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Home Made Lathe Question

T

TurningDog

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I am currently designing a big home made lathe for myself and had a few questions. My metal working skills are pretty limited so i will be making most of frame work by laminating pieces of 3/4" BB ply and some simple sheet steel for added strength. I will be using a 1.5 hp dc motor and controller. I can only get the motor down to 50 rpm as is but should be able to gear it down easily enough and I am using the standard spindle from a jet 1642. My big question is how big of a bowl can I safely set this lathe up for if I can gear it down to say 10 or 15 rpm and that size of spindle.

The head stock will be supported on a platform bolted to 4 vertical posts themselves bolted to floor joists and cieling rafters. To further stablize the head stock end I will be making a box around those posts to fill with sand. My preliminary estimates are for at least 7 cubic feet of sand in the base.

My next question involves bearings. I am going to mount the shaft in front and rear bearings. Should I mount it with a pair of pillow block bearings which will be mounted on a few layers of BB Ply or would it be better to mount the back in pillow block and the front side in a flange bearing which will be through a few layers bb ply and possibly a piece of 1/4 or 1/2" sheet steel sandwhiched between them.

My only reason for use the sheet steel would be to give some rigidity to the face of the head stock should I choose to mount ways and add a tailstock. which I am uncertain about doing up front as well. My thoughts on the ways would be to use 2" black pipe threaded into flanges on either end and having some sort of sand filled pedestal at the tail end. I am unsure about how to best make a tailstock at the moment but I think that is a detail that is proably best left until i have the rest of the lathe up and running.

any thoughts?
 
Home made lathes

If you look in my gallery you will see a home made lathe I put together last year. It is crude but probably has the same problems yours will. I use this lathe for rough outs only and have turned bowls as large as 22" by 10". The greatest problem is vibration. I could not get rid of it no matter how much cross bracing I added. I would not bother with a tailstock but it would be nice to get away from a floor stand. I have decided that welding the frame is essential and I am purchasing a welder next week. Now I have a new hobby to learn! I did not fill mine with sand but did have 400lb of sand bags on it. I used pillow blocks and the main frame is made from 6x6 pressure treated lumber. If you have a spindle made use something large. I am using an old oliver spindle which is 1 1/8". I would make one out of 2" stock if I did it again.
Good luck
Matt
 
Hey Dog,

There's a reason why folks tend to purchase an already made lathe. And there's a reason why they cost alot. That reason is stability. Figure that the torsion and lateral stresses you put on a lathe when you spin an out of balance piece of wood (basically all wood) and then apply a cutting tool to it are pretty huge. Without using some serious metal, it's unlikely you'll be able to avoid some bad vibrations (and not the song on the radio in your shop).

I'm guessing that any lathe that uses strengthened plywood as it's structural support is gonna dance a jig when you crank it up. Also, anything down below 100RPM is gonna be tough to turn due to loss of torque and the benefits you get from inertia (body in motion and all that).

I'd be relatively surprised if you can get a stable and functional roughing lathe made the way you've described it. I have, however, been wrong on the rare occasion. All I can say is good luck with it and let us know how it turns out (heh, heh).

Dietrich
 
mkart said:
I would make one out of 2" stock if I did it again.
Good luck
Matt
Click to expand...

I thought about having a custom one milled out until I started running prices with all the local machine shops to get what I wanted. The cheapest 2" which started as a 2.5" piece of stock so i would have a decent collar for the chuck to but up against was almost $200 by the time I had it threaded for my nova titan chuck (not looking to buy a new chuck line and jaws to go with this one), drilled for a draw bolt/ vaccum chucking and and tapped for an mt2. A jet spindle was $55. I am still looking around to see if I can get a beefier or longer one, I was hoping for one out of a nova 3000 but haven't heard back from teknatool yet. I was also hoping to get a spindle from oneway for a 2436 complete with one of their upgraded 96 hole index wheel but they flat out told me if I wanted it for my purpose it would be cheaper to have it made locally, they were kind of rude about it too.
 
dkulze said:
Hey Dog,

Without using some serious metal, it's unlikely you'll be able to avoid some bad vibrations (and not the song on the radio in your shop).

