Fork Leg Remedial Fix

[Joolstacho]

R, I don't know if it's the same size tubing as BSA, I should be able to check,- out in the workshop -I think it's called 'cold drawn seamless tubing'.
And I think it's used for hydraulic rams on heavy machinery nowadays. Obviously the inner diameter needs to be close to perfect.
And I don't know how the top and bottom lugs are attached on a BSA - perhaps brazed? My guess is that Velocette would have used soft solder for low temperature therefore no distortion.
I got it from Criterion Engineers in England. I'll get back to you mate.

[Joolstacho]

Richard. It's Criterion (Engineers), Greenoak, Bishopstone, Swindon, Wilts. I've forgotten the contact's name, sorry, but I could probably track him down via the Velo Club.

Measurements - (I get - metric) Stanchion OD : BSA 34.56, (below stepped section)  Velo 31.4.
Slider OD BSA 41mm,  Velo 38.2
Slider ID  BSA 37.53,  Velo 34.7 (approx)

All measurements approximate and subject to confirmation!

-Jools

[RichardL]

Rarely seen in the wild.

Richard L.

[Joolstacho]

Aha! all you need now is a wild unworn slider...

[RichardL]

Jools,

I talked to Stuart regarding new BSA slider tubes. He can't help there, but was helpful with some process info. I'm calling him again on Monday regarding using DOM, which I can find, vs. CDS, which I cannot. Any opinions on that?

Richard L.

[Joolstacho]

Richard, CDS I get (Cold Drawn Seamless) But DOM? sorry, my command of acronyms started to decline with DOS ! 
I do think that tubing used for hydraulic rams etc is the thing.

[RichardL]

DOM is welded, cold drawn over mandrel. I understand what you mean about hydraulic cylinders, but I am thinking our fork legs don't have to endure comparable forces.

Richard L.

[Joolstacho]

True Richard, but they do have to have dead smooth and dimensionally accurate I.D. eh. Perhaps not as perfect as hydraulic rams though, we're dealing with sliding bushes, not hydraulic pistons.
Are the tubes brazed to the lugs? Maybe silver solder? The Velo can use soft solder (Roofers or lead solder we call it down here, not the electrical type) because there's a much longer fitting overlap, something like 40mm from memory.
(So DOM is Drawn Over Mandrel - goddit!)

[RichardL]

What! you're still talking about this?!

Here is a sweet little photo of the family gathered for the holidays and a photo of Cousin Tubey, the Elder. I don't believe there will be a Cousin Tubey Jr. in the near future, as the cost to implement that relationship in material, machining, welding and painting is likely above $250. Each of the bits was an RPA to extract from Tubey and cleanup. However, regardless of all the time and money already in it (a lot of learning time, hard labor, oxy-acetylene cost, etc.) I've opted for the best used part I could find, and that wasn't cheap, either.  I figure it offers the best possibility for riding in early spring (though, I've never heard of a fork leg controlling the weather).

Richard L

[Joolstacho]

Richard, as we know, cooling is a very good thing, but perhaps cousin Tubey has taken it a bit far?

[RichardL]

The fastest way to a bracketectomy.

Richard L.

[Joolstacho]

Eeeek! That sounds painful mate!

[RichardL]

It's taken way too long, but I'll finally get to put my front end back together this weekend. Having trouble choosing between NOS powder-coated fork leg and deconstructed.  Kind’a hard to get a good picture of how good the NOS looks inside.

Richard L.

[chaterlea25]

Hi Richard,
I'm sure there are loads of topics on here on fork reassembly but may I add or repeat one or two "tricks"

Fit the top bush and circlip in the slider to check if shims are needed before you assemble the stanchion
If only a very thin shim is needed, it is a better idea (in my opinion) to machine the top of the bush lip in order to fit
a 15 or 20 thou shim, the idea being is that they will survive the punishment that breaks up thin shims

A trick I use when fitting the circlips is to use a 4 inch point nose vice grip and a piece of shim or thick gasket paper
When you push down one end of the circlip hold that end down with one jaw of the grips and use the shim/paper to protect the seal holder threads and clamp the grips in line with the slider, NOT TOO TIGHT! , then work your way around the circlip pushing it down into the groove, I use two small screwdrivers for this

John

[RichardL]

Fit the top bush and circlip in the slider to check if shims are needed before you assemble the stanchion
If only a very thin shim is needed, it is a better idea (in my opinion) to machine the top of the bush lip in order to fit
a 15 or 20 thou shim, the idea being is that they will survive the punishment that breaks up thin shims

A trick I use when fitting the circlips is to use a 4 inch point nose vice grip and a piece of shim or thick gasket paper
When you push down one end of the circlip hold that end down with one jaw of the grips and use the shim/paper to protect the seal holder threads and clamp the grips in line with the slider, NOT TOO TIGHT! , then work your way around the circlip pushing it down into the groove, I use two small screwdrivers for this

John,

These are good tips. It never occurred to me that the top bush may need to be shimmed. Not sure I understand the need, especially if I'm not doing motocross (which I also know nothing about). On first read, I thought, "Are you kidding, struggle the circlip in place just to measure for the shim?" Then, I remembered that the stanchion wouldn't be in there, so, little trouble. My left fork is already assembled and on the bike, so it's not coming apart for a shim check, but I may do it with the new one, if for no other reason than to see how loose they could be. Though, you would expect the NOS to be a better fit.  (It was only after the left fork was installed, and I went to install the new right one, that I realized I ordered the wrong style right slider. Lost three weeks, but the new one, being NOS, and not "reconditioned," is a big bonus.)

Wish I had a needle-nose vice grip for the final circlip installation, but I don't, so it will, again, be just a two-screwdriver struggle.

Thanks for teaching.

Richard L.