[abeblinkin]

I'm going to turn down a brake stay out of aluminum to weld to a 39mm fork bottom to fit an early sportster/fx drum brake (the ones that came on the 33.4mm front ends). I was looking to get some 6061 to do this, will that be except able as far as strength and weldability to the alloy in the lowers? I was thinking it would be ok as the direction of force pushes the stay into the back of the leg. Any other tips on doing this would be appreciated I'm fairly decent with the tig on metal but a novice when it comes to alloys like, which tungsten or filler to use to practice. I have some 5356 rod would that work? Thanks

 

[dhallilama]

i've got 39mm forks w/early drum... 6061 for the brake stay. welded to the lower.

NOT TIG specific, but....
i oxy/acetylene welded it (lots of experience with oxy/fuel welding aluminum... it's an outright pain in the ass, need to use f'ed up flux, i don't recommend it but my tig was broken at the time).
i've got super narrow trees as well, the same lower needed to be cut to form around the drum; it's filled with 6061. i *THINK* i used 5183 for the filler, but i gotta double check.
5356 is on the chart i use for aluminum for joining t6 to 5005, 5052, 5086, t6... i'd reckon it'd work.

edit: pic-tar fo prettyness...

 

[abeblinkin]

Thanks for the info, you did a good job on that. Did you switch out the bearings or turn down the 39mm axle to fit. I was thinking since the bearings in my hub are new and I have the 39mm axle it would be easier and cheaper just to make the axle fit rather than change the bearings. Did you have any problems with the fork lower warping or anything when you put all that heat to it?

 

[dhallilama]

i had an axle for a wide glide that i shortened, turned down & threaded. it's all i had handy, but it was quick/easy.

i didn't have any warping problems.... but i did f up the inner diameter of the fork lower in one small area, where i partially melted through. to fix it, i spent some careful time with some files, cursing myself for not paying attention to the heat.

 

[Jeff L]

That's what I used too.6061

 

[abeblinkin]

Thanks for the replies I'll watch that inner surface and make sure I don't go too far through but I guess I'd rather curse myself for getting too much penetration than too little as long as the lowers stay straight. I looked at your build thread and you obviously did much more extensive modifications than what I have planned so I think I should be alright. On the stock 33.4mm front ends the stay is miged in two spots that are very short, though it is steel I think I'll be ok with welding the alloy all the way around...thx

 

[selectedgrub]

Extensive welding it would be wise to clamp down and leave to fully cooled.

 

[MeanMike]

Ask your welding supplier about 4043. We use it all the time on the railroad welding T6061 to cast Al. It lays a nice bead. I've used 5053 also, it's a little stronger, but they recommend heat treatment aftwards.
Dhallilamma, nice skills. I hate oxy welding. I worked in a street rod shop with a well known old timer. He would say tig was for school girls. This cat could lay some of the prettiest nickels you ever seen with a torch.

 

[Jack Adams]

I'm with mike,when you are not 100% sure what the alloy you are welding 6061 to,4043 is your safest bet. Jack