[Hobbiest]

Use small pieces of metal, wood- or whatever, that will be rigid enough for the application- in between the linear guides and the frame. Doing it in this way, you can make the top surface of an egg carton straight and square. I disagree though that it is impossible to build out of welded steel with any precision. It won't be perfect, will need some shimming, but I bet I could build one with the same precision as with MDF. Course it is comething that I do everyday (welding), and I do realize that other people practice other things all day long. Maybe I will try it with some of the scrap we have at work.

[balsaman]

I said the frame would not be precise, but it' doesn't matter. I did not say the machine will not be precise. The machine can be built precise on an in-precise frame no problem as long as you are aware that things will need to be shimmed.

Eric

[Hobbiest]

Didn't mean to bicker Eric...sorry. I do think that the frame could be make fairly precise though. Still think I might give it a try. Anyway, back to the subject of the thread...you should be able to make your machine extremely precise by using shims to locate your rails.

[balsaman]

I didn't take it as bickering.

Eric

[kanankeban]

Ok... Now I know I can make the frame with steel...Now I need to know if implementing rack and pinion is the best way to drive the x,y,z? if so, What are the appropiate rack, gears and all the stuff needed?
And the big question? how do the rack and pinion work? , I mean what is the science involved there, I've seen that they use reduction gears and wird stuff...
Regards...
Hector

[turmite]

Hector I have used a machine with rack and pinion since 1991. The only problem I have ever had out of that machine is dust in the rack, and electronic related. There are ways to use the rack that will eliminate the dust problem and would recommend that approach. Do a search for rack and pinion drive systems and you will be amazed at the number of sites you will have to look at. Precision Drive is one but I think McMaster Carr, J&L, MSC and others also carry the systems.

Eric you mentioned the shimming of the ways and I was curious if you or anyone had ever considered bedding the ways? hey do it on some of the big machines using some sort of epoxy/metal matrix that is really hard and durable.

One other ot question. How in the world can you make changes to you text body while posting without it deleting more than you put in? Look above to the "hey " at the beginning of the last sentence.????

Mike

[balsaman]

After you post you can click the edit button to edit the post...Is that what you mean? Also make sure you hit the "insert" key on your keyboard if it's over writing text as you try to edit existing text in your post...

Bedding the ways can be done too I suppose. I have not tried it.

Eric

[ger21]

I've seen what Mike's talking about once or twice before. If you try to add a word or sentence in the middle of what you already typed, It just types over what's there, instead of just bumping it forward which is what normally happens in any app I've ever seen. I think it must be some bug reply window.

Like Eric said, Mike, if you see that problem, just submit the reply asis and then edit it.