ideal lathe question

[curtis rosche]

so if you could desing your own lathe. specifically for turning bowls and some hollowforms, what size would it be? like how long of a bed and how big of a swing?. im looking into building my own lathe for a school project. im thinking of a bed just over 2ft long, and a swing of maybe 25 inches? how often do you find the need to turn a peice large in diameter, or a hollowform that is longer?

also, since it wont be used for spindle i wont need a tailstock for it right? for hollowforms i can just use a steadyrest.

[Reed Gray]

Curtis,
For a dedicated bowl lathe, I would look to pattern one after the VB36. Massive headstock, cast iron, huge bearings, and a 3 to 5 hp motor, and a massive headstock spindle (2 to 3 inches) turned down a bit (1 1/4 or 1 1/2 inch) for the mounting of chucks and face plates. The tailstock is an option, but for novice turners (like a your school), until they learn how to attach blanks so they won't fall or tear off, a tailstock is great insurance.

It is nice to turn big bowls, but it is a specialized market. For anything over 16 inches, you need people who do a lot of entertaining of big groups. Less than 16 inches is more in the family size, which is a much bigger market.

Hollow forms are another thing, and if you are using a captured system (like Lyle Jamison's), you will need an extended bed for mounting the support. Hand held hollowing systems work for forms up to 8 inches or so, but when you get over that, especially for novice turners, it gets much more difficult and risky to control.

I did see a nice home made lathe once. A 2 hp DC motor slapped onto some channel iron, 30 inch diameter, and welded to a 1/4 inch steel plate. Not pretty, but very functional.

robo hippy

[Rob Cunningham]

I have an older Vega model 24 that does not have a tail stock. The newer models all have tail stocks, which I think you would want with a large, unbalanced blank. I've only roughed one 8" bowl on it so far and it wasn't an issue, but I'm thinking of building a tail stock someday.
Check out the Vega website, you might get some design ideas.

[Bernie Weishapl]

Ditto what Reed said. I also would want a tailstock on my lathe for sure. Even with a out of round HF blank or a big out of round bowl blank for sure I would use a tailstock.

[curtis rosche]

Reed, this project would be comeing home with me and be mine once i was done. for a tailstock, since im not drilling holes with it, does it need to be able to move like a normal one? or could it just be a block with a live center at the right height?

as soon as i get the 3d drawings finished i will post them. im looking at using 2 inch square tube steel, and for a spindle using that really big powermatic spindle.

[Leo Van Der Loo]

Why don't you start with a bigger metal lathe Curtis ??
That way you have the headstock and bearings taken care of.
Just build a platform and banjo or buy a big Oneway banjo, and you are all set.
Tailstock is handy, but not really necessary, if you know how to mount it and turn without catches.
Here are a couple of pictures of a piece I'm working on now, that about the size you want to turn ?? :), started at 31 inches

[curtis rosche]

yeah thats the size i want to do. ive explored that option of an old pattern makers lathe or mtel lathe. there wasnt much around me.

2''x2'' square tube steel 1/8 thick should be strong enough right?

[Dave Ogren]

Curtis,

I think that Reed and Leo are both right. I have a VB36 am extremely happy with it. I have had no problems with larger out of balance blanks. I usually use an 8" face plate with 6 #14x1" SMS. zero problems. The VB spindle is not threaded, which I like even better. They call it a "Bayonet System" Similar to a cam lock on a toolroom lathe. It would be very easy to duplicate, no threads. I believe they now offer a 3 horsepower option.

I can give you all of the details if you want. The bigest thing is no bed in the way. Good Luck.

Dave

[curtis rosche]

i am working on a drawing , im using the specs of a pm 4224, using the spindle height and width. i have a pm spindle. im thinking of a 2- 2 1/2 ft bed. with a 36 inch swing.
can i see a picture of the "Bayonet System"?

