shaft welding

[caveman]

hi every one' just sort off fishing for ideas im building a hybrid 16v mini and have to weld two different drive shafts from different cars together have looked into this abit and some of the main probs are twisting and snaping.they way other people seem to do them is machine sort of a step out shaft then weld then sleve then weld.will prob end up doing it like this but just wondered if any body on here knew of a better way

 

[penfold]

That's about the only option other than having a shaft custom made from scratch(assuming you don't have a machineshop at home capable...). Provided the spigot and socket are a good fit alignment shouldn't be a problem, and the sleeve on the outside should result in a shaft practically as strong as the original. The only problem I can foresee would be the material the shafts are made of; probably a heat treatable alloy steel like EN24 or similar, which may require special rods/wire and/or pre/post heating. Other forum members with more knowledge may like to elaborate?

 

[George641]

Ive welded shafts together before without a problem, big V n keep welding. Could sleeve it too. Hardest bit is to get it reasonably straight, was only on a banger for me so didnt have to worry about nockin the cv joint or inner out as we dnt get many miles LOL

 

[ta borom]

Well, Well...I've done that on the MAIN shaft of my land rover...nissan mated to L?rover transfer box...so you could imagine the amount of torque it has to witstand...the method of sleeving was used but failed 3 times over a period of 3 years(and only doing mild offroad)...what i did last time was to taper the shafts and sleeve to be press fitted into the sleeve...then weld it on the outer side.
Considering the mini being a front wheel drive...so you get a lot of slip from the tyres...I would go for the latter method...it's been used by drag racers on the grip juice...so should be ok for street use...
Whichever method you use....the problem of welding steel is that it gets brittle near the weld and that's where it is likely to snap

 

[Drains]

You should be able to vee it and mig it, but restrain both ends of the shaft so they cant move, use a weld sequence to keep it straight, and let it cool between sets of sequenced welds. You don't want the whole thing getting red hot as it will seriously weaken the steel - it'll be brittle as, and won't take the loads.

I'd start by joining the job together at the points of the vee, then build up a bit welding round the joint. Once theres a bit of meat on there and the axle is straight (knock it into line if it's not), start welding in line with the axle at say, 12 o'clock, 6 o'clock, 3 o' clock and 9 o'clock. Next runs at 1,7,4 and 10, etc. Your first runs might only be half an inch long, but they'll get longer as you work out of the vee. Just watch the job doesn't get too hot. Let it cool slowly before you continue if it's going to overheat.

 

[caveman]

thanks guy,s some good advice there love this site now im stumped ive looked into having some shafts made out of en24 and billet cheapest was about £250 well out of my budget so think im gonna get a couple of sets and practice and test se witch ones do the job

 

[Chris_]

Weld it, sleeve it. Then drill all the way though it (sideways) and stick a dowel through with a quick tack to stop it dropping out. Do this both sides of the joint.

With the sleeve, even if the joint fails you should only lose drive and not have a shaft flailing around underneith.

Chris

 

[BillJ]

Have you seen this thread, posted recently?

http://www.mig-welding.co.uk/forum/showthread.php?t=15113

 

[Bsmith]

You should be able to vee it and mig it, but restrain both ends of the shaft so they cant move, use a weld sequence to keep it straight, and let it cool between sets of sequenced welds. You don't want the whole thing getting red hot as it will seriously weaken the steel - it'll be brittle as, and won't take the loads.

I'd start by joining the job together at the points of the vee, then build up a bit welding round the joint. Once theres a bit of meat on there and the axle is straight (knock it into line if it's not), start welding in line with the axle at say, 12 o'clock, 6 o'clock, 3 o' clock and 9 o'clock. Next runs at 1,7,4 and 10, etc. Your first runs might only be half an inch long, but they'll get longer as you work out of the vee. Just watch the job doesn't get too hot. Let it cool slowly before you continue if it's going to overheat.

Great advice Drains but why grind the pieces to a point which would look like a centre punch tip?
I have always welded round bar, bolts, etc with a flat bottom vee more like a chisel face. Leave a gap between the pieces, weld one side, turn over, grind to first weld, weld second side, turn over, weld etc. Remember to check alignment after each weld and knock straight. When the 2 vees are full of weld I do a cap right round. Think for a drive shaft I would use higher tensile welding rods like E7016 or E309L.
Good luck, Brian (",).

 

[Drains]

Great advice Drains but why grind the pieces to a point which would look like a centre punch tip?
.

I didn't mean to imply that - you're quite right, that would be silly. Point"less" in fact . Also a pain to weld. I meant a radial vee with a flat tip. In fact a better prep - depending on the size of the stub might be a j-prep, which could save time and weld metal.

However, I reckon your solution is better for sure, and keeps it easier to keep the shaft in line. On bigger stock, i'd go with a full radial prep though. Not sure why...

 

[penfold]

Just in case we're talking at cross purposes; this is a sketch of what I thought the OP meant, and also what I meant as well. Once this is welded up a sleeve can be added for proper belt and braces. For maximum strength it would be best to preheat and allow to cool very slowly.