rectangular tube 1/16th wall...tap or thru

[slp_prlzys]

Hi,

I'm wondering if any1 could tell me if
it would be strong enough for a tube with
1/16 wall to be tapped. It will be holding
a thk rail with a dozen CBored hole.
I got me a table, with 1" melamine( I plan on adding 3/4 MDF on top of it),
but the frame is 1-3/4 and 1/16 wall, it seems perfect, for my application.
I just need to put a lot of braces .

Should I just use longer bolt then nuts,
the rail is not tapped, but needs M4 to get thru.

I've started my build with a footprint of 30"x30".
it will be used as an plexiglass cutter/engraver,
but will try to push it harder maybe cut 1/8 thick aluminum.(just maybe).

thanks.

[Ken_Shea]

M4 is small, what THK size is that?. With a M4 and even a fine .5 pitch would account for only about 3 threads, not enough at all. If you have access to the inside you could insert say a 6mm backup strip and then tap that.

Ken

[diarmaid]

1/16 wall what....aluminium...steel...?

[ViperTX]

either use an insert or a long bolt with a nut.

[slp_prlzys]

the rails 15mm HSR model I think, unfortunately there's no
access to the inside of the tube, The frame is made of steel
and it's probably softer than usual.
I have the frame drilled and tapped, I'm trying to rig up a
power supply for my el-cheapo usb camera so I could show you
what it looks like ,but could'nt find the darn driver for it.

what I'm thinking, maybe I should just drill all the way to the other side
of the tube and use a longer bolt with 4mm or 5mm DIA ( what's the closest
equivalent of this in inches?) I guess this is my only option, or trash it altogether
and start from scratch which would make my build time longer.

[widgitmaster]

Even with a long screw, the tube will colapse!
You didn't say if you were a welder, but if you drill a 3/8 hole through both walls, and weld a solid pin from both ends and grind smooth, then you can drill and tap all you need! This would give 100% more strength and regidity, which will help in the long run!

Hope this helps!
Eric

[diarmaid]

25mm = 1 inch.....therefore.....3mm = approx 1/8 inch....5mm = slightly less than 2/8 inch

[slp_prlzys]

Here's a couple of pic I got just before I blew up a 7805 regulator.
I have it temporarily attached 4 screws holding each rails.
the X axis is surprisingly stiff. I think I'll sandwich the frame with 1/8"
flat bar, maybe it would work, I'm not sure what screw size I need
(preferably imperial) that has the right head size and has nut.


diarmaid:
thanks for the calculation, I'm hoping there's a imperial standard
screw that's almost the same size as M4, with head that would fit
on the CBOREd rail holes.

widgitmaster:
'am no welder but a friend who knows how to will be helping me
with the braces.

thanks.

[Ken_Shea]

8-32 or 8-36 will fit.

[slp_prlzys]

I have another question while I'm at it ( so I dont' have to start another thread)

the aluminum on my x axis is 4.5" high is it wide enough to split
the two rails, I mean it would only be 3.5" apart if I put the two rails in it.
the plate for my Z axis is 6"x10.875", I'm hoping to have atleast 2-3" of travel for it.

thanks.

[DareBee]

Installing NutSerts in the tubing should work well for your application

[slp_prlzys]

is this the kind of nutsert?
seems like a good idea.

I'll try the 8-32. with the nutsert 'wonder if it's available locally.

thanks.