1/6″ x 28tpi tap & die.

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1/6″ x 28tpi tap & die.

This topic has 25 replies, 12 voices, and was last updated 16 August 2017 at 18:57 by speelwerk.

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12 August 2017 at 20:45 #311699
speelwerk
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@speelwerk
Perhaps someone knows a supplier for tap & die 1/6" x 28 tpi. I have tried to find one with no luck. Niko.
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12 August 2017 at 20:45 #13028
speelwerk
Participant
@speelwerk
12 August 2017 at 20:51 #311700
JasonB
Moderator
@jasonb
Do you mean 1/4" x 28 as that would be UNF?
12 August 2017 at 20:56 #311702
speelwerk
Participant
@speelwerk
Posted by JasonB on 12/08/2017 20:51:49:

Do you mean 1/4" x 28 as that would be UNF?

No, I am looking for 1/6" x 28, if it exists.
12 August 2017 at 21:01 #311703
JasonB
Moderator
@jasonb
I don't know of anything around that dia 0.167" with such a coarse pitch

An 8-30 gauge american screw is close on diameter at 0.164" but even the rare UNS special pitch is only 30tpi

I can;t think of any standard that uses 1/6"

What is it for? Could it be a pipe thread where the 1/6" refers to teh bore as 28tpi may be about right for that and also right for 1/16" if there is a typo

Edited By JasonB on 12/08/2017 21:04:53
12 August 2017 at 21:16 #311706
speelwerk
Participant
@speelwerk
It must be some kind of Swiss size from 1870. It is used much in musical boxes from that period. Many times the thread on the screw is gone and I have to thread cut new ones which takes too much time or use an oversize which is not ideal. Niko.
12 August 2017 at 22:19 #311707
Michael Gilligan
Participant
@michaelgilligan61133
Niko,

This table includes the Thury threads:

http://pages.cs.wisc.edu/~bolo/workshop/thread.html

… but still nothing to match your spec.

It looks very much like a special.

MichaelG.

.

P.S. … is it a full form thread ?

Just wondering if it could be a truncated form of the Thury #1
12 August 2017 at 22:34 #311708
speelwerk
Participant
@speelwerk
Thanks for the help, however it is a full form thread. Niko.
12 August 2017 at 23:23 #311710
not done it yet
Participant
@notdoneityet
Swiss? 1870? I would not have thought they were using Imperial measurements a great deal – although sock machines and other similar inventions did tend to comply to the UK/US sizes. Or maybe the movements were Swiss and the container made somewhere else?
12 August 2017 at 23:36 #311712
Clive Foster
Participant
@clivefoster55965
1870 pre-dates compulsory metrication, metric was optional from 1868 and compulsory from1877, so the thread could well have been specified in the old Swiss system. Almost certainly an in-house or local thread used by a single manufacturer or group of firms from the same area.

The old Swiss base unit for smaller measures was the pied (fuss) re-defined as 0.30 metres for the transition to metric but subject to local variations. Next down is the pouce at 1/12 th of a pied followed by the linie at 1/144 th of a pied or 1/12 th of a pouce.

Pied and pouce are essentially same as Imperial foot and inch so 1/6 inch diameter is likely to have been 2 linie in the old system. Which is sensible.

The 28 tip pitch doesn't appear to be related to the Thury system, which wasn't defined until 1877 or thereabouts. Thury devised the system as a standardisation of "useful" mathematically related threads close to those commonly used in the watchmaking industry. 28 tip is close to the pitch of a no 1 but the diameter is nearly mid-way between 2 and 3. Sounds too much of an outlier for one of the close to threads previously used.

Clive.
13 August 2017 at 03:52 #311720
Hopper
Participant
@hopper
I wonder if Tracy Tools or The Tap and Die Company that advertise in the back of MEW would make special orders such as these?
13 August 2017 at 08:57 #311729
SillyOldDuffer
Moderator
@sillyoldduffer
You could make a tap and die to suit from silver steel. The picture shows a home made tap.

To make it I turned a length of silver steel (aka drill rod) down to the required diameter and lathe cut a thread in the usual way. Then I milled the relieving slots and squared the driving end. After the usual heat treatment the tap works surprisingly well considering how crude it is.

Once you've got a hardened tap it wouldn't be difficult to make a silver steel die with it.

Obviously home-made won't last as well as the real thing but they do work. If you mend lots of music boxes it would be worth making a batch.