I'm guessing that any lathe that uses strengthened plywood as it's structural support is gonna dance a jig when you crank it up.
Dietrich
Click to expand...

While I may have to change the design somewhat for stability reason I am guessing tieing the whole thing into the structural support of the building and then reinforcing it with plenty of sand should dampen most of the vibration.

The idea of using several layers of BB ply instead of framing timbers came from a turner in austrailia who is an engineer by trade made a long bed lathe (24 ft long to be exact) for turning coopered collums first out of 2x lumber then refining it out of multilayer BB. His was only held down by bags of concrete on and sitting on a concrete floor. Granted his was mounted to railroad ties for lateral stability but I am not ruling out a similar option either.

I am less concerned about the time it takes to turn a large bowl at slow speeds a local turner I completely despise (but I put up with him since he is such a good source of info on parts and turning knowledge knowledge) is using the same motor and controller combo hooked up to a HF lathe bolted to his floor set up for outboarding. He regularly rough and cores 20+ inch bowls with a kelton corer, I tried this out and while the coring took some extra time, finishing a fairly well balanced bowl made from it wasn't too bad and really nice considerring the cost of the system I did it on.

If I would move away from using wood How stable do you think I could make a frame made completely from 2" iron pipe and then reinforced with sand or concrete?
 
Hmmm. 2" iron pipe. Welded? Bolted would work loose over time. Fill the pipes with concrete, maybe? Should work better than wood. Even better if mixed with wood, so's ya gets damping and torsional/lateral rigidity.

Not a lathe build expert here. Just aware of how huge the forces can be that we're working with (a friend walked a 1500lb lathe 10' across his shop floor and took out a support column in about 7 seconds flat).

Dietrich
 
T. Dog,

From a purely statics perspective, the structure sounds solid with the support columns, etc. However, this is primarily a dynamics problem and a very complex one, at that. Having long slender columns from floor to "rafters" (maybe you really mean ceiling joists) does not sound like a good way to dampen vibrations. You may encounter some structural resonances that could shake the heck out of your shop. If you are determined to build this thing, I would suggest using only one grounding point -- and that would be the floor as long as it is a concrete slab. Use plenty of gussets for structural rigidity and come up with a better idea than pillow blocks and flange bearings as these will probably not last very long when attached to a structure that is not absolutely rigid. Looks like time to learn another trade -- metal sand casting so that you can pour your own headstock. Have you considered buying a “basket case†lathe and adapting it to your needs?

Bill
 
I looked around at building my dream lathe, and decided to buy one instead.

The RPMS are ok, you really don't have much tool control at 50 RPMs anyway. Speeds that low are for roughing out and getting the piece balanced.

It really depends how big you want to turn. I wouldn't consider a wooden frame (personally) for anything over about 14" in diameter. You may want to call Bernie at serious lathe and see if he has head castings and spindles around he wants to get rid of. The going rate for a hardened and precision ground spindle and bearing setup I would guess is about $1K. And it has to be fit into a fairly precicion headstock. Or you may look around for a pattern makers lathe that needs rebuilding but has good bearings.

Befriend some welders who can fabricate a base from 1/4" (or larger) plate steel would be a better idea.
 
further thoughts

Since I haven't found a huge wad of cash that I can buy a a oneway 2436 with a 60" extension and the 44" outboard atachment I had some more thoughts on using readily available items to me. I tracked down a lead on a motorless grizzley Lathe with the heavy cast Iron stand for $100. I was thinking about using it with the head turned 90 degrees with my current VS DC Motor setup. This is better than where I am at now in terms of size. But it occured to me to simply weld up a new stand that I could attach to the old one facing the new direction. This still leaves me with tail stock issues but that could be overcome with some work later. I am still going to use a stand alone tool I still have some concerns about the bearings wearing out more quickly but even if I have to replace them once a year it still comes out to be a lot cheaper than the oneway setup I really want not to mention something I can afford now. Hell if it comes right down to it I will buy another HF 34706 and put my dc motor on it and use my tool rest stand, I know people that works well for.
 
