How do I fix 4"x1/4" flat to 3"x3"x1/8 box without welding?

[Apples]

Hi all,

I need to mount a length of 4" flat to the side of length of 3" box. The flat needs to go in the centre line of the box. This will give me some overhang on either side of the box. Then I can mount my bishop wisecarver track to the edges of the flat.

I really don't think that I could weld the flat to the box becasue it will make the edges of the flat all out and not srtaight anymore.

I was thinking of useing some roofing type screws with the self drilling cutting end on them. I will make a hole in the metal so that the screw will not have to cut so much metal.


What's the go, what should I do?

P.s please don't say tap it. I have like, 150 holes to tap then.

Peter
Australia

[ViperTX]

If you size the hole correctly some thread forming screws might work...you'll have to experiment. The metal roofing screws are designed to thin guage metal and will probably snap in 1/8 inch thick steel. Nuts and bolts will also work. I probably would shy away from rivets and threaded inserts.

[Geof]

Peter;

"P.s please don't say tap it. I have like, 150 holes to tap then."

Wimp! (Couldn't find the smile)

But seriously, I have welded nuts to a long strip of 1" x 1/8" (Oops 25mm x 3mm) flat bar to make anchor nuts and then run this down inside the 3" x 3".
When drilling clamp the flat bar for the anchor nuts between the other two pieces.

This is actually more work than tapping the holes with an electric drill but if high grade nuts are used it is much stronger than the threads in the thin wall of the tube.

[mxtras]

The self drilling screws should go through and hold in 1/8" (3.18mm) material. How well depends on the screw size - I have used as small as #10 with reasonable success.

What about the thread forming screws used on automobiles - never looked into buying them, but maybe that type of fastener is available?

Scott

[One of Many]

Hi all,

I need to mount a length of 4" flat to the side of length of 3" box. The flat needs to go in the centre line of the box. This will give me some overhang on either side of the box. Then I can mount my bishop wisecarver track to the edges of the flat.

I really don't think that I could weld the flat to the box becasue it will make the edges of the flat all out and not srtaight anymore.

I was thinking of useing some roofing type screws with the self drilling cutting end on them. I will make a hole in the metal so that the screw will not have to cut so much metal.


What's the go, what should I do?

P.s please don't say tap it. I have like, 150 holes to tap then.

Peter
Australia

If you have access to the inside of the box. I wonder if rosette welds from the inside would be easier? All you would need to do is drill holes in the box side and weld thru the hole?

No adjustment and not removable though.

DC

[Apples]

One of many,

I had thought of maybe welding like that, but I am still worried about the possible bending that might happen if weld. Which will put the gantry axis out then.

Geof,

Theat is a good idea witht the flat strip on the inside of the box.

ViperTX,

What is a thread forming screw???




Peter

[ViperTX]

Thread forming displaces metal to form the thread....works great in aluminum.

[andy_ck87028]

Thought of using slow cure high strength epoxy?

Drill along the length (every 12 inches perhaps?) using oversize holes for positioning and place spring washer under bolt head.
Pre-heat metal to around 40dec C with a hair dryer, clean surfaces with acetone and glue together.
Position and clamp down the glued surfaces with the bolts and come back in 15 mins and clamp down further.

I have been told this is then strong enough not to warrant roll pins but I tend to over engineer and so will also use roll pins.

By the way, I am about to do this myself when my son can get me the glue. I am confident the advice I received is good.

Andy