If it looks like a bed...

[sammorgan3]

If it looks like a bed, and weighs like a bed, then it might just be a bed! Alright, here's my point, I just picked up what might be the bed for either a new lathe or mill build. Its a diesel engine cylinder head, from a 90's model international truck. Measurements are 35" long, 9 7/8" wide, and 5" tall, some rust, nothing a file or sandblasting wont take care of. Weight on bare head casting is 250 - 300 pounds!! Top, bottom, and both long sides are ground to what i can only assume are accurate. My plan is to box in the casting with 1/4" steel bottom, ends, and two long sides. Head will be inverted, with the combustion chambers facing up, as this should be the most accurately ground surface. After boxing i will likely fill all of the cavities with epoxy granite, then top off with two 3/4" x 3" steel bars to bed my linear slides onto. These bars will be scraped as flat as possible for mounting. Tell me what you guys think!

P.S. The rear axles on these large trucks are about 2" diameter with a large hub integral to the shaft. Could make for a nice lathe spindle, the hub being cut down to create a chuck flange. These should be nice steel, just a thought. Pick the junkyard!

[svenakela]

The head idea was very nice, I may copy that in the future!
One very good thing with old heads, they have absolutely no tensions left. As you said - with some EG in it would be a great bed.

[S_J_H]

It is a very good idea IMO.
Wish I had thought of it. Nice big hunk of seasoned iron, can take to any machine shop for a quick surfacing with no hassles.
Just do your best to make it not fugly and your set.

Only problem with an axle for a spindle is no through hole. But if that is not an issue and you'll only be doing short chucking work then it will work fine and is probably some pretty tough alloy.

Steve

[sammorgan3]

Glad I'm not the only one that thinks this is nice seasoned iron! All those heating and cooling cycles in the engine, then it's sat outside and weathered for about 6 months without being touched since my dad pulled it from the truck... should have already moved all it's going to

As for fugly, that's what the steel plate surrounding it is for, as well as to hold in the EG.

I had the idea at work tonight to attempt a box ways mill, it seems that some large cnc mills use all box ways. Not sure if this is because of the cost of linear slides in these sizes or not, but i figure it would be little trouble to upgrade the mill to linear slides if it already has accurate box ways. So I'm gunna go for it!

Worst case scenario i can see with box ways is too much friction or sticky action. Anyone with experience using box ways care to comment? Also, would it be beneficial to use brass/bronze wear pads on the slides to cut out most wear on the ways themselves? Only thing i could see wrong with this option is frequent/large adjustments of gibs, and possibly lapping action on the ways caused by hard particles embedding themselves into the soft wear pads. Also, i know linear slides are faster, with less friction, and just as accurate as a good hand-scraped box way if installed right, but there's the cost issue. Most importantly I could be much more proud of my work if i have an accurate, repeatable machine riding on surfaces i finished by hand! BRAGGING RIGHTS GOOD! (Guess I'm the only 22 year old in the world ready to go through hundreds of hours of tedious work just to say "I made that what it is")

Sorry if I repeated questions or anything, just got off work, with no sleep last night... bed's calling me pretty loudly...

[S_J_H]

Box ways are one of, if not the strongest type of way system.
I have read a few articles about modern machines comparing them with roller linear slides. A big advantage for box ways is greatly increased damping.

Box ways if built right will have very low friction. Take a look at my thread about the horizontal line boring mill I am building. It uses a 36" long box way Gilman slide for the bed. The carriage on this slide while not as fast and stiction free as the linear slides on my cnc lathe is extremely free to move and unbelievably smooth. Now to make something like that from scratch would be a lot of work with a the necessary hand scraping involved, but it is possible IMO.
Steve

[The Blight]

All machines that I know of that have box ways, have some kind of coating on the ways to reduce friction.

[sammorgan3]

Hm... seems like box ways are the way to go then. (pun not intended) Give me a chance to see if I'm really any good at scraping anyway. (probably not! ) The friction free coatings are a difficult hurdle, don't think I can get my hands on anything tough enough. But the hydrodynamic properties of any plain bearing should come into effect. It should ride on the very thin layer of oil. I may use brass or bronze wear pads on the carriages. These brass wear pads, if I give them oil slots should reduce wear on the ways themselves by being softer. But full way covers will be in order to keep small hard particles out of the slide, unless I want my brass wear pads to become lapping pads!

Hm, a mill with 18 - 20" x travel, 12" y and 14 - 16" z, ambitious isn't it? I should have access to two machine shops though, one at my old high school and one at my old college. Maybe It is doable, especially with hand scraped box ways... Just must have patience with scraping!

Oh well, I'm off to work, I may have a few other ideas when i get back

[The Blight]

You could check out moglice or turcite for a friction free coating. I think turcite is kind of a sheet that you apply with some adhesives and then scrape it. It gives you a low-friction surface, but it's not plane, so it needs scraping or machining. Moglice is a liquid which you can apply to a surface while it's mated with the ways. When it has hardened it gives you a low-friction surface. You will have to use a release agent on the ways when applying the moglice. There is a topic on here where it was used on a X2 milling machine.

[sammorgan3]

The turcite sounds pretty interesting, read up on it slightly. Only one problem. Seems i cant buy it! every place i find wants me to email them for a quote. Just doesn't seem like the way business should be done, y'know? If you go through the trouble of setting up a website with all of the info on your product, and you're happy to ship it and accept credit card payments, then why not have a shopping cart on your site?

Oh well, back on topic. So I'm looking at boxed in cylinder head with EG fill, hand scraped box ways, and turcite lining. (if possible) Too bad I have to finish the shop before I can start another project, but at least ill have a nice idea lined up.

What is the accepted formula for homemade EG?

Thanks for the help guys!

Morgan: out

[Eson]

This is very interesting! You're not the only the only 22 year old in the world ready to go through hundreds of hours of tedious work just to say "I made that what it is". I am too.

I have also thought about box ways. My idea is to use train rails as a base and then grind it square. You can probably get a couple of 'small' (by their standards) pieces of rail from a train yard. Also i would recommend Moglice, it seems much more easier to precision cast then to scrape.