[Leo Van Der Loo]

Curtis if you do want to go big, forget about the tiny steel pieces and existing lathe shafts.
You don't use chucks, but faceplates, a big shaft like 3" thick or better with a small trough hole for a draw-rod, say 5/8" and machined out on one end for a MT #5 or #6 and this shaft held by self-aligning bearings in housings that are bolted to a big piece of concrete.
A faceplate with MT end on it you can screw to a blank you want to turn, you slide the blank with the MT faceplate into the spindle and tighten with the draw rod and away you go.
To remove you use a wedge setup like in a drill-press with a shim to loosen the faceplate and remove your completed turning.
You do need to setup a toolrest that is big and stable to hold your turning tools on.

Have a look at what Vernon Kleibrant uses for some more input, it should give you some more ideas, just don't be to much in a rush to do this, you better think this over carefully .
Cast iron or concrete would be the better over steel tubing, 2" doesn't begin to cover it IMO.
http://www.vkleibrant.com/process.html

[Reed Gray]

Curtis,
I would think you would want a movable tailstock. If not, you could make a tilt away one, but you would need a long tailstock cranking spindle (12 inches or more) because some times you might be turning platters, and others, you might be turning deep bowls. Better plan it so that you can get it into a pick up, or on a flat bed.

robo hippy

[curtis rosche]

Leo, i wasnt think of doing a huge lathe. i think 35 inches would be about max size. i dont have much that is bigger than that except maybe a tree stump, but i dont think i would turn that.

the reason i am thinking about steel tubing is so that this thing can be easily moved for the school project. the regional competition is at a university, the state one is about 3 hours away, and the national competition is in baltimore. once the competition is done, i will bring it home fill it in with concrete. i dont have to actually use it for the competition, its more of a design and build thing than a make it work type competition.

[Leo Van Der Loo]

Curtis in order to turn a 3 foot lump of wood, you do need a very heavy lathe.

Have you ever seen a unbalanced tire/wheel shake a whole car, ??, and it takes only a couple of small weights to restore the balance, a big piece of wood is going to shake your whole house, and I'm not kidding.

But for a design competition you could weld a framework of steel pipes with the bearings and shaft bolted and a motor hung onto it, you could then later fill that in with sand or concrete if you would weld some plates onto the frame later when home, or you could do that now already, yours to decide

[Dave Ogren]

Here is the Bayonet system

http://www.hegner.co.uk/pages/VB36_Lathes/Designers_View/designers_view.html

I sure hope I did this right.
I can give you all of the measurements if you need.
Leo is right about the machine having to be heavy duty.
The base VB36 is only 585# but is also bolted to the floor.
Scroll thru this web site and I feel you will learn a lot. The spindle diameter is almost 2 1/2" in diameter and sleeve bearings are better and less expensive that a similar sized ball bearing. I think that the bayonet system flange would be easier and less expensive to make than the Morse taper. A Morse taper to work properly has to be ground to a micro finish of 32 or better. One on the key things that tells you heavy duty, is the owners manual says that the owner should have a hoist with a lift capacity of at least 2,000 pounds.

Hope this helps and Good Luck.

Dave

[curtis rosche]

i have drooled over the VB36 for a long time. i found pillow bearings for $15. how well will these work?

Leo, i will fill it in with sand or cement when it is all done.

[Nathan Hawkes]

Curtis, it depends on how big the shaft and bearings are. I have to agree about the square tube--not even close to big enough. Think heavy--very very heavy. My 3520 is balanced and still will shake & walk even with over 400lbs extra--that's 1100lbs with the bed extension on it, and I'd be happy if it weighed twice as much, or had a bed that was even stiffer. Things flex when you subject them to big centrifugal force loads. Offcenter or out-of-round turnings are pretty amazingly vibration-prone. There is a series of harmonic frequency vibrations with just about any piece that isn't perfectly round. Mass just tends to dampen these vibrations. The thinnest metal in fabricated lathes I've seen is 3/16", and that's on the stand pieces. The bed way stiffeners I've seen are 1/4" or 3/8" thick, and the tubes are 1/4" wall or better.

