Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Garyv on April 29, 2008, 03:08:46 PM

Title: Joining_linear-rails?
Post by: Garyv on April 29, 2008, 03:08:46 PM
Title: Re: Joining_linear-rails?
Post by: MachBruce on April 29, 2008, 06:37:45 PM
Hi Gary,
Anything is possible. the trick might be to make sure you have identical linear rails (!) and accurately machine a surface to mount them on. The best method is to have the rail mounts machined in position on the machine bed.  This can be easily done be an engineering company with a large mill.  Can be expensive but it is worth it.  Because the mounting rails will then be accurate and true, anything you mount on the rails should also be spot on. ( or as near as you can hope for. ) The key to accuracy is rigidity - make the frame solid and everything else follows. Having an accurate face and edge for the rail to mount against should enable you to add rails end to end.

Title: Re: Joining_linear-rails?
Post by: zarzul on April 30, 2008, 11:51:07 AM
Like Bruce said it can be done.  Since each truck has a dozen+ balls in contact with the race at once, only one ball will feel the joint at a time.    I joined several in my router table build and it is pretty much bumpless,  I can hear a tic as I push it over the joint but I can't feel it.  At first I carefully milled the end of the first two that I joined and then bolted them down butted together but then the next two I just joined them without milling, I can't tell any difference since only one ball is at the joint at a time anyway.

I am still building and have not tested it on material yet,  just running the steppers back and forth, still working on electronics & wiring.


Title: Re: Joining_linear-rails?
Post by: Garyv on May 01, 2008, 08:28:53 AM
Title: Re: Joining_linear-rails?
Post by: blackbeard52 on October 07, 2008, 04:53:07 AM
I have extended rails in the past with no effect on accuracy. But just as mentioned the alignment is the key. mill or grind the ends to match as close as possible.