Tap and Die

This topic has 8 replies, 7 voices, and was last updated 29 March 2019 at 18:23 by mark costello 1.

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29 March 2019 at 08:53 #402647
Peter Love 1
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@peterlove1
Hi all I have a Jones iambic Morse paddle in my collection, it was manufactured in the USA until 1998, the screw threads are 3/16" NF 50 (very fine) I am unable to track down a tap and die of that size, does anyone know were I might find a set, I would even consider a complete set that contains this size if there was no other alternative.

Peter Love ( Amateur Radio call G0KOK )
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29 March 2019 at 08:53 #26517
Peter Love 1
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@peterlove1
29 March 2019 at 09:16 #402651
JasonB
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@jasonb
An American thread of 3/16" nominal size would tend to use a number as just about all their threads under 1/4" do in this case a #10 would be correct.

Are you sure it is 50tpi and there is a #10-48 UNS or the finer #10-56 UNS both of which you can buy taps for.

Edited By JasonB on 29/03/2019 09:21:43
29 March 2019 at 09:38 #402653
Rik Shaw
Participant
@rikshaw
I have drawn a blank on that size – perhaps it is a special. These people will make specials in 24 hours but I suspect the price will make your eyes water.

Rik

**LINK**
29 March 2019 at 09:57 #402659
Nicholas Farr
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@nicholasfarr14254
Hi Peter, as Jason has pointed out, the NF, NC, UNF and UNC don't do a standard for under 1/4", you can get Unified screw threads under 1/4" for attachment purposes and ANC/ANF but these are gauge sizes and none of them match what you want. If it is 3/16 x 50 T.P.I. then it is quite likely to be a special fine pitch, which would be made to order. Warrior used to do such taps but not die's (I don't know if they still do though). I guess the male thread would have been machine cut.

Regards Nick.
29 March 2019 at 10:05 #402660
SillyOldDuffer
Moderator
@sillyoldduffer
Agree, triple check the size. I can't find anything in 50tpi.

NF was made obsolete in 1949 but it is interchangeable with UNF, dimensions here.

If it is a standard size, not 3/16" x 50, Tracy Tools are a good source and they might be worth asking. They do have 3/16" x 60tpi.

However, 3/16" x 50tpi is suspiciously close to Metric M5 fine, which would probably fit:
- 3/16" = 4.8mm
- 50.8tpi = 0.5pitch
It is possible that a US maker might have used a metric thread. Or, they're a bunch of sods who used a non-standard thread to guarantee parts sales!

Dave

PS Can you post a photo of your Iambic Paddle please? Morse keys have a fan-base!

Edited By SillyOldDuffer on 29/03/2019 10:09:25
29 March 2019 at 10:26 #402663
Nicholas Farr
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@nicholasfarr14254
Posted by SillyOldDuffer on 29/03/2019 10:05:38:

Agree, triple check the size. I can't find anything in 50tpi.

NF was made obsolete in 1949 but it is interchangeable with UNF, dimensions here.

Dave

Hi Dave, with the exception of I" NF/UNF. 1" NF 14 T.P.I. 1" UNF 12 T.P.I. and don't ask how I found out.

Regards Nick.

Edited By Nicholas Farr on 29/03/2019 10:28:42
29 March 2019 at 10:35 #402665
Brian G
Participant
@briang
There is a 3/16 x 50 die on eBay right now, unfortunately the seller doesn't state the profile LINK

Brian
29 March 2019 at 18:23 #402721
mark costello 1
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@markcostello1
Victor Machinery in the States are known for sourcing odd ball taps and dies, if a last resort.
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