I have a friend with a homemade lathe that is pretty amazingly stable--not what I'd call pretty, but man is it functional. The spindle shaft is close to 2" diameter, turned down to a 1.5" thread, and adapters to different faceplate sizes. No tailstock, but its more solid than my powermatic. It has very wide splayed legs, and probably weighs in excess of 1000lbs. The only OneWay (a 2436) I've seen in person & turned anything on will vibrate with an out of balance piece just like anything else if you turn the speed up too high, and it had every possible outboard attatchment and weighed well over 1000lbs. Heavy is good. Patternmakers lathes and larger metal lathes weigh many 1000's of pounds. I wish I had the space for something like that. I saw an old Oliver 20 that went for a couple thousand bucks (needed LOTS of TLC and restoration, new bearings....). I'd love a few thousand pounds of old American cast iron, not to mention the truck & trailer it would take to tow---something like 13 feet long.

[curtis rosche]

just for drawing purposes i am going with 2x2 steel. i havent checked the prices at the local weld shop yet to see what i can get. i have checked craigslist for stel but didnt come up with much. but i did find a couple metal recyclers who are willing to let me know if they come across anything good. if i can figure out how to upload the 3d drawing i will do it today.

[curtis rosche]

lets see if it will upload my drawing. nope, it wont let me. how do i upload it? do i have to take a picture of it first?

[curtis rosche]

heres the drawings i have made so far. this is drawn using 2x2 tube steel. hopefully i will get a chance to get down to the weld shop and get some prices.
the bed is an I-beam with angle iron welded to it.

[neil mackay]

The ideal lathe, Hmm, bit of a can of worms I suspect. But here goes, for me I like different aspects of many lathes and seeing that I have built a couple of my own.
I have broken them down into two categories, one is a short bed big diameter ie 2.5' bed with a max bowl size of 30''+ no tailstock, on this I have my Longworth chuck of 2.5' dia.This I use for finishing the bottoms of bowl,platter etc. Lathe two has a longer bed an d can turn up to about 4' in length, max dia also around 30'' it will have a tailstock.

Some where in the middle of this I have an old Woodfast 400 which I am rebuilding to have a 3 phase variable speed drive, a kick stop bar like the Vicmarcs. I will be leaving the 4 step pulleys in place and up the motor to 1hp from its original 1/2hp.

I have on the drawing board a new design incorporating most if not all the features of the ones above plus a bit more

[curtis rosche]

so is my design any good?

[Dave Schell]

Curtis, great drawings - looks like it is going to be a great project and a lot of fun to build. One question, the total height of the lathe is 48" and your bed height is 24". That means the height of the spindle over the bed is about 24" as well. So a total turning capacity of 48"? That seems a bit out of proportion to the rest of the construction of this lathe. I think you probably want to reduce that spindle height to more like 12-13" for a 24-26" total capacity.

Also, it looks like the base on your design could hold a lot of ballast - a good thing.

What is your budget for this build? Remember Mark Norman's concrete build documented on the creek? He seemed to take a somewhat budget route and still had about $1200 in it before he was able to finish. Just a caveat - the things can add up pretty quick with the motor, drive, spindle, etc.

Wish you the best of luck - keep us posted on your progress.

[Rob Cunningham]

Curtis,
It looks like you are on the right track with the design. If you enclose the base under the motor/ headstock area, you could add a lot of ballast. Basically a big sand box.
The only thing I see as a possible problem is the "Y" shaped support that runs along the floor. Would this be in the way of your feet if standing near the headstock end?

[curtis rosche]

i went with that size swing because i think it would be easier to start with it big, than to make it smaller and wish it was bigger. what would be some potential issues to the swing that i have right now?