I think if you do a little research on Ed Moulthrop you will see that he did quite well with plywood, some solid core doors and angle iron. 🙂

I have the AAW video on Ed, and it is well worth the price.

http://www.woodturner.org/products/videos/video_moulthrop/

Also, there is a great book by Dale Nish called "Master Woodturners" There is a chapter on Ed that covers his lathe and homemade tools.

I don't know if it is still in print, but you may be able to find it at your local library. The ISBN is... 0-934327-00-9

Good luck with it,
Dave
 
more thoughts

I checked out the Griz lathe for sale and not only didn't it run it was beat all to hell. I am afraid it to see what the guy would call poor condition because good condition had noticeable bend in the spindle. However I after looking the Griz lathe over it seems pretty feasible to me to add custome fit cast iron riser blocks and have new bolts made for the cam locks. This also seems like the most financially feasible big lathe option for me as well. I can get a 16" lathe from them delivered for less than $500, I have the dc vs motor and outboard tool stand already and can't see 2 simple casts for riser blocks costing very much. But my question is how tall do you think I could make them and keep the head and tail stocks stable? My thoughts are, atleast on the headstock riser, is I should add some extra length and add a second or third position to lock it down the bed.
 
TurningDog said:
........................ But my question is how tall do you think I could make them and keep the head and tail stocks stable? My thoughts are, atleast on the headstock riser, is I should add some extra length and add a second or third position to lock it down the bed.
Click to expand...


A more important question would be, if the owner of that other lathe was able to bend the spindle, by increasing the working capacity will the head stock(bearings, spindle, casting, etc) take the strain??? 😕 Just a thought.
 
Jake Debski said:
A more important question would be, if the owner of that other lathe was able to bend the spindle, by increasing the working capacity will the head stock(bearings, spindle, casting, etc) take the strain??? 😕 Just a thought.
Click to expand...

I have no doubts about the head stock to handle larger capacity, the bearings will no doubt be the weak point but it wouldn't be the first time in my life I have had to replace the bearings in something. No the problems with this lathe were solely because it was own and opperated by a moron, who was using the completely rusted oved top of his powermatic table saw which he described as the jewel of his workshop as a place to paint horribly cobbled together bird houses with house paint from the dollar store which should have been thrown out when it got lumpy a few years ago.
 
Last edited:
It sounds as if you want to do some large work, let's say over 24". Look at the designs of those lathes and dig deeper. If you are considering using it often, other effects, in addition to bearings and their designs, also come into play. The physical size of the spindle, and you could get away with some less expensive designs by using a solid shaft. You don't need a morse taper insert. As long as you are able to make sure the faceplate won't unscrew. I would recommend at least 1.25" and 1.5" threading would be better. You want as many bearings as possible, and close to the head end. And make sure the shaft is hardened so it is less likely to bend.
 
Some lathe information

I own an Oliver 20C lathe- weighs in at 4,500lbs 12' bed and when I turn large objects there is absolutely no movement whatsoever because of the precision of the machine itself and the shear weight-all cast iron- it is absolutely massive and weighs more than my car or van! I have to tell you that you are flirting with disaster trying to make it structurally sound using BB wood- even with all of that bracing-inertia and out of balance material will definatly cause some problems- maybe not in the beginning, but over time it will be very dangerous. My suggestion to you , and you will be so much happier, is to get an old lathe that is designed to handle and manipulate wood and you will absolutely not want to leave it alone!
I have seen large older lathe beds, American, Rochester and even Oliver’s at 10' lengths/w headstock-tailstock -without motor for anywhere from $500- $2000. There was a 20' large metal lathe with everything (in VGC) going for $350.00!! On Ebay and no one bought it. It was going to the scrap yard if it wasn’t sold- what a shame!
It was really not all that difficult to move the lathe from where I bought it and it was well worth every penny I spent. As any craftsman will tell you†you’re work is only as good as the tools that you useÀÂ
 
been on vaction

I have not given up on creating a lathe of my own design, it is the only way I am sure I will ever get the lathe I truly want with all the features I want in one package but for now screw it because it isn't important. I am still working on the design project but with far less enthusiasm as I am sick of know it all engineering students who have never worked at anything outside of fast food.

