37 replies to this topic

[Ethel]

They do look like they could've made in the bronze age & it could be a nice side-line for somebody with surplus melt from bigger castings.

[gaspen]

 

 

 

 

 

 

 

I've thought about this on and off many times. I'd make a fixture for sure, it would just make the job so much easier and repeatable. While they could be machined in a lathe, I'd most likely do them using the Fixture in the Rotary Table on the Mill. I'd say the factory most likely had a cutter that would have done both faces of the fork in a single operation, though, to maintain precision and finish, I'd only at one side at a time.

 

 

 

Sure, I'm just trying to brainstorm (fart) a least cost 'n most amateurish way to do it. Agree, the best solution  would be for some kindly expert machinist to gather up all the dead ones and do a batch of 'em 

 

If you were try a replaceable face approach, might it be easier to fab up some sort of carrier, a bit like a brake caliper & pad arrangement?

The forces involved can't be too bad, even with a foot & half of gearstick. I'm imagining a kind of sandwich of CNC cut plates & possibly a scrap gearbox to serve as a welding jig.

 

I know Mr Guess is planning to get them recast.

 

 

 

 

Mr. Calver overtook Mr. Guess

 

Gearbox (calverst.com)

[Spider]

 

I've thought about this on and off many times. I'd make a fixture for sure, it would just make the job so much easier and repeatable. While they could be machined in a lathe, I'd most likely do them using the Fixture in the Rotary Table on the Mill. I'd say the factory most likely had a cutter that would have done both faces of the fork in a single operation, though, to maintain precision and finish, I'd only at one side at a time.

 

 

 

Sure, I'm just trying to brainstorm (fart) a least cost 'n most amateurish way to do it. Agree, the best solution  would be for some kindly expert machinist to gather up all the dead ones and do a batch of 'em 

 

If you were try a replaceable face approach, might it be easier to fab up some sort of carrier, a bit like a brake caliper & pad arrangement?

The forces involved can't be too bad, even with a foot & half of gearstick. I'm imagining a kind of sandwich of CNC cut plates & possibly a scrap gearbox to serve as a welding jig.

 

 

Doing them - no matter which road is take - as a batch is definitely the way forward to make them worthwhile if yr concerned with the scale of economics.

 

I had considered in the case of the replaceable faces that a standard fork may not have enough meat where it's needed. If a carried was made, it could be done in steel for sure.

 

Having them cast up is fairly inexpensive, but there are a few machining operations. I think at that point, while a fixture would still likely be needed, machining them by CNC would be the go.
 

[gaspen]

After some research I learnt that it really needs to know the exact materials of the forks. I know some company for this task but couldn't contact them - yet.

 

Without this info there is a risk of a bad welding/soldering and it could fell off.

 

But finally I purchased a pair of NOS forks which fit nicely to the rings. Both are spanish castings, hence there is  "NMQ-BMC" marking on them. They are a little bit different compared to the english forks. These forks have full contact surfaces.

 

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[gaspen]

I want to tell you folks

What I learnt about the forks

 

I spent my day in the workshop with my new forks. I just put in the two new pieces then the assembled 3rd motion shaft.

 

This what I saw : the syncro hub won't sit in the fork. I thought that I made a mistake but did not find any.

 

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After many put-in/take-out I examined the forks. Look the picture on th e left : the 3/4 fork is not on the same axle as the 1/2. Also the selecting rods are in a weird position.

 

Fortunately I have one more good 3/4 fork which saved the situation. See the picture on the right 

 

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[imack]

I had exactly the same problem with a NOS 3rd/4th gear selector fork for a 22g1128 box. It appeared that the securing bolt hole had been drilled slightly out of position. Ended up refitting the Minispares reproduction item.
The NOS 1st/2nd fork was perfect.

[gaspen]

I had exactly the same problem with a NOS 3rd/4th gear selector fork for a 22g1128 box. It appeared that the securing bolt hole had been drilled slightly out of position. Ended up refitting the Minispares reproduction item.
The NOS 1st/2nd fork was perfect.

 

What is your opinion about the MiniSpares product ?

[imack]

I bought mine from minispares about 7 years ago, so things might be different now.
I had to return the first 3rd/4th selector as it was miss-machined. The 1st/2nd selector had excess clearance with the hub, but I ran with it until I got a NOS genuine one (which fitted perfectly)
The 3rd/4th minispares selector I currently have is very good.