Google is probably your friend here.

Did a quick search with building up splines with weld as the text and got a number of useful hits from reliable sites

Only one I looked at was a thread on the MIG Welding Forum titled Spline Repair. Nice thing about MIG Welding Forum is that its UK based and (usually) doesn't call out anything uber hard to get over here.

Start Quote from one reply

You don’t want to use anything too exotic like SuperMissileWeld which is basically just a jumped up nickel rod.

Either 309/312 if you think the original shaft is a hardenable material.
Or just go right ahead and weld it with ER70s2 TIG or 7018 stick

End quote

Clive

Edited By Clive Foster on 08/05/2022 19:48:51

Driveshaft for a 10 ton truck? Or agitator drive for a washing machine? Could make a difference with rod choice.

Col21, since there are a lot of splines, I guess they are vee or involute, probably the latter as these can be hobbed like gears.

So, if you plan to machine one, you might check for curved teeth.

Bill

Its a bit big for a model, smaller splines than that are used on helicopters to transmit thousands of horsepower.

It's a good observation on the relationship between OD, teeth and module, but that does not necessarily mean it can be called a gear nor can we infer that a gear cutter will form the tooth spaces correctly.

Splines have different geometry to gears, specifically the relationship between pitch diameter, addendum and dedendum. In particular, spline teeth are considerably shallower than gear teeth. In a way, they are roughly analogous to a stub tooth gear profile (I think Fellows had one, designated, for example, as 6/8). As for pressure angle used on splines, we would have to do further research.

There is a set of softwate called MITCalc, which offers a spline module for 14 Euros. Even if a person did not want to buy that, the documentation for that module tells you what you have to measure to identify the spline.

Splines are not the same as gear teeth, necessarily. There are various standards for splines, separate from gears, including ISO, DIN, SAE and BS. Among those there are then straight-sided splines, serrated splines and involute splines. Then among the latter can be any of a number of pressure angle involutes ranging from 14.5 degrees to 45 degrees.

Some clue as to what this gearbox is out of would be helpful. 10 ton truck? Or washing machine? Made in which country? Made when?

Another way you can do it is weld it up and make a fly cutter to match one of the undamaged splines and use that to recut the same profile on the welded bit. Rods to use depends, once again, on what the application is. How many horsepower will it be transmitting? At how many rpm? For how long and how often?

Cutting the internal splines could be done in a slotter or shaper, depending on the length of the spline required.

He’s a bit cute re info – location or finer details.

I might guess – but only a guess – is it is on the JCB he was enquiring about, earlier.

I might guess that it is something on the axle drive – to accommodate articulation or track adjustment maybe?

JCB diggers can come in a wide range of sizes/power.

Come on Col21 tell us what it is used for or what vehicle it belongs to, if you want help please tell us the full story.

Oh well six days have gone by and Col21 doesn’t seem to want to share with us. I am concerned that unless we get the full story regarding his post we can leave ourselves open to trouble if things go wrong. Where exactly do we stand legally by recommending a material or process. A bloke on the forum said it would be ok etc. Maybe I am overthinking things, maybe when this heat goes away I will be back in workshop and working rather than thinking.