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-   -   X Rails Centres Distance (http://www.mechmate.com/forums/showthread.php?t=4647)

Duds Tue 30 September 2014 05:13

X Rails Centres Distance
 
I'm using 3mm steel angle and mounting v-rail on the outside referenced to the bottom of the steel. Mainly to use up steel I had in stock, I also had some 8mm stock that I wanted to use, but unfortunately no 6mm.

Can I get a sanity check on X Rail Centres?

The drawings show that the Gauge Rod is Y+461mm

What is the X axis Rail Centres Value? For Example: Y+n (Where n is the value to the centre of the v-rail.)

I have come up with Y+(n=464mm).

Drexel Wed 01 October 2014 05:06

Just a newby thinking outloud so take this with a grain of salt (MechMate not even finished yet).
If you mount your pre-ground rail on the outside of your steel will you still be able to reach your rack with your motors?
I used alum., placing my pre-ground rails on the inside and the gears on the motor shaft just reached my rack. I ended up having to countersink the screws holding the hardened rail on my alum rail and replace all of the button head screws with flat head screws to get it close enough to reach my rack. Not sure this applies to what your doing, just didn't want you to find out to late this might be a problem.

smreish Wed 01 October 2014 07:04

John,
I have personally built both versions with VeeRail and MM DIY manufactured rail with the grinding fixture.

The overhung details with the VEErail is a very important note to pay attention to.
I found that with OM 7.2 geared motors, 30T pinion from Browning and 1/2" - 20 Rack I was able to just (without compromise) make the engagement of shaft-to-pinion with the hub fully seated on the motor shaft AND 90% pinion engagement to the rack. Gerald carefully looked at this section drawing with the alignments while I was the guinea pig for this evolution of the Mamba drawings. In the finished version that is in the package, you will find the rail on the INSIDE of the angle and sitting on the interior of the angle iron. Some folks in MM land have used STEEL angle and cut down and put the vee rail on the now cut and finished surface. The difference in center line alignment is negligible if the wall thickness of your angle section is 3/16 +/-. The thicker the angle section, the greater the deviation.

You can see a detail drawing here of the progress during design:

http://www.mechmate.com/forums/showt...5&postcount=26

Please NOTE this is NOT the finished drawing which is CORRECT in the drawing package in which the VeeRail sits on the interior of the aluminum angle and the cut edge of the angle does NOT necessarily support the rail, but merely a bolt surface.


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