First time build - Steel Frame CNC Router

**examorph** · 28-02-2016

Steel box section and plate had arrived earlier on in the week:
Attachment 17758 Attachment 17757
Ended up buying a tungsten carbide blade for £80 to cut this as 5 of the 6 local suppliers I visited advised that the machine had a "non-standard" 25.4mm shaft.
Seemed to work fine the first day but when trying to cut the box section the next day, it seemed to require a lot more time/force, I think I may be cutting too fast and wearing out the blade.
Attachment 17759
Ended up with a bit extra 100x50 section and too little 50x50 section, I underestimated how much box section it would require and assumed I had more than enough at 7.5m of each. Guess its true what they say about assuming!! Requested price for 1m more of each and changed the design slightly to use the larger box section for the horizontal bracing:
Attachment 17760
Other than the two sections I am ordering, all box section has been cut, but unsure if some of it is still good as I think maybe 3 sections (bed supports and gantry box section) are 3-5mm shorter than what I needed, will this be OK filling up with weld?
Attachment 17761
Was hoping to have it all welded up this week but ended up being a slow start with the few hick ups pushing things back a week

All in all, it was a good experience and even though I had some problems, I enjoyed it and learnt a lot of new things

Some questions I hope you guys could help me with please:

From what I understand 5754 aluminium is the grade but if specified as tooling plate, would this be OK for use on the Z-Axis without having to face it off?
As this machine will be moved 3 times (welded in workshop, epoxy leveled in a smaller room for heating and installed in a shed) is it worth welding some adjustable feet to the legs?

**Davek0974** · 29-02-2016

Hi
I don't think you will be able to bridge 5mm with weld, if you had say five joints you could maybe bridge 1mm on each, better to make the frame fit what you have now, or maybe weld in a 5mm spacer plate somewhere. Done properly this could work.

Yes machined aluminium tooling plate is very good and ideal to use as-is.
Yes, fit heavy adjustable feet, always useful, but not the weedy ones with M8 threads ;)

**njhussey** · 29-02-2016

Originally Posted by examorph

Other than the two sections I am ordering, all box section has been cut, but unsure if some of it is still good as I think maybe 3 sections (bed supports and gantry box section) are 3-5mm shorter than what I needed, will this be OK filling up with weld?

You'll be putting a tremendous amount of heat into the steel if you try to fill it. Why don't you do as Dave says and put a spacer, or cut a bit more off and weld a plate onto each end?

Some questions I hope you guys could help me with please:

From what I understand 5754 aluminium is the grade but if specified as tooling plate, would this be OK for use on the Z-Axis without having to face it off?

Yes tooling plate is the thing to go for, needs no surfacing.
As this machine will be moved 3 times (welded in workshop, epoxy leveled in a smaller room for heating and installed in a shed) is it worth welding some adjustable feet to the legs?

**examorph** · 29-02-2016

Thanks guys, will get some adjustable feet sorted (>=M12) and also cut out some 50x50x10mm steel plate to weld to the frame legs for this. Will also make adjustments where I can to reduce the 5mm gap on the steel box section.

njhussey - Thanks for spotting that. The clearance behind the plate is 10mm, think I could get away with using hex heads and tightening them up with a spanner?
Attachment 17769 Attachment 17768

**examorph** · 02-03-2016

Been a nightmare finding a local supplier that does box section without a 7.5mtr minimum order charge, but got one eventually who can do me some off cuts at a 3mm wall for a good deal.

Will the 3mm wall thickness box section be OK for the bed support beams and horizontal supports shown below in green? Will it also be OK to weld?
Attachment 17786

**Clive S** · 03-03-2016

Originally Posted by examorph

Been a nightmare finding a local supplier that does box section without a 7.5mtr minimum order charge, but got one eventually who can do me some off cuts at a 3mm wall for a good deal.

Will the 3mm wall thickness box section be OK for the bed support beams and horizontal supports shown below in green? Will it also be OK to weld?
Attachment 17786

The main problem apart from resonance with 3mm box is that it is not quite thick enough to tap 4mm or 5mm would be a better option. If it is just for the green bits then it is probably OK

**Boyan Silyavski** · 03-03-2016

3mm is ok, if size is 80x80 or 100x100. I wouldn't use it for smaller than that.

No problem with tapping and screwing 3mm, just have to be careful and drill holes using a guide so they are true 90degree square to profile.