What thread is it?

[Martin DowingParticipant @martindowing58466]

I have measured thread of a bolt for which I will need to fabricate nut, so it will be necessary to purchase appropriate tap for this job.

So OD is 0.3" (7.64mm) and 28TPI.

I have failed to find such a thread in my reference booklet.

It that a standard thread (and if so, what it is) or perhaps something weird, non standard?

[Martin DowingParticipant @martindowing58466]

Identification of thread

[KWILParticipant @kwil]

What is the thread angle? It looks close to a slightly worn 5/16" x 28UN. What is the bolt from?

[Speedy Builder5Participant @speedybuilder5]

Hi there Martin, Can you give a bit more information. What is the thread used for (sewing machine, photographic etc). The fractional size is about 19/64" (0.2969&quot, but the OD would normally be a little smaller than the the nominal OD size on a worn bolt. Can you guess the age of it which may give a clue perhaps.
BobH

[David Standing 1Participant @davidstanding1]

If it is 55 deg thread form, then 1/16" BSP 

You'll have to search hard for it, it doesn't appear on many thread charts 

 

 

 

 

Edited By David Standing 1 on 10/09/2017 16:23:10

[KWILParticipant @kwil]

What equipment is it from??

[Howard LewisParticipant @howardlewis46836]

28 tpi immediately made me think of 1/8 BSP, but the tapping size of 8.8mm is bigger than 0.3"

David standing 1 is correct.

Looking at "BSP THREADS" on Google, you will find 1/16" BSP as 0.304 OD, 28 tpi, tapping size 6.6mm.

Howard

[Martin DowingParticipant @martindowing58466]

Hi,

The thread is from an end of brass pipe screwed to the base of RDG oiler for ML7. This pipe with small holes nearly bottom, oil pass down through these holes down to sight tube.

Unfortunately it is impossible to tell, is it 55 or 60 deg, because it is (like many other items from RDG) quite badly formed. Angle seems to be somewhere between, flanks of thread are torn while new and pipe has taper 4 thou per INCH.

So weighing all evidence, it is probably 1/16" BSP.

NB. Poor engineers from old Myford are turning in their graves or getting very upset in their old age seeing so badly made stuff sold under this brand.

[David George 1Participant @davidgeorge1]

Hi it is 1/16 BSPT tapered thread

David

[Martin DowingParticipant @martindowing58466]

No, it cannot be.

About 2/3 inch is threaded from one side of pipe but there is taper on entire lenght of pipe, threaded or not.

Tapered threads are not this long anyway and taper is steeper.

From second side (one which srews into base of oiler) only few turns are made with the same thread and thread doesn't look tapered.

[David George 1Participant @davidgeorge1]

How about a picture to show problem?

David

[Ian HewsonParticipant @ianhewson99641]

Or just bash rdg?

[roy entwistleParticipant @royentwistle24699]

Why shoot the messenger? RDG will not have made the part in question, Maybe they should have checked, but can you honestly expect them to scrutinize every item they sell? The lads are doing a good job trying to keep the marque going

Roy

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