Thank you, Yves.

Bonzo · Thursday at 12:35 PM

Our youngest lad, Michael is a pretty gifted engineer and so I asked him if he fancied a challenge!

Nearly a decade ago, Yves posted the following thread for his fix for the Alton ES / woodruff key issue...

Thread 'Alton starter my solution for broken woodruff key (2017)'

Nov 25, 2017

Broken woodruff key is a problem with alton starters because the sprag weel is only sandwiched and the power come on the key, and the key is not made to hold the power and will brake after a while.
The solution is to make a connection between sprag weel and the triplex sproket.
Here is wat I did:
1: make two flats on the sprag weel

2: Make a new spacer with two inserts that go over the two flats from the sprag weel
The right piece is the original Alton spacer, the left one is the new one,
don't look at the two big holes, I will explain this later

3...

I printed off Yves' diagram and showed Michael a few photo's and gave him a few Alton parts and off he went.

First off, following Yves' dimms, he made the flats on the Alton sprag, and then made a milled out spacer followed by a couple of 5/16" sharpened grub screws, for me to assemble onto the crankshaft with the woodruff keys, and 'mark' prior to drilling.

Today, he sent me a text saying "ready for collection".

Bonzo · Thursday at 12:37 PM

Thank you to Yves for dreaming this all up, and a special thanks to Bonzo Jnr.

Proud Dad

MichaelB · Thursday at 3:33 PM

Nice Work!!

olympus · Friday at 7:19 AM

For those who don't have the skill set or necessary machinery to carry out this modification, we need an enterprising person to manufacture these modification kit for forum members with Alton starters
Anyone interested???

Dedubyah · Friday at 2:25 PM

I would definitely be interested. Alton must have sold a ton of starters so I would say there would be a ready market if a run were CNCed

nortonmargie · Friday at 3:23 PM

Calling Son of Bonzo! Would you be interested in taking this on?

zotz · Saturday at 6:11 AM

You would think, this being a fairly common issue and a relatively straight forward fix that Alton would incorporate it themselves. Just sayin'

MexicoMike · Saturday at 7:09 AM

Seems odd that Alton wouldn't have addressed this if it was a general problem. They quickly revised the alternator rotor back in '13 after several of the 1st version disintegrated in service and there have been no rotor issues since then.

Bonzo · Sunday at 5:02 AM

nortonmargie said:
Calling Son of Bonzo! Would you be interested in taking this on?

He's a great kid (he's 34, but still our baby

), loves helping people and would do anything for anybody.

He works in aerospace engineering and does these one-off jobs for me when he gets a few minutes here & there, only trouble is he's flat out most of the time and also doesn't like to take the piss at work. They don't mind him using their machinery to do the odd project, but running out a batch of them might not go down well.

If he wins the lottery he says he'll retire, get himself a workshop & gear and do things like this for a hobby.

I'll let you know if he chooses the right numbers

baz · Sunday at 5:43 AM

zotz said:
You would think, this being a fairly common issue and a relatively straight forward fix that Alton would incorporate it themselves. Just sayin'

The thing we don't know is how common it is
IE how many units have been sold with no issues?
How many weren't fully tightened by the fitter ?

Bonzo · Sunday at 6:40 AM

baz said:
The thing we don't know is how common it is
IE how many units have been sold with no issues?
How many weren't fully tightened by the fitter ?

I haven't had any issue's with mine (apart from toasting the 3 original inserts that it came with - I've now put six of the newer version inserts in as per the recent update from Alton), but got the spacer made as a precaution.

baz · Sunday at 6:55 AM

Bonzo said:
I haven't had any issue's with mine (apart from toasting the 3 original inserts that it came with - I've now put six of the newer version inserts in as per the recent update from Alton), but got the spacer made as a precaution.

Did you keep the Woodruff key as well as the two driving pins?

olympus · Sunday at 7:46 AM

Bonzo said:
He's a great kid (he's 34, but still our baby ), loves helping people and would do anything for anybody.

He works in aerospace engineering and does these one-off jobs for me when he gets a few minutes here & there, only trouble is he's flat out most of the time and also doesn't like to take the piss at work. They don't mind him using their machinery to do the odd project, but running out a batch of them might not go down well.

If he wins the lottery he says he'll retire, get himself a workshop & gear and do things like this for a hobby.

I'll let you know if he chooses the right numbers

Totally understand Bonzo, but surely there must be a small Engineering firm out there who could re manufacture these..... if full auto heads can be produced surely these can??

MichaelD · Sunday at 8:38 AM

olympus said:
Totally understand Bonzo, but surely there must be a small Engineering firm out there who could re manufacture these..... if full auto heads can be produced surely these can??

Looks like FullAuto heads can't be produced any more, the company making them has lost interest and won't be making any more

Bonzo · Sunday at 8:58 AM

baz said:
Did you keep the Woodruff key as well as the two driving pins?

I kept the engine sprocket key and the driving pins, but not the rotor key.

Bonzo · Sunday at 9:07 AM

olympus said:
Totally understand Bonzo, but surely there must be a small Engineering firm out there who could re manufacture these..... if full auto heads can be produced surely these can??

Yeah, totally agree.

Michael had no problem making it from Yves' diagram. I gave him the spacer back to drill where the pins needed to be* and then I got him to turn a bit of a chamfer on the engine side of the spacer as it was catching in the dish of the sprocket.

* I don't know if drilling the holes for the locating pins may be an issue for a mass production as I'm not sure you could guarantee every one would line up with the woodruff key?

Bonzo · Sunday at 9:09 AM

MichaelD said:
Looks like FullAuto heads can't be produced any more, the company making them has lost interest and won't be making any more

Wish I had a spare £2.5K

baz · Sunday at 10:29 AM

Bonzo said:
I kept the engine sprocket key and the driving pins, but not the rotor key.

When I bought the kit from Yves I had to modify it to fit the different offset that my belt drive front pulley had
I also added the alternator woodruff key although yves said it was unnecessary and I tend to agree
But as I'm a belt and braces type bloke I couldn't help myself

concours · Sunday at 10:38 AM

olympus said:
Totally understand Bonzo, but surely there must be a small Engineering firm out there who could re manufacture these..... if full auto heads can be produced surely these can??

They absolutely could be produced.
It will not be cheap.
Programming
Tooling
Setup time
Material
Run time
Profit
Are you willing to pay up?
$500 each?
$200 each?
It certainly won't be $50.

olympus · 2026-03-30T02:31:59-0600

concours said:
They absolutely could be produced.
It will not be cheap.
Programming
Tooling
Setup time
Material
Run time
Profit
Are you willing to pay up?
$500 each?
$200 each?
It certainly won't be $50.

Until an accurate costing process is carried out & an evaluation on tbe potential take up from the forum members .... we won't know the actual cost?????

Thank you, Yves.

Bonzo

Thread 'Alton starter my solution for broken woodruff key (2017)'

Bonzo

MichaelB

"Sons of Arthritus"

olympus

Dedubyah

nortonmargie

zotz

MexicoMike

Bonzo

baz

Bonzo

baz

olympus

MichaelD

Bonzo

Bonzo

Bonzo

baz

concours

olympus

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