Dave
13 August 2017 at 09:46 #311739
Phil P
Participant
@philp
Niko

Are those the screws that hold the comb onto the bedplate that you are trying to replace ?

I too have had trouble finding an exact match and have resorted to making slightly larger ones. I have looked for these sizes for around twenty years with no luck.

I wondered if you make your own gears for the governors as well ? I have also been looking for 0.32 & 0.38 Module gear cutters with no luck either.

Phil

P.S. If you run short of musical boxes to restore, I know where there are plenty of them !! (In my loft)
13 August 2017 at 11:25 #311759
speelwerk
Participant
@speelwerk
Yes Phil, those are the comb screws, you would like to keep it as original as possible but they can have had a hard live giving you no other option then to make slightly larger sized ones. The 0.32 & 0.38 mm module is another of those problems, you can try this one **LINK** . I use a 19th century rounding-up machine and cutters to make it mesh the other gear in the governor. It goes a little over 0.40 mm modern module but the Swiss must also have had rounding-up machines for large size wheels, but sofar never found one. I think your loft will look similar to mine. Niko.

Edited By speelwerk on 13/08/2017 11:26:01

Edited By speelwerk on 13/08/2017 11:27:22
13 August 2017 at 12:58 #311778
Ian S C
Participant
@iansc
I/16" x 28 TPI would be neared to the pitch of a wood screw.
Wood screw sizes. #0 !/16 x 32 TPI. #1 5/64" x 28 TPI. #2 3/32" x 26 TPI.

Ian S C

Edited By Ian S C on 13/08/2017 13:06:53
13 August 2017 at 14:11 #311795
Brian Sweeting 2
Participant
@briansweeting2
Have you tried Wiseman Threading Tools,Â **LINK**

They offer a "specials" service.
13 August 2017 at 16:10 #311809
bricky
Participant
@bricky
The tap was possibly made in their workshop and then a screw plate made from it and not to difficult to harden if gauge plate or an old file annealed drilled and tapped and rehardened.

Frank
13 August 2017 at 16:54 #311819
mick
Participant
@mick65121
Why not a 1.5M same meat, different gravy, but easier to source..
13 August 2017 at 19:59 #311845
Michael Gilligan
Participant
@michaelgilligan61133
Posted by mick on 13/08/2017 16:54:17:

Why not a 1.5M same meat, different gravy, but easier to source..

.

I think because the required diameter is 1/6" … which is about 4.23mm

MichaelG.
14 August 2017 at 17:32 #312005
mick
Participant
@mick65121
Hi. Michael. 1.5mm divided by 25.4 = 0.059'' If you want to argue over 0.003'' on a screw thread be my guest, but for practical engineers its a practical answer.
14 August 2017 at 18:32 #312015
Michael Gilligan
Participant
@michaelgilligan61133
Posted by mick on 14/08/2017 17:32:51:

Hi. Michael. 1.5mm divided by 25.4 = 0.059'' If you want to argue over 0.003'' on a screw thread be my guest, but for practical engineers its a practical answer.

.

Mick,

I don't want to argue with anyone about anything.

… but I simply don't understand your suggestion.

The screws on Niko's box are one sixth of an inch diameter.

MichaelG.
14 August 2017 at 19:02 #312023
JasonB
Moderator
@jasonb
Mick I think you read the title as 1/16" not 1/6" ONE SIXTH

Even then M1.5 is not a standard size so would be a special, M1.6 is.
14 August 2017 at 21:15 #312046
Phil P
Participant
@philp
Jason

You are right he does indeed mean ONE SIXTH or approx M4.2 in metric.

Victorian cylinder musical boxes have some very strange threads. In fact they can vary in size on the same instrument and it's not wise to get any screws mixed up when trying to re-assemble one.
I reckon they were all hand made and no two were exactly the same

Phil

Edited By Phil P on 14/08/2017 21:18:03
16 August 2017 at 14:44 #312330
speelwerk
Participant
@speelwerk
OK, not the greatest engineering event making 10 screws of 1/6" x 28, but musical box restoration is much donkey work before it gets interesting, on the rigth is one of the damaged original screws. Asked a quote for a special made die, if they give it will I let it know. Niko.
16 August 2017 at 17:07 #312347
Phil P
Participant
@philp
Niko

The 28 tpi is very close to 0.9mm pitch.

Probably not a solution to your immediate problem, but I have loads of spare M5 x 0.9 taps if you would like any.

Phil
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