Making steel ways?

[ZipSnipe]

If any of you guys were going to make steel ways for a milling machine lets say out of steel 14" x 2 "x 1/2", what size mill would you use? Or would you even use a mill to make the ways? Or what would you use?

[Geof]

Originally Posted by ZipSnipe If any of you guys were going to make steel ways for a milling machine lets say out of steel 14" x 2 "x 1/2", what size mill would you use? Or would you even use a mill to make the ways? Or what would you use?

Last question; "Or what would you use?"

If this question is asking what machine would I use other than a milling machine to turn lengths of steel into the ways for another machine the answer is; a largish Shaper or a smallish Planer.

If the question what would I use for the ways I was making one answer is; not steel.

Middle question; "Or would you even use a mill to make the ways?"

Yes, because I would not have any idea where to find a Shaper or Planer.

Answer to first question; "A machine with enough travel."

And I am pulling you around a little bit (pulling not jerking ) but my second answer "not steel" to your last question is serious.

If you are planning on machining some dovetail ways or box ways using steel flat bar for a a DIY mill my suggestion is don't. You will have a devil of a time keeping things perfectly straight. It will be impossible using cold rolled and difficult using hot rolled. Even if you are able to get them acceptably straight you cannot slide a steel way against a steel way; they will gall together no matter what lubricant your use. For sliding surfaces, whether they are linear ways or a simple sleeve bearing, the general rule of thumb is to have different materials; one softer than the other such as a steel shaft and a brass bushing. I only know three exceptions to this rule: 1) Brass sliding on brass is okay; and I put brass only and do not include bronze because some of the exotic high strength bronzes will gall when run together. 2) Cast iron sliding on cast iron is okay, obviously because that is what is most commonly used. 3) Hardened anything against hardened anything; chilled ground cast iron, hardened and ground alloy steel, hard chromed and ground.

For making DIY dovetail or box ways I think the best choice is ductile cast iron bar. It is a charm to machine, does not warp after machining and slides nicely against itself with a bit of lubrication. I have made a few machines with sliding ways using ductile iron. The next choice is hot rolled steel on brass; I have done this once using 1/8" brass strips fastened to the steel ways to avoid the expense of big solid pieces of brass; drilling, tapping, countersinking dozens of holes was tedious. Hardened and ground anything is not practical for DIY I think.

[ZipSnipe]

Thanx Geof, you just saved me a headache of learning expierence, I had it in my head that i could use steel, and I kept forgetting that most ways are cast Iron. So if I wanted to make dovetail ways for my machine a mill with travel longer than 14" is required? You think the Seig X3 would cut it? I was planning on getting a bigger mill that runs $500 bucks more but I keep saying to myself well if the X3 can cut it then the extra $500 bucks can go towards the various tooling I,ll need.

[Geof]

Generally yes you need longer travel than your workpiece. Actually quite a bit longer is best if you want to machine something straight over a good distance; most small mill tables droop a bit at each end of their travel so this inaccuracy gets permanently incorporated into your workpiece. It is possible to do a job much longer than the travel; I have machined 60" workpieces straight to =/-0.001" on a machine with 42" travel by relocating the part and aligning it with a dial gauge. Very tedious but this was in a Govt research center so time was not an issue .

I cannot advise you on the Seig becasue I am not familiar with it. I tried to find some via Google and what I did uncover was the model ZAY7045L from Lathemaster; this looks like a good home machine. The price is certainly healthy from a hobby shop point of view but my advice in this area is get the biggest and best machine that you are fairly confident will do the job now and into the future even if this means spending your tooling budget now and raiding your kid's piggy bank on a dark and stormy night . You can always sit down and admire the machine until you have saved enough money for tooling and when you have done that and start using the machine you will be happy. But if you by a minimal machine now you are almost certain to be unhappy in the future and if you start raiding piggy banks to buy a second and bigger machine you are going to be in big trouble.

[ZipSnipe]

Yeah I agree the Zay45 looks like a sweet machine. I,m kinda torn between it and the X3. The Zay45 no doubt can handle anything that I throw at it. The only downside is the price,weight and girth of the machine. The X3 could probably handle most that I throw at it( I do wonder about this iron ways that I want to make, only this first one will be 14" long the rest will be 12" and smaller)
the plus to the X3 is size, price and it looks like it would not be to difficult to move the machine from one place to another if needed. I actually see in the near future that these machines will be moved 2 to 3 times. Thanx for your input Geof

[Geof]

Take a Charles Atlas course

[Zumba]

Zip,

Ways are cheap. That's why you find them on cheap machines. A factory in China can pour a cast iron base with integrated dovetail ways for less than what it costs us to buy a single THK rail in the states!

But we don't have large foundries, and we're not in China! If we're going to spend the effort toward making the machines ourselves, we might as well use quality components/designs, rather than copy the cheapie design. I'm not sure if you've ever played around with a cross-slide table with the lead screw removed. If you have, you probably noticed that the table was extremely difficult to slide back and forth. That's how much friction there is!

Besides, if you plan on using a Sieg X3 type machine to make another machine from raw materials, the new machine cannot possibly be more accurate than the Sieg. In all likelihood, it will be slightly worse, unless you have access to a surface grinder or have skill in the lost art of way scraping.

