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How to make the collimation thread?

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#1 cnchillstar

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Posted 22 November 2020 - 08:59 AM

I plan to make a mirror cell like this, is the collimation bolt thread in the horizontal bar? The bar is hollow tube I think, is it enough thick to for thread?

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#2 Couder

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Posted 22 November 2020 - 10:06 AM

you can buy the square pipe (also called square tubing) in various thicknesses. Of course the thicker the wall, the heavier. You can buy thread inserts and various things to hold the collimation bolts in thinwall pipe.


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#3 DLuders

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Posted 22 November 2020 - 10:55 AM

Yes, McMaster-Carr has some threaded inserts that can work for you.



#4 Sean Cunneen

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Posted 22 November 2020 - 11:10 AM

You can tap threads through most square tubing, I have done so with a couple of builds with no issues. What I haven't had luck with is having threaded bolts feed through holes drilled in square tubes, the threads of the bolts don't allow for smooth turning, they get hung up and caught up on the tubing hole rims...



#5 wrnchhead

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Posted 22 November 2020 - 11:18 AM

In the automotive world for putting threads in sheet metal with no way of getting to the other side we use rivnuts. 

https://www.rivetnut...vnut-rivet-nut/


Edited by wrnchhead, 22 November 2020 - 11:18 AM.

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#6 dave brock

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Posted 23 November 2020 - 01:01 AM

The trick is making sure the tap is long enough so it taps both sides of the tube from the one direction. It needs

to still be engaged with the first side when tapping the second side.




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