd sure like to know.

Jim Becker
11-04-2004, 11:56 AM
Carl, a number of lathes use the Reeves drive (variable pulley) for speed control, including the Jet 1236 and similar "design vintages". They work well for the purpose, although really do need to be put at the "stops" to insure that they don't slip faster or slower. So in effect, they are not exactly continuously variable speed if you need to lock them in at specific increments. They also can be dangerous in one manner...you cannot adjust the speed if the machine is not running. Accidentally leaving the tool at a high RPM, mounting a large or unbalanced object and then turning it on could result in serious injury. (Been there...done that...on my first lathe...fortunately, caught it before power was applied and unmounted to correct) One must be careful to habitually reduce the speed to the lowest setting at the end of the workday or end of a project!! There is also a minimum speed for this system. If it's not low enough, it can also be an issue with larger and/or unbalanced object. The typical lowest speed for these systems is 300-500 rpm...far too fast for some of the things folks try to do, IMHO.

You'll really only find Reeves drives on machines that were originally designed for spindle work where they make sense from a cost and functionality standpoint. Modern designs that are aimed at bowl and vessel work have moved very much toward the true variable speed systems that use either DC or VFD drives.

Steve Hooper
11-04-2004, 4:39 PM
I’d like to install a DC motor, but the cost is a bit too much. When I elect to go there, it’ll be a new lathe.

The cost of a new, continuous duty, farm duty motor is about $150.

I like the idea of an idler pulley of some sort.

What about something like the set up used on a drill press?
Has anyone ever done that?

Steve

Wes Bischel
11-04-2004, 10:01 PM
Steve,

I've picked up a number of motors on eBay. This summer I got a 1HP DC motor for a song $20 with local pick-up. The controllers, I picked up a set of 4 KB electronics units NIB for around $25 each. If you are patient and do some homework, the deals are out there. :D

Wes

Carl Eyman
11-04-2004, 10:33 PM
Jim Becker: Right I am familiar with Reeves drives and their forebearers. The one I tried to describe was unbranded and CHEAP, but worked well. I think it could fill a niche today. I tried to fabricate one a few years ago using nylon but it wasn't a success. I haven't had the need to try again lately, but if the need arises I'll give it another shot.

Steve Hooper
11-05-2004, 7:27 PM
Thanks for the input guys:

I found a ½ hp motor to use. I hope it has the power to deal with the persimmon.
Someone else found out I was starting to turn again and gave me an apple tree. I guess I’m back into it.

If anyone runs across a good plan for a speed control I’d appreciate it.

If any of you want some persimmon, come by the shop.

Watch for my garage sale!

Steve

Ted Okolichany
11-05-2004, 8:09 PM
Steve,

How far are you from Cashiers, N.C. If you can bring that big piece of tree to my shop, you can then turn it on my Powermatic 3520A....

Ted

Steve Hooper
11-06-2004, 8:37 AM
Thanks Ted:
You are about 4 hours from Salisbury, which is between Charlotte and Winston.

I have another friend about 6 miles away who has offered his powermatic.

If you would like a block, come on over.

Steve

Ted Okolichany
11-06-2004, 8:43 AM
Hi Steve,

Thanks for the offer on a block from your tree. However, there is a real gloat of wood here as Ivan took down many hardwoods.

I lost a huge red oak, dogwoods, birch, holly, black cherry. Many in the area are in the same boat.

Good luck.

Ted