Left Hand Crank Re-threading
 

Does anyone know of a bike shop that does left-hand crank re-threading work? If you do, do you know how much they charge?

I have a left-hand Stronglight crank with stripped threads. There are basically 3 methods of repair:

* Drill out, tap and Heli-coil (or http://ikekin.co.jp/contents/catalog/original/recoil/pricelist-pdf/pricelist.pdf"]Recoil)

* Drill out, tap and fit a https://www.winstanleysbikes.co.uk/product/40232/Cyclus_Replacement_Pedal_Bushes"]bush

* Weld up the hole and tap to 9/16-20.

I've had a right-hand thread Heli-coiled by a local engineering works (cost $60) as the size happens to be the same as a motorcycle spark plug but they don't have a left-handed tap or Helicoil. I would buy them but it seems only kits are available, with 5 X lh coils and 5 X rh coils at around $180 - a bit dear for a once off.

I've contacted 3 shops here in Tokyo but not only do they not do such work themselves, they don't know anyone who can either. I've telephoned 3 shops in the UK and it's the same story. Ideally, I would find someone in the UK as I have family there I could send the crank arm to. Failing that, I know a few people in the US.

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The ELDI brand of bicycle tools from Germany makes a kit for this. It includes reamer and oversized tap for the helicoils which come with the kit. Have done several and they turned out fine. This is a common repair in the trade and one would expect all bike shops to have this kit or a similar one.

Similar sets offered by Dill of England and by Unior:

http://velobase.com/VeloImages/Tools...E6361FE3D.jpeg

http://i.ebayimg.com/images/g/BjEAAO...zS/s-l1600.jpg

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Thanks for the reply but I am specifically looking for a workshop, either in the US or preferably in the UK, which undertakes such repairs. As mentioned in my post, I am aware such kits are available but find them prohibitively expensive when I just want to do a single crank arm.

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Lowest cost solution would be to send to a member who has the tools.

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...I have one of the kits and some of the fittings, and I'm pretty sure I didn't pay a hundred and eighty bucks for it.

The inserts themselves are in the six to eight dollars each range for cost right now. You ought to shop around on the internet for a better price.

https://www.amazon.com/Unior-Pedal-T.../dp/B001PTCKJO

That's a link to the one for sale by Niagara Cycle for 111 bucks plus four or five to ship in the USA. I know things are different in Japan, because it's hard to find distributors for some of the stuff Hozan makes here in the USA.

But I think that if you already spent 60 bucks to do one arm, and now need to do another, an investment of a little over a hundred dollars might be reasonable even if you don't plan on doing any more of them.

By the time you send it to me in California, and I repair it and send it back, you're probably money ahead to just suck it up and buy the kit online.

I'm sure you could buy the kit and use what you need then sell it here to someone.

Hello,

Do you have any contacts in Singapore? There use to be a "vintage" shop there that did these type of repairs. Sorry, I don't remember the name, only that it was being run by the second generation of the family.

Good luck,

Van

If you had the tap I'm sure one of us could send you a helicoil. We have a half dozen of each at our shop.

Thanks everyone! I appreciate you all taking the time to comment.

3larmer pointing out that postage would suck up any saving on the kit if I sent the crank to the US coincided with me discovering that you could buy the taps and inserts separately, so I've ordered a left-hand tap and 3 inserts. I have another crank with the hole not quite square to the crank face that I'm hoping to 'repair' with an insert, and a friend who wants a l-h insert (and now to borrow the tap).

Also coincidentally, the place I found that sold the parts individually was Niagara Cycle Works, the same outfit 3alarmer linked.

Thanks again!

I have a Centurion Dave Scott Expert bought off of CL. It was originally sold from this bike shop.

HIRAKO BIKE SHOP **********?, 249-0006 Zushi-shi, Japan | Retail and consumer merchandise

They are still in business. You might give them a call.

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...on doing the repair: The tool itself is pretty nifty, a combination tapered reamer that ends at the top in a correctly sized tap for the insert. So it's pretty hard to go wrong. But it is possible to get the tap going in at a slight angle if you're not paying attention, and then you're screwed because if you get the hole in at anything other than 90* you'll notice it on the pedal.

So do the repair in a vise, and use a carpenter's angle or some other device to make sure you're at 90* as the tap portion enters the crank. When installing the insert in the hole, it's just made of a very thin sheet material. So I like to use red Loctite (high strength) on the outside of it and use an old pedal spindle of the appropriate threading (L or R) to install the thing, which makes certain it's fully seated in the hole on the outside face. Then carefully remove the spindle.

The inserts are longer than the thickness of some cranks. So after the Loctite dries, mask the crank arm surface on the inside, and carefully remove any excess that sticks out using a bench grinder. You can cut off any excess, and finish it with a file, but a grinder does a slightly cleaner job if you're careful. I usually reinsert the pedal spindle for this operation.

Can a similar tool be used to repair threads stripped by a crank puller? Asking for a friend.

You need a different tool.

Wow, that's expensive. The one I saw was much simpler and cheaper, but of course I can't find it now.

Oh wow. Happy to know it exists, I'll check the local LBS options and see if they have one.

...there was one for a while ( I kept meaning to buy one) that was made by some guys in Portland. Basically, it just retapped the crank puller threads a size larger, and then you used that for the puller for the future.

Simple and adequate solution, and cheaper because you don't have the little insert thingies to make and install.

By the time I went to buy one, there was no response from the business. They either didn't sell enough of them to continue making them or they went belly up in the competitive world of bicycle parts and tool manufacturing.

It still wasn't real cheap, just cheaper. VAR makes one too, but getting VAR tools is a PIA for me as a non-professional with no business account.