Truing up an axle

[adamfitz]

Evening all. Bit of a stab in the dark here but hoping you guys can help
Been building a drift trike over the last few months, the axle is made up of a length of steel bar turned to 27mm to slide through 2 bearing carriers. Have a sprocket and brake disc carrier welded to it.
Had a friend turn it down and cut the key way as I had no access to a lathe at the time. Fitted it all up and went for the first test ride today and it appears the axle doesn't run true, giving a feeling the wheels are oval!
Easy option is to start again with the axle but it's more time and money.
Any suggestions? Current thought is to turn it from the bearing to the end down to say 20mm and then make up a new sleeve to sit inside the bearing, hoping it will then run true

 

[Wallace]

Is it out of true on the welded section? Without a photo, my first thought is to straighten it between vee blocks then true up the disc/sprocket mount.

As an apprentice I would chat to the guys truing up half shaft forgings after heat treatment, a skilled operator could get them within 0.005” in seconds. They were worthwhile keeping in with if you rode a motorcycle and had a lack of talent and kept running into things.

 

[adamfitz]

Is it out of true on the welded section? Without a photo, my first thought is to straighten it between vee blocks then true up the disc/sprocket mount.

As an apprentice I would chat to the guys truing up half shaft forgings after heat treatment, a skilled operator could get them within 0.005” in seconds. They were worthwhile keeping in with if you rode a motorcycle and had a lack of talent and kept running into things.

I tried to upload a video but it wouldn't work for some reason. Going to speak to the machinists at work today to see if they have any ideas and see if i can borrow a DTI to find out where it is running out

 

[atomant48]

Possible easier to start with an axle off a kart and use the ready made disc and sprocket carriers etc ? Is the axle bent or is it just not rigid?

 

[addjunkie]

Or are the bearing carriers not true, is the drive chain too tight causing bend in the axle.

What grade of steel is the axle?

 

[adamfitz]

the axle is mild steel round bar. 27mm in diameter. Id have thought it is rigid enough and not bent. it may have occurred when part of it was turned down in the lathe to match the bearing carriers, one end turned down, flipped round and then the other turned down.

 

[addjunkie]

If you take the axle apart and roll it on a kitchen bench top or similar, you will be anle to see the bend, assuming you havent welded bits on to it.

If you have you could put it between centers in a lathe and use a clock gauge to locate the bend.

 

[adamfitz]

thing is its got a sprocket welded to it. willy try and get a photo uploaded later today. may have the chance tomorrow to get it between centres in a lathe and see whats what

 

[Screwdriver]

Ideally you want it mounted on roller stands. Have a search on YouTube for Keith Fenner and sub search flame straightening.

 

[adamfitz]

Hopefully that shows things better

 

[addjunkie]

Could be your welds to the sproket have caused the distortion.

 

[Windy Miller]

What dia is that thing on the end of the shaft, and what's the shaft length? If it's less than 9" dia and less than 18" long bring it down next week when you pick up the bandsaw and we can clock it up in my lathe.

 

[adamfitz]

The hub on the end comes off-only held on a pinch bolt and keyway. but the shaft must be about 800mm in length. I will have to measure it

 

[anto44]

Most go cart axles I've seen haven't been welded on because of distortion. Hubs and sprocket holders are normally bolted or on a keyway. If you try any bearing supplier they should be able to get you lenghts of shaft steel (not sure what the proper name for it is), it can be got plain round or with a keyway in it. I don't know what grade it is but it's definitely much tougher than mild steel.

 

[adamfitz]

Most go cart axles I've seen haven't been welded on because of distortion. Hubs and sprocket holders are normally bolted or on a keyway. If you try any bearing supplier they should be able to get you lenghts of shaft steel (not sure what the proper name for it is), it can be got plain round or with a keyway in it. I don't know what grade it is but it's definitely much tougher than mild steel.

yeah thats usually the case bud, i went with a length of bar rather than a pre made axle because it suited the application. I must admit i didnt expect it to distort anywhere near as much as it has with just welding the sprocket to it. Theres an engineering firm next to where i work so might stick my head in there next week and see what they can do

 

[Windy Miller]

The hub on the end comes off-only held on a pinch bolt and keyway. but the shaft must be about 800mm in length. I will have to measure it

Bummer

 

[addjunkie]

If your makeing a new axle, use something like EN16T or higher, and machine a mount for the sproket and use a key way or something, dont weld it, unless you are very careful to avoid the distortion.

 

[weldingnovice]

Don't have any advice on how to straighten your axle other it probably not cheap as straightening fork stanchions uneconomic unless rare.

Have a look on here for info an cart axle builds.

https://www.facebook.com/pg/Trikeracingcom-229572580536662/photos/?ref=page_internal

Drift also known as flat track or missile trikes, site was hosted and had some detailed builds.

I went for this



Not a cheap option though