Spot Welder Arms and Electrode Tips

[martin seymour]

Just bought myself a crypton triangle spot welder, it came with the original arms that are bent at an angle at the ends and uses the tapered tips - these look quite beat up. Fitted though are what looks like some DIY made arms that appear to be some straight 1" diameter copper bars drilled at the ends at right angles to take some 6mm(?) electrodes - these are held in with Allen screws gripping directly on the electrode.
Now I'd like to modify the arms to take a better method of holding the electrodes. I see that there are caps that could be used or using cotter pins to hold in the electrode. Would anybody be able to supply me with a drawing of their preferred method so I can make some - and what type of copper to use? Cheers

 

[500e]

Welcome to the best site on the net.
But why re invent the wheel

 

[voipio]

Spot welders need the connections between the various conducting bits to have the lowest resistance possible. The grub screw method of holding the tips is possibly the weakest link in the setup in the image.

 

[500e]

The tips fit the arms and the screw is to lock it in place, so you have the contact aria of the tip in the hole to carry the current.
It is an old machine so some wear is expected, tips should be a good fit

 

[martin seymour]

Welcome to the best site on the net.
But why re invent the wheel

But I already have two wheels! I have the tapered type tips that looked shagged and the ones attached with an allen screw which is a crap way of doing things!

 

[500e]

.Other way's

I have seen them tapered and beaten into the hole as custom made ends at a push

 

[500e]

 

[stuvy]

.Other way's
View attachment 375975I have seen them tapered and beaten into the hole as custom made ends at a pushView attachment 375974

Thats how mine are locked in place

I tried copper rod and it deforms really quickly

 

[daedalusminos]

The cotter pin is OK, but ultimately it pushes the electrode to close the clearance in the hole....as does the grub screw. The cotter pin requires two intersecting holes at 90°, you can select either hole for cotter/electrode....down side is you need a cotter approx £5 or make your own

 

[Robotstar5]

I tried copper rod and it deforms really quickly

I'm sure the type we used at work were a copper/berylium alloy, seemed a lot harder than plain copper.

 

[daedalusminos]

You want copper chromium zirconium alloy

 

[martin seymour]

The cotter pin is OK, but ultimately it pushes the electrode to close the clearance in the hole....as does the grub screw. The cotter pin requires two intersecting holes at 90°, you can select either hole for cotter/electrode....down side is you need a cotter approx £5 or make your own

I imagine then the cotter pin doesn't mess up the electrode - a drawing of the cotter pin would be nice