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Building up a shaft

Posted: Sat Apr 11, 2020 6:46 pm
by simon.holyfield
Folks,

Another little job to amuse myself during lockdown. This is a little Honda kickstart shaft which had lost all its splines and was very mangled at one end. I've machined it true and cleaned off some lumps of weld, and the plan is to build it up with TIG and recut the splines.

Has anyone done this before? I need to put about 2mm on the radius and 5 mm on the length before I can machine it to the finished dimensions.

IMG_20200411_181210.jpg

Re: Building up a shaft

Posted: Sat Apr 11, 2020 10:24 pm
by Paul_Linden
I’m interested to see how this can be done.
When I found myself in the same situation I took the easy route and welded a new splined section on the end (which is still there).

Re: Building up a shaft

Posted: Sat Apr 11, 2020 10:34 pm
by simon.holyfield
Paul_Linden wrote:I’m interested to see how this can be done.
When I found myself in the same situation I took the easy route and welded a new splined section on the end (which is still there).


That could be an option. I'm wondering how I am going to lay down a continuous 'cylinder' of weld over the shaft. I expect that I will lay it down, machine it, discover holes, try and fill them & struggle with inclusions...

This post shows how I am planning to cut the splines:

https://ariel-square-four.blogspot.com/ ... e.html?m=0

Re: Building up a shaft

Posted: Sun Apr 12, 2020 12:53 am
by john.whiting
Welding on a continuous 'jacket' is simple ,and is done all the time ,even on crankshafts....However ,Ive fixed lots of these jap splines on kickstarts by the simple expedient of drilling a hole lengthways /1/2 in the k/s lever ,1/2 in the shaft ....and including the split in the lever ,then drive in a roll pin,clamp up the pinch bolt...........Incidentally ,all these devices that clamp a split boss onto a fine (rolled) spline are self destructive .....because as soon as the spline connection loosens slightly ,the splines start to strip as the lever is clamped .......A very good example is the Ross Hydrapower steering box on the big Ford Louisvilles ,its the Ross HF 64 I think ....all the splines on the pitman arm disappear ,and the lever is loose on a truck rated at 90 ton GCW.

Re: Building up a shaft

Posted: Sun Apr 12, 2020 3:37 pm
by rick king
Aren't cranks usually done with a submerged arc thing.

Last thing sort of like that I got asked to do was a magneto armature, it looked like
desperate dan took a bite out of the threaded end, I rebuilt it and cut new threads.
It went how you wrote, weld it up and remachine.
For the armature I used 312 stainless rods.
How is the shaft held in the quadrant?

Re: Building up a shaft

Posted: Sun Apr 12, 2020 5:24 pm
by Mick D
Hi

I think I'd machine the shaft out of the quadrant and make a new one from silver steel.

Regards Mick

Re: Building up a shaft

Posted: Sun Apr 12, 2020 5:26 pm
by simon.holyfield
rick king wrote:How is the shaft held in the quadrant?


There’s a continuous fillet on the side you can’t see. You thinking I could turn a new shaft? Not a bad idea, I hadn’t thought of that - or the idea of using an axial pin.

Re: Building up a shaft

Posted: Mon Apr 13, 2020 1:05 am
by john.whiting
No disrespect,but kids need to be taught the proper way to use a kickstart too....mesh the gears first ,then apply pressure.....every time I go to a vintage run ,I see lots of younger riders smashing away at kickstarts ....and even some joking about getting gears jammed and jumping on the pedal........personally ,I doubt a classic bike will survive the present generation of owners smashing gearboxes ,over revving motors ,and riding at crazy speeds .......and finally ,we have the "I must modify the motor more so I can keep up with the Jap bikes"...And dont ask about why a Jap bike can be allowed on a vintage/ girder fork only run.....OK Rant over.

Re: Building up a shaft

Posted: Mon Apr 13, 2020 3:20 am
by nevhunter
ALL good points John. IF you are 18 can you still play in the under 13's? OLD bikes are special interest not a necessity,. If it's dead easy to revive a Jap thingy with good brakes and suspension so YOU can put in little effort or discomfort, eventually everyone does it so where is your girder fork run then? Seen it happen so may times..Nev

Re: Building up a shaft

Posted: Mon Apr 13, 2020 6:07 am
by simon.holyfield
I was very impressed on a trip out with my son the other day, who has had my W/NG for a couple of months, as he wanted some vintage bike experience. He was trying to start it, and I watched him put it in gear and rock it before kicking it again. No angry boots on the jammed kickstart!

Later he admonished me for failing to fix the kickstart bushes...

But you're right. It will be interesting to see how his 5 year old, who is considerably less patient than his Dad, learns to ride this little QR50 I'm putting together.