McWire Cartesian Bot v1.2 screw sizes problem.

Hi all. I've downloaded the dxf files for the xy and z stages. I imported them into solidworks because I want to get a feel about how everything is put together as I make a list of the things I need to get. I have seem to run into a discrepancy with the fastener sizes however. Can someone help me resolve this?

I have been following the BOM on the mcwire build site and I notice that there are only three sizes of screws that the build uses.

Self Tapping Screw 10-24 x 3/4" - diameter of 0.1900"
M5 x 15 cap - diameter of 5mm = 0.196"
5/16" x 3/4" machine screw -diameter of .3125"

When I look at the hole diameters when I import the .dxf file as a new part, I get the following.

hole_dimensions:
0.313"
0.157"
0.134"

The .313 matches the 5/16" holes, but the other hole diameters don't match! The other hole sizes are too small for the M5 and 10-24 screws. Should I ignore the BOM and instead just find correct matches for these hole sizes?

Thanks in advance.

bump, anyone?

Ok..

If you want to use imperial nuts and bolts the nearest imperial size to 5mm is 1/4"

The self tapping screws you could just drill the holes out with a 1/8" drill.

I'm sure the original instructable was from USA... and fully imperial measurements.

Enjoy...

http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Machine/

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The holes are sized to be tapped. Once you tap them the screw will fit perfectly. If you want the screws to instead go through and secure with a nut, you will need to drill them out to the size of the screw.

Edited 1 time(s). Last edit at 01/02/2010 01:53PM by NewPerfection.

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