All quality commercial VMCs these days use THK style guide blocks. The most reasonably priced clones of THK are made by Hiwin, sold at www.automation4less.com. The rail runs roughly $45 per foot at 25mm wide. Blocks are $60 without a scraper, $90 with. As you go up in size (increments of 5mm rail width), add about $5 for the rail, and $10-15 for the blocks.

Pretty pricey, but it's so easy to get a perfect sliding surface. The base can be a horribly cast, rough piece of crap. Just drill/tap the holes accurately, add some shims, and you have accuracy measured in ten thousandths. The friction is gone as well. You can push a 200 lb cast iron table with one or two fingers.

Not to mention that homemade ways are WORTHLESS to the general public, whereas used linear guide blocks can be sold on ebay for close to what you paid for them. I rarely buy stuff expecting to sell it, but I make sure that if I have to, I can. Kinda like putting money in a house. You hope you never have to sell it, but you feel good anyway when the value goes up.

[wizard]

Geof makes fairly good points but I think he missed one opportunity if box ways are acceptable. That would be prehardened tool steel that can be purchase from a number of places. This is usually ground fairly accurately to size and could be used for hand built machines where you don't have the ability to harden and grind. You still need a flat support structure underneath.

Going this route still leaves you with the issue of what runs against it. Even hardened steels of the same type can have issues. Ideally you would run castiron or a synthetic material against such a way. Brass would also work. Synthetics shuld also work on unhardened tool steel rather well and you still get the advantage of sized and ground sections. The big disadvantage is the sections aren't cheap be they hardened or not.

It is something to consider and should allow you to build a fairly nice axis with very modest resources. It doesn't give you dovetails but they are at times a bit over rated, if the time is spent to proeprly fit up box ways.

This is the only suggestion I can give you beyond casting and maching the ways as needed. You could always go the THK or similar route but that is big bucks but real ways are much nicer if you don't need the axis speed. Also if you can cast the iron in therory you could do the ways without any machine tools. Not that I'd suggest that but it is an alternative.

Thanks
Dave

Originally Posted by ZipSnipe Thanx Geof, you just saved me a headache of learning expierence, I had it in my head that i could use steel, and I kept forgetting that most ways are cast Iron. So if I wanted to make dovetail ways for my machine a mill with travel longer than 14" is required? You think the Seig X3 would cut it? I was planning on getting a bigger mill that runs $500 bucks more but I keep saying to myself well if the X3 can cut it then the extra $500 bucks can go towards the various tooling I,ll need.

[dertsap]

i agree with wizard about the steals , if you use lets say a tool steel dovetail and a cast iron dovetail , the harder steel will use the softer as a lubricated surface (self lubricating) cast iron is great in such an application , look at the old house screw jacks , they used the same principal

[ZipSnipe]

Thanx for the info guys. Even through I,m making a manual mill I still plan on purchasing a mill to help make the manual mill and then what ever else I can conjure up. I know the Chinese make it cheap and they can,t be beat or so they say. I just wanna see if I can build a manual mill. And then I want to later convert it to cnc. I,m at the point now where I need the z axis ways( I missed an oppurtunity to get a single axis Gilman slide that would have been perfect, however a new Gilman slide is almost the cost of a Zay45) So anyway I,m planning on getting most likely an X3(even through my spending demon will kick my little saving angel's ass and probably get the Zay45) and I was thinking that if I can,t find something that is reasonably priced that I,ll just try to make it on a mill and gain some experience at milling.

[NC Cams]

Re: prior post about "tool steel".

IF you mention tool steel as the spec, it is just about as accurate to say that the stuff has to rust, sink and be magnetic. Unless you know how to heat treat it and can find someone who can do so without ruining it, I'd think twice about calling a steel supplier and asking to buy a non spec'd grade of "tool steel".

Tool steels have their purpose.

M2 is for one thing and L6 another and O6 something else. Rub M2 against M2 and it will gall - period. Rub M2 against 06 and it will either slide or cut the O6 - it all depends on heat treat and finish and hardness of each. O1 against M42 will do something entirely different.

If you don't plan to lap and grind your ways, you'r probaby better off buying roller type, preloaded linear guides as they can be "bolted together" - all you have to do is figure out how to bolt them down and align them straight.

NSK is a source but they are not cheap. We scored some surplus ones that, new, would have cost nearly as much as a used mill.

Speaking of which, for the cost of some import machines, you can buy a decent one and rework it easier and perhaps cheaper than machining your own.

Or, find a decent used mill and refurb it. THe import stuff can be decent (work in progress) or crap. Decent stuff can be turned into a gems with TLC and some hand working. Crap is crap. A used Bridgeport can usually be sold for what you paid for it whereas a new import will depreciated a ton before you even get it home.

For optimum sliding friction (as in low) you want one material that is sliding to be harder than the other. This is why GOOD gib style machines (Excello and/or Bridgeport mills) had precision machined IRON tables and ways that had one of the sliding members hard chromed, scraped and lapped.

BTW, there was a thread on this M/B how to scrape and lap, it is a good one to find if you plan to do it....

Bronze ways simply aren't going to be rigid enough or as wear resistant as chromed, scraped and lapped iron.

Hope this helps....

[ZipSnipe]

I,m sorry NCams, I really did mean to say iron ways, I just kept forgeting that ways were made from cast iron..