Macro Rail

dolmadis · Post by **dolmadis** » Sat Mar 23, 2013 5:57 am

Thanks Soldevilla.

John

rjlittlefield · Post by **rjlittlefield** » Sat Mar 23, 2013 10:38 am

soldevilla wrote:I'm not sure I did it right, but I have left in my dropbox a sketch of the wooden rail. Although it is a little big, it's so cheap that maybe some friends can consider building two units and cross them to get a precision XY stage.

The image in dropbox works fine for me.

I think it's worth mentioning that if you're careful, you don't even need the drawer slides. Here is a photograph of the alignment method used by the South Bend Lathe Company for their precision machining tools. It consists of two smooth triangular rails on which the carriage simply slides. Gravity pushes the carriage against both surfaces of the rails so there is no play in any direction.

For DIY purposes, you might prefer a single triangular rail to maintain alignment, and a second flat rail just to support the other side of the carriage. This would avoid any concern about having to make the two rails precisely parallel.

Of course this simple mechanism only works in a horizontal configuration. But in that case, it works very well indeed.

--Rik

ofarcis · Post by **ofarcis** » Sat Mar 23, 2013 11:55 am

I think is dificult to construct because need special machines and calibrate the result. I think is better to adquire rail lines like this:

Why complicate your life when there are already manufactured lanes that are not overly expensive.

This can use in vertical and horizontal solutions. The precision is very high.

See my solution for my last focus rail:

In the right have an stepper motor recycle like this:

Of course, It's my opinion.
Regards, Oscar.

rjlittlefield · Post by **rjlittlefield** » Sat Mar 23, 2013 1:02 pm

ofarcis wrote:I think is dificult to construct because need special machines and calibrate the result.

Are you talking about my illustration of carriage sitting on triangular rail?

--Rik

ofarcis · Post by **ofarcis** » Sat Mar 23, 2013 1:25 pm

Yes, to do triangular rails good calibrated is not easy.

Regards, Oscar.

rjlittlefield · Post by **rjlittlefield** » Sat Mar 23, 2013 2:26 pm

Yes, to do triangular rails good calibrated is not easy.

Perhaps you misunderstood my intention.

If someone is making a DIY specimen stage, then the rails just need to keep the stage aligned and moving in a straight line.

Triangular rails can be easily made by slicing the corner off a rectangular piece of wood using a table saw. Glue them to another couple of blocks of wood, and you have a sliding stage that will move in a straight line very well. No calibration of these components is required.

Certainly such wooden rails do not have the precision of South Bend's carefully milled and lapped cast iron lathe bed, or a modern crossed-roller linear bearing, or perhaps even a Delrin bushing on a polished stainless steel shaft. (I'm not sure about that last one.)

But as an inexpensive homemade solution suitable for horizontal use on a table, a triangular wood rail can be surprisingly simple and effective. The best approach depends on the goals, tools, and skills of the person doing the project.

I think we have gotten quite far away from crayfish74's original question, which asked "Anyone could recomend to me a Macro Rail on Ebay or other web?". I believe he was asking for recommendations about a rail that could just be purchased, not assembled. But hopefully the later discussion is of some use to other readers.

--Rik

ofarcis · Post by **ofarcis** » Sat Mar 23, 2013 2:32 pm

I think sure all it's useful to readers, any types of solutions exposed.

I've made all my focus rails so I can not help to buy one on ebay, sorry. My only experience on Ebay for these things was buying a bellows to China and was very bad.

Regards, Oscar.

soldevilla · Post by **soldevilla** » Mon Mar 25, 2013 11:27 am

This is an easier solution to the hilt: a wooden door stop, with some marks and a bit of red paint...

and two images taken by a friend with the wood rail

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Solutions are very easy to get a horizontal rail, I have recovered from my garage my foucault apparatus of the old days when I was building telescope mirrors.
All we need is a metal tube, two pieces of L profile brass with an inverted V cut and a spring. The micrometer has lost a steel ball glued to its end that pushing on a piece of glass. The black knob ends in a screw with rounded tip which rests on another piece of glass. This simple system allows precision displacements as high as 0,005 mm.

Yes, It have a lot of dirt...