welding steel base or just getting aluminium extrusion

[Nr1madman]

Also think about if you are gonna use drills as they can be longer than routerbits.
I got the tip to calculate z travel/clearance based on thickest material and longest drill I plan on using :)

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[reefy86]

most of the 3d work will be on mdf

[Neale]

Any chance you can use layering in your CAM setup to cut the piece in layers with registration pins for cutting and reassembly? I know it depends on what you are making, but just in case this is for something like MDF moulds, it might do the job.

[reefy86]

It was a thought but joining those pieces together and making it look seamless on some pieces maybe tricky.

[reefy86]

how much room play do you leave when drilling and tapping? for example i am using 20mm linear rails on the z axis and the screw clearance is 6mm so i would need to use smaller bolts then 6mm to make room for alignment.

[Nr1madman]

how much room play do you leave when drilling and tapping? for example i am using 20mm linear rails on the z axis and the screw clearance is 6mm so i would need to use smaller bolts then 6mm to make room for alignment.

I made a huge error when drilling/tapping my first plate. Went with m6 as the holes were 6mm and chinese drawing said m6 holes.
Turns out that m6 boltheads couldnt fit the countersink in the rails :D
So use m5 bolts, 4.2mm drill..
That gives you 1mm adjustment.
Done correctly thats plenty ;)

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[reefy86]

Thanks i had m5 in mind but wanted to double check :)

[Neale]

I used M5 as well - works fine and although you don't have a lot of adjustment range, there should be enough if you are careful. I made up a steel drill guide (a short length of steel bar with a 4.3mm hole through the middle) that had a reduced diameter one end that fitted the counterbores in the rail so it centred the drill accurately. You can then use a similar guide with a 5.1mm hole to guide the tap so that it goes in square.

[driftspin]

M5 too here.

The first of a set of 20mm hiwin X axis rails takes a lot of time to line up to what ever straight reference.
I checked 100 times before drilling the first holes.


After squaring up the gantry to the first rail, the second rail (X) wend a lot faster using the gantry as a guide for the second rail relative distance.



I clamped down using 3 clamps before pre drilling 3 holes over 1830 mm span, ends and middle, with a 5.9mm drill, to remove epoxy and centre drilling a centre hole for 4.2 mm drill.


I have a well balanced, old :-) battery drill.
Its easy to keep vertical 90 degrees to the surface and used no other tools.

I used the 6mm hole from the rail for a guide icm with the 5.9 epoxy removal / pre centre drill and drilled 4.2 and tapped all m5 free hand with the battery drill.


Bought 2 machine taps m5 and 5 4.2 drills from toolstation (volkel) did about 100 holes in 4mm steel with 1 drill 4.2mm (ground hss) and 1 tap and still going strong.


Just use oil on drill and tap, and vacuum clean all holes before tapping.


I have had no problems with off centre holes or problems tapping the treads.


After tapping there is some wiggle room but not a lot about 0.5mm ...


After torqueing down the m5 i have had no binding trouble in the carriages.


Hope this helps.

Grtz Bert




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[reefy86]

Thanks guys, just would like to ask a question that i can't seem to find the answer to on the forum But has anyone ran a machine for multiple years using epoxy resin without it weakening over time? also what methods do you do to get top and bottom rails lined up to exact same position?



Got my keys today for my workshop so will be cracking on soon :)