Homemade lathe for metal and wood

I am in the process of hand building my own lathe that will be capable of turning metal or wood. The spindle will be belt driven using an electric motor from a salvaged, but fully operational, treadmill. The motor has a "flywheel" ( don't know the real term for it) that is approximately 20" in circumference (I'll call that the O.D.) and a smaller (I.D.) that is roughly 7.5" circ. The I.D. has grooves that the belt seats into in order to spin the treadmill belt that one would walk on. The motor maxes out at 6200 rpm.

I want to cut (by hand) identical grooves into the O.D. which is currently smooth. By Cutting these grooves, I'll be increasing my potential spindle speed more than x2.5. Because it's a treadmill, and all the electronics are operational, I will have full control of motor speed, thus spindle speed.

What tool do I need to use to cut these grooves and how do I get one? Or is this a fools errand?

Not sure if you are having a lend with the motor but what are you trying to achieve? Faster? More Torque? What is the power rating of the motor? When you say circumference are you meaning circumference or diameter? I am picturing the smaller diameter as a boss that sticks out and the belts go on. 6000 rpm is very quick to start with. How are you planning on reducing your speed if you plan to cut steel?
What diameter steel and wood do you intend to cut?

Suggest maybe a bit more work on the design.

As far as cutting belt grooves what profile? Vee? Might be best to get someone with a lathe to do it...

Mick




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the ~1500-2000 maximum rpm you will get from the stock treadmill pulley arrangement should be enough for you until you know what you're doing.

you don't need grooves on your spindle pulley, you can tension the belt tight enough to stall the electric motor without overloading it without grooves on the spindle pulleys. just run the belt in the original motor pulley and you may even consider re-using the original (plastic?) pulley that drove the treadmill belt, bore it out and install it in the spindle. if you do that you can reduce the tension on the belt by a factor of about 2.

NCGoodman said:

I am in the process of hand building my own lathe that will be capable of turning metal or wood. The spindle will be belt driven using an electric motor from a salvaged, but fully operational, treadmill. The motor has a "flywheel" ( don't know the real term for it) that is approximately 20" in circumference (I'll call that the O.D.) and a smaller (I.D.) that is roughly 7.5" circ. The I.D. has grooves that the belt seats into in order to spin the treadmill belt that one would walk on. The motor maxes out at 6200 rpm.

I want to cut (by hand) identical grooves into the O.D. which is currently smooth. By Cutting these grooves, I'll be increasing my potential spindle speed more than x2.5. Because it's a treadmill, and all the electronics are operational, I will have full control of motor speed, thus spindle speed.

What tool do I need to use to cut these grooves and how do I get one? Or is this a fools errand?

Click to expand...

Yes it is a fools errand. Right from the get go. There are 1000s of lathes available, why build one? A massive amount of work for what? A machine of questionable usefulness and no resale value. Why waste time reinventing the wheel?

Fine Woodworking magazine (issue about 20 years ago) had a article about hand built wood lathes. Pretty cool.

For making a metal lathe, .... fools project.

Unless it's a really highend/HD treadmill, I wouldn't bother using it for anything like a lathe. Most of the treadmill motors are rated for a higher voltage than they actually run at so they never really achieve the "2 1/2 HP" on the motor plate[130 vs 90vdc]. You will likely be underwhelmed. I have seen some with a Baldor 1 1/2HP, 90vdc motor. Those might be worth saving for a small/bench lathe drive, but as others have said, don't build the lathe, buy it. JinNJ

Please take qty (5) minutes to READ the posting guidelines, especially the ones in the proper
area (the general area).

Well in response to some of your replys:

My apologies for probably posting in the wrong area, this is my first time posting on any forum.

My mission is not to re-invent the wheel, I'm don't have the monetary means to afford a lathe, but I have a love for the art of turning wood or metal using tools that are hand held.

I'm not intending on using the original pulley set up, or the original belt, but I figured the "V" grooves in the original belt would be popular in design, so when I get a new belt, the same pattern would be probable.

I have experience in CNC metal lathe work and those machines turned at ~20k rpm. Now I understand, those are computer controlled, and way more precise than I could ever be, it just caused me to believe that a higher rpm was needed, and this is how I was planning on achieving that.

Yes I meant circ, not dia. I can reduce speed from the control panel that is fully functional. I have already dis- and re- assembled it a few times to make sure I didn't mess it up and learned how to make adjustments needed to convert this to a small hobby lathe.

Materials I'm considering include copper, aluminum and wood,... maybe some steel, but I'm ready to jump to steel yet.

This is just a project for the workshop in the backyard, not for a business workload.

Again, I'm sorry if I've posted this incorrectly, when I Googled "metal lathe forum", this site was near the top of the list, so I came ignorant and looking info/help. I didn't want to plug in my "franken-lathe" and lose a hand or worse.

I thank you in advance for any helpful information and guidance, but if your intent is to demean me for my creativity or lack of expendable income, I would appreciate it if you would not. I'm untrained and poor, but very intelligent, good with a wrench, and my wife says I need a hobby lol

NCGoodman said:

My apologies for probably posting in the wrong area, this is my first time posting on any forum.

I thank you in advance for any helpful information and guidance,

Click to expand...

This forum is definitely geared to the professional machinists. Talking about making a lathe from scratch is a forbidden topic here per the forum owner. What you need is to frequent a hobby forum more suited to your desires.

The Hobby-Machinist

'walks over to the wood pile throw another log on the fire'that is this post.
You can not hold a hand held tool nearly steady enough to form a chip like that using a chisel in wood. I can not see how you skipped over the important part bed rails and ball screws, if you once a upon time ran a cnc lathe. Take a job at a hot dog stand and save up 60 hours of minimum wage. go to harbor fright and buy there unmentionable.

The grooves you speak of are that of timing belt and pulleys. Normally sold preformed, you could machine on a mill. A v belt will transfer all the hp and torque you will produce.