Helicoil bigger than expected

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11-02-23, 04:52 PM

#26

3alarmer

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Quote:

Originally Posted by sysrq

It's an integrated deraileur hanger. Hard to avoid any cognitive biases but current social status has only allowed to mess with DIY electronics a bit more, since electronic components are smaller then it's harder to damage them mechanically.

Quote:

Originally Posted by sysrq

I haven't drilled anything yet since the original threads still can be tightened up to 10Nm, but they can strip completely at the most inconvenient time. Looks like without drill press it will be impossible to drill and tap it straight anyway. Wasn't sure if Dropout Saver is the best choice since you never know when it will start to interfere with chain or cassette, although it doesn't require the hole to be completely straight.

Quote:

Originally Posted by dedhed

Unless it's really bad misalignment it should be able to be compensated for in derailleur alignment.

... I have done over a dozen of these, and I've never used a drill press. An integral hanger, by definition, will require final alignment by bending it, using a derailleur alignment tool.
That tool threads into whatever threads you have at the moment, in your integral hanger. So I wouldn't worry too much about a drill press.

Use a square to get the drill bit at 90* to the hanger, and you should be close enough. Then you do a final alignment, which is based on your current new threads.

Someone will now doubtless chime in to tell me why this is wrong. I apologize in advance.

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Last edited by 3alarmer; 11-02-23 at 04:56 PM.

11-02-23, 05:24 PM

#27

Black wallnut

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Quote:

Originally Posted by spclark

So you ran an M10x1 Helicoil into an M10x1-threaded hole that still has viable threads innit and you expect the Helicoil to accept the original M10x1 bolt?

If so, it won't - trust me on this. Helicoils are intended to be installed in a smooth-sided bore of a diameter indicated on the packaging they came in. M10x1 'coil needs a 10.25mm hole for aluminum, magnesium, steel and plastic for proper installation.

You could use an X (10.0838mm so will be tight!) or a Y drill (10.2616mm dia.) as a 10.25mm bit might be tough to find. McMaster has 10.2mm for ~ US $27 (shipped) which ought to work OK if you're careful doing the job.

Or have I missed something?

You missed the fact that helicoil repair kits come with inserts, a tap of the required size and an install tool. Your statement about a smooth sided hole is incorrect, or incomplete. Is this due to oversight or ignorance of the method and material?

Quote:

Originally Posted by maddog34

don't bother... it's for deep, blind, coarse thread holes, and is only marginally effective on those..

I have had excellent success with Form-a-thread which was a loctite product sold by Napa when I used it. IIRC I used it for both through holes (nuts) and blind holes. It makes a good permanent and durable repair but not one that I would use for high torque or frequent disassembly. A hanger bolt should be a good application depending on the percentage of remaining threads.

Although drills will follow an existing hole they will also ream off-center if not guided straight. They also are notorious for making holes that are not round.

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