I returned from vacation after having spent more than a month turning in the impresive studio of Jack Flimsin in central oregon. I feel humble returning to the lathe that griz delivered while I was gone a little 16" swing model in need of a variable speed motor. I will get to it some time between now and going to England I am sure. However after having turned in Jacks studio and tried every one of the lathes he has so whimsicly bought since winning the lottery, I have found the lathes I need but won't be getting for a while.

For all all my desire to have one machine that turns everything I could want to turn without designing and building my own that just isn't going to happen. I do think I will be very happy with a ray peck bowl lathe. Until you split a nearly 4' diamter log of big leaf maple, mount it to a 16" face plate and chain hoist into place it is hard to imagine just how big it really is. And when you realize the sacrifice area of the blank is lager than the biggest bowl most turners will ever turn it truly is staggering.

I used to think that the be all of turning lathes for would be a heavily accesorized 2436 or a vb36 and I would spend around $9k by the time I had all the options I wanted on it. That was before I turned on a laguna pinnacle. When turned side by side with the vb36 (complete with tailstock) and a outboard moded OneWay they no longer hold much inerest for me. Being able to remove the bridge from the lathe and turn a 45" platter using the tailstock was incredible. It was a beautiful of a turning machine as either the vb36 or oneway and at a few grand less to get the same thing has definately sold me. If there were anything I could change about it that would be very simple. I would have an extension for the bridge. After chucking up a large piece I am restricted in depth of the piece, while designed mostly for tabletop work with a bridge extension of 8 or 12" I see a lot of projects for myself with huge pieces of crotch wood. The second function I would change would simply be an option at the time of building a standard 48 hole index like the oneway with the option of going to 96. With the aweson router and spiral attachments for this lathe this would be a definate boon.
 
Lathe...

I don't know if there is a US dealer for these, but take a look at the WivaMac DB1200V...

DB1200V

It's a fantastic machine, will take 21" over the bed, the head will swivel to give a potential of floor depth, and has 48" between centres. After a long time looking at the VB and others I chose this one.

Just a thought

Andy
 
TurningDog said:
I checked out the Griz lathe for sale and not only didn't it run it was beat all to hell. I am afraid it to see what the guy would call poor condition because good condition had noticeable bend in the spindle. However I after looking the Griz lathe over it seems pretty feasible to me to add custome fit cast iron riser blocks and have new bolts made for the cam locks. This also seems like the most financially feasible big lathe option for me as well. I can get a 16" lathe from them delivered for less than $500, I have the dc vs motor and outboard tool stand already and can't see 2 simple casts for riser blocks costing very much. But my question is how tall do you think I could make them and keep the head and tail stocks stable? My thoughts are, atleast on the headstock riser, is I should add some extra length and add a second or third position to lock it down the bed.
Click to expand...

http://www.turnwood.net/Photopost/showphoto.php/photo/2709/sort/1/cat/last14/page/3

Shows a picture of a modified HF lathe that now swings 16. He still has the tool post assembly to modify.

John 🙂
 
TurningDog said:
I have not given up on creating a lathe of my own design, it is the only way I am sure I will ever get the lathe I truly want with all the features I want in one package but for now screw it because it isn't important. I am still working on the design project but with far less enthusiasm as I am sick of know it all engineering students .........
Click to expand...
Don't give up on your dream -- just make it a longer range goal. Learning how to design and build one to suit your needs will also have a side benefit of enhancing your education as you develop the necessary expertise to successfully complete the project. Don't blame the engineering students -- they probably have much more enthusiasm than free time and their repertoire does not yet include real-world solutions. One final thought is that you shouldn't do this project expecting to save money -- as with any design and development project, there will be changes made along the way that will result in scrapping some hardware and replacing it with new stuff. In fact, it may turn into a perpetual project as changes are made from time to time.

Bill
 
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