Rob, i was thinking about that, but i dont think it will be to much in the way, and if it is, i can always cut it off and fix it. i will look into that when i start going over it today

as for a budget. this is an extremly low budget build. i already have a motor which i got for free. 2 pillow blocks are about $25 plus shipping. spindle is $20 plus shipping. welding is done for the rate that the guy at the weld shop chooses, which for the 2 hours i was there last time cost me about $2.50 since i was doing the work myself.
the only unknown right now is the cost of steel. i will get that this weekend. it should be cheap, less than 2$ a foot. im not sure about the cost of the section of I-beam, but i should be able to get it cheap at the junkyard.

the first thing i am going to buy is the steel. even if something comes up and i cant complete the lathe, i can still go to the competition with just a frame and win.

after i get steel prices i will go back and redesign the lathe to accomadate. if the prices are lower than i thought, the steel size will increase to make it stronger.

[curtis rosche]

these pillow blocks will work for this right? https://www.surpluscenter.com/item.asp?UID=2009091109074121&item=1-207-22-P&catname=powerTrans. im not %100 percent sure on the size yet, but it is between 1 1/4 and 1 3/4.

[Reed Gray]

Curtis,
Make a quick prototype with some 2 x 4s and 2 x 6s to see what it looks like and stand around it like you would when you will be turning. Make the front tripod so you can move it to the back and try both configurations. I agree that the Y on the floor may be in the way, and it might be better to put it on the back. Most of the stress and forces will be on the lathe stand, and not on the ways/bed of the lathe. The idea of a tripod for the motor to be on is good, and out the back will allow you space for a sand box for extra mass. I would prefer sand to concrete, as the sand will absorb vibration better, and if you do have to move the lathe after it is in place, then you can drain the sand. Structurally and for stability, you may want a bigger/deeper footprint for the lathe, and what you have looks a bit shallow to me. Side to side is fine.

robo hippy

[curtis rosche]

the motor will have a mount. i just threw the shape of a motor in to help show how it would work, one of my teachers wasnt understanding it.
it is 3ft long . the reason i didnt make it deeper is because the 2 A-frames are the right distance apart for the spindle. i can always make an add on to make it deeper. will printing it out full scale help just as much as a mock up? i dont have the materials for a mock up that is full scale. but when i weld it, i can always just do small tacks, so that if something is wrong i can easily fix it.

[Rob Cunningham]

Making a prototype/mock-up would be better than a full scale drawing IMO. You get the full feel of what it's going to be like. Use anything you have on hand, wood, cardboard, etc. It doesn't have to look pretty.

[curtis rosche]

got plenty of cardboard. great idea

[Reed Gray]

Curtis,
You can use tape or chalk on a concrete floor for the foot print, and any old sticks to make the frame, including cardboard. . It doesn't have to be pretty. I consider a full scale drawing to be as much help as a full sized mock up, especially if it is some thing that you have never built. When some one is considering a piece of furniture from me like a coffee table, I will tell them to put some card board on some milk crates, or boxes in the space where it will go, about the size they want, to help them visualize how it will work for traffic flow and utility. Same idea applys here.

robo hippy

[curtis rosche]

i might ba able to get that done this weekend. gonna be an ugly looking mock up, but it should still serve its purpose.

[Jim Becker]

IMHO, you do need a tailstock to work safely. Many types of forms are started between centers and it's a "best practice" to keep larger items between centers for as long as possible.

My Stubby has one of the most ideal configurations for turning bowls and vessels as well as large platters. And all of this is inboard. The sliding ways create a significant amount of flexibility in that respect while being able to retain use of the tailstock. There is also a lot of flexibility relative to the tool rest positioning...it even comes with two so when you are working with large objects, you can have one off an short auxiliary bed off the headstock and another on the ways.

[Reed Gray]

Curtis,
One after thought about the headstock bearings. Most of the stress and beating will be on the front/inboard bearings, so you want them to be the most heavy duty you can get. I think one company even puts double bearings in the front side of the headstock spindle.

robo hippy

[curtis rosche]

the vb36 has 3 on the inboard side i think. i think that the bearings on that link should do the trick for now though