Author Topic: Threads  (Read 336 times)

Threads
« on: January 06, 2019, 03:19:23 pm »
I'm having a try at making a home made derailleur alignment tool, to be used on a Hewitt all steel frame. But before I try to use a 10mm bolt in the threads of the hanger,Is this the correct bolt size and thread pitch?, or will I strip the threads by using this bolt. I don't want to spoil the frame using an incorrect bolt. Thanks for any help.

LittleWheelsandBig

  • Whimsy Rider
Re: Threads
« Reply #1 on: January 06, 2019, 03:31:39 pm »
10 x 1 will work fine on 10 x 26tpi hangers. The difficult part is getting tight enough clearances on the bolt to stop the alignment tool from flopping about too much.
Wheel meet again, don't know where, don't know when...

Re: Threads
« Reply #2 on: January 06, 2019, 03:54:36 pm »
Most derailieurs are 10mm X 1mm thread rather than the coarser 10 x 1.5mm thread of an M10 bolt.

You might be able to use a bit of axle, which are often 10 x 1 mm pitch too.
If it ain't broke, fix it 'til it is...

Re: Threads
« Reply #3 on: January 06, 2019, 04:56:25 pm »
to avoid loading up the threads on the hanger, it is much the best idea if you clamp the gear hangar between two track nuts on an M10x1 axle.

My favoured DIY method is to use two rear wheels, each with M10x1 threaded axles. The first is put in the frame with the sprockets on the left; this makes room for the other one to be bolted through the gear hanger and used as a tool/gauge for resetting it.

The first wheel makes sure that the dropout doesn't bend where you don't want it to (the clamping force of track nuts is about x3 more than a typical QR). It is relatively easy to see when the two wheels are parallel to one another and the gear hanger is properly aligned.

FWIW the tolerances specified by shimano are 0 to 0.5degrees, so 0.5 degree 'toe out' and 'negative camber' in horizontal and vertical planes respectively is tolerated. Any error in the reverse direction always degrades shifting, which is why it soon goes bad if the bike falls over.

0.5 degrees means there will be 5mm difference in the separation of the two wheels across a full (622mm) wheel rim diameter.

cheers

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Threads
« Reply #4 on: January 06, 2019, 06:53:03 pm »
Most of my repairs are low end, utilitarian stuff - Carrera, B-Twin, Pinnacle etc.

I don't have a hanger alignment tool but use a solid cr-mo M10 axle with spacer and lock nuts set so that around 12mm of thread protrudes to screw in to the hanger.

With the bike in the stand remove the mech but leave the wheel in place - if the hanger isn't firmly clamped by the wheel you're not going to bend the right bit - screw the axle in place of the mech and weigh it up as a pointer. The pointer needs to be parallel to the wheel axle. Slip a thin wall, straight handlebar over the pointer and gently bend it in the right direction.

I will always point out to the customer that this might result in a broken hanger and if it does it's a chargeable part. I can't recall more than a handful that ended badly and I have done hundreds.
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Threads
« Reply #5 on: January 06, 2019, 06:58:30 pm »
Please note that 10x1mm is not a common, generally available 10mm thread. It is not the same as the normal 10mm fine thread which is 10x1.25 IIRC. Therefore please go down the rear wheel axle route unless you have access to non-normal thread sizes.

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Threads
« Reply #6 on: January 06, 2019, 07:01:46 pm »
What he said...
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Threads
« Reply #7 on: January 06, 2019, 08:00:14 pm »
M10 x 1.0 isn't too hard to find but you must specify the " x 1.0" bit.  I've just bought some M10 x 1.0 nuts because I don't want* to saw my track wheel axles (Miche Primato) flush with the track nuts as specified by Calshot - easier to just thread an extra nut on each side if they're bothered about the pointy axle.

*thus rendering the wheels useless in any frame with thicker track ends than the Harry Quinn, which has fairly basic plate ends.
Never tell me the odds.

Re: Threads
« Reply #8 on: January 07, 2019, 07:53:45 pm »
thank-you for the help and tips. This afternoon I used a old rear wheel axle and it ran through the hanger smoothly so I will try tomorrow to do the job.I think that the rear mech is more out of true than the hanger,but it is a good starting point to check the hanger.

Re: Threads
« Reply #9 on: January 07, 2019, 08:07:22 pm »
do bear in mind that many rear wheel axles are 3/8" diameter, a bit smaller than 10mm, so will go through the hanger even if the pitch is wrong; if you don't use a nut both sides of the hanger eye with this kind of axle, you will very easily strip the threads in the hanger.

cheers