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Wood Lathe Project

M

mikeplumb

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Nov 28, 2005
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Hi guys, you may remember me from a few weeks ago. I posted a few questions regarding design specifications for a wood lathe, well I am now (in a weeks time) due to hand in the first part of my assignment and have one further question.

If you were to design a small home use portable wood lathe, what material/s and methods of manufacture (cast/ grinding etc) would you use to make the following parts of the lathe?

a) Headstock
b) Tailstock
c) Bed
d) The 'rails'
e) Spindle
f) Saddle

Thanks for your previous help guys, the reason I have asked this is there are some discrepancies between myself and other 'students' methods which has cast seeds of doubt in my mind regarding my assignment.

Mike
 
Although casting would be nice if you had the capability I think welding up angle iron, square tubing and or flat stock would be easier. Ideally you would have a lathe and or mill to make the headstock and tailstock work better but there are ways around this. I've seen several homemade lathes that were simply welded up.
 
Sorry forgot to add, this is not to be a one off, you are designing for a business which has projected 1,000 sales per week the manufacture of the lathe is to be carried out in an industrial workshop.

Mike
 
When I was looking for a lathe one of my criterion was that it would be cast iron. Reason being that cast iron has pretty good vibration damping and is fairly stable. (In my understanding of it of course.)

So I would say that the headstock, tailstock, bed (including the ways/rails) should be a good quality cast iron. I've had experience with bad quality cast iron and that would be worse than stamped out steel....

Of course the spindle should be steel of some sort. I think that would be best for mounting bearings and morse tapers. I'm not sure what qualities it should take, hardened, mild???

As for the saddle... I assume you mean the tool rest and fixture? There are varying opinions on this. Some reason that the tool rest itself should be cast iron so as to break in event of a catastrophic catch. Some would rather not have the tool rest break and make them out of steel....

I would think that the fixture that the tool rest sits in should be cast iron as well. After all this is what the tool rests on, and we're trying to eliminate as much vibration that we can.
 
Yeah, thats pretty much what I have in my assignment though one of the factors is that the lathe ultimately has to be portable and from mt reckoning all this cast iron won't be too easy to lift by the average built operator.
 
Based on research when I purchased my second lathe, cast iron is the way to go. As you know the weight is needed to dampen vibration. For portability, what about wheels for the overall lathe and easy take down of the parts. I don't think you can have both lightweight and untimate functionality.

Ron Wilson
 
My ideal for a portable lathe would be of cast aluminum for weight savings, for all the parts normally made of cast iron--headstock, tailstock, bed, and banjo. I'd have ground steel bedrails bolted on an aluminum bed. Steel inserts would be used in places of high wear--a hardened steel sleeve in the tailstock for the ram, same for the banjo for the toolpost. Of course, the spindle, tailstock ram, and toolpost would be steel.
 
Jet Mini's and Delta Midi's are "ported" everywhere. Can't get much more portable without making it really dinky.

These are the lathes of choice for Demonstrators everywhere. I find that I can tote my little Jet pretty easily.
 
Casting

My 2 cents: For everything on the lathe except for the spindle, cast is the way to go for the following reasons; 1. Stable and vibration dampening, 2. Repeatability of the manufacturing process, 3. Cost effective, 4. With correct machining set up, parts are better standardized.
All other parts can be purchased / out sourced for more cost savings.
This is all based on your facility capabilities. All this would change if you were building one on you own.
 
Mike,

What do you need to be as far as weight, size, etc?

Honestly, a slightly scaled down Jet Mini or little pen lathe would be a model to work from.

Aluminum is nice but you'd have to be pretty high grade before you'd get the stability you want, and I'd be worried about stress fractures from vibrations, since aluminum tempers quickly under flex. Also, you'd still have to bolt it down for anything even a tiny bit unbalanced.

Any place you try to lose weight, you're going to lose strength, stability, and ability to handle stresses.

Now, if all you're going to turn is small spindles that are relatively balanced, you can scale down quite a bit and lose lots of metal, although I'd still say cast or welded iron or steel is the way to go.

Actually, look at the Oneway lathes. The hollow cylinder for the body is a way to keep torsional strength with low weight.

Good luck,
Dietrich
 
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