source for pedal thread taps?

....still working on setting up kid's cranks on the tandem. the cranks I
ended up getting are 155mm, and I'd really like to have the 125mm
option for the 6yr old, and would prefer the more elegant solution of a
second set of holes for the pedals rather than the external crank
shorteners....

I'm not too worried about the 8 yr old overpowering the cranks with the
extra hole, so am thinking that if i can line up the left/right taps, I
can get a local machinist to do the job.

....so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

thx,
d

botfood wrote:

...so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

9/16" x 20tpi (most adult bikes)
1/2" x 20tpi (usually seen in one-piece cranks)

Park Tool has taps:
http://tinyurl.com/gfo6y
and
http://tinyurl.com/jjpbk


Tom Ace

Tom Ace wrote:
botfood wrote:

...so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

9/16" x 20tpi (most adult bikes)
1/2" x 20tpi (usually seen in one-piece cranks)
------------------------

amazing... now you have me wondering why the standard thread on pedals
is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
that the threads would be cut to some metric size, making the taps hard
to come by....

d

botfood wrote:
Tom Ace wrote:
botfood wrote:

...so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

9/16" x 20tpi (most adult bikes)
1/2" x 20tpi (usually seen in one-piece cranks)
------------------------

amazing... now you have me wondering why the standard thread on pedals
is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
that the threads would be cut to some metric size, making the taps hard
to come by....

d

remember that the left crank is left-hand thread.

Pedal threads are about the most standardized things about bike parts.
Sheldon has a good explaination in his glossary:
http://www.sheldonbrown.com/gloss_p.html

Jeff

JeffWills wrote:
remember that the left crank is left-hand thread.
Pedal threads are about the most standardized things about bike parts.
Sheldon has a good explaination in his glossary:
http://www.sheldonbrown.com/gloss_p.html
----------------------

I understand the left/right, but am amazed that the thread diameter and
pitch remains english while virtually every other part, thread, nut and
bolt on bikes is metric.

d

botfood wrote:
...still working on setting up kid's cranks on the tandem. the cranks I
ended up getting are 155mm, and I'd really like to have the 125mm
option for the 6yr old, and would prefer the more elegant solution of a
second set of holes for the pedals rather than the external crank
shorteners....

I'm not too worried about the 8 yr old overpowering the cranks with the
extra hole, so am thinking that if i can line up the left/right taps, I
can get a local machinist to do the job.

...so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

We've got 'em: http://sheldonbrown.com/harris/tools/tap.html

If you do this, I strongly advise you to cut off the ends of the cranks
so nobody will be tempted to use the original holes for an adult at some
later time.

You might also want to consider using the smaller (1/2") size and buying
appropriate pedals.

Sheldon "Stokid" Brown
+------------------------------------------------+
| Love at its best means marriage, and it is |
| altogether the most beautiful thing in life |
| -- William Dean Howells |
+------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

On 6 Jun 2006 19:51:31 -0700, "botfood" wrote:


Tom Ace wrote:
botfood wrote:

...so, anybody have a source for the taps, or know the exact specs
(thread/pitch) so i can look them up in a tool catalog?

9/16" x 20tpi (most adult bikes)
1/2" x 20tpi (usually seen in one-piece cranks)
------------------------

amazing... now you have me wondering why the standard thread on pedals
is US 9/16 while the wrench used is metric 15mm ?! I thought for sure
that the threads would be cut to some metric size, making the taps hard
to come by....

They're still hard to come by. That's not a standard thread pitch for
either the 1/2" or the 9/16" diameter. And then there's the left-hand
thread on one side...
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On 7 Jun 2006 06:40:06 -0700, "botfood" wrote:


JeffWills wrote:
remember that the left crank is left-hand thread.
Pedal threads are about the most standardized things about bike parts.
Sheldon has a good explaination in his glossary:
http://www.sheldonbrown.com/gloss_p.html
----------------------

I understand the left/right, but am amazed that the thread diameter and
pitch remains english while virtually every other part, thread, nut and
bolt on bikes is metric.

The pedal threads were standardized a very long time ago, and the only
recent change was to use metric spacing on the wrench flats.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

botfood wrote:
JeffWills wrote:
remember that the left crank is left-hand thread.
Pedal threads are about the most standardized things about bike parts.
Sheldon has a good explaination in his glossary:
http://www.sheldonbrown.com/gloss_p.html
----------------------

I understand the left/right, but am amazed that the thread diameter and
pitch remains english while virtually every other part, thread, nut and
bolt on bikes is metric.

d

Well... Campy axles are 26tpi (threads per *inch*). It's a long story
that's been posted before.

And *don't* get started on tire sizes!

Jeff

Sheldon Brown wrote:
botfood wrote:
...still working on setting up kid's cranks on the tandem.
....
We've got 'em: http://sheldonbrown.com/harris/tools/tap.html
You might also want to consider using the smaller (1/2") size and buying
appropriate pedals.
-------

looks good, I'll check my stock of tiny bikes, I am pretty sure at
least one of them has the 1/2 pedals, which would leave a little more
meat on the crank....

d