Screw Supplies

[David Hill 5Participant @davidhill5]

[David Hill 5Participant @davidhill5]

I am quite new to model engineering and am following drawings that specify an M8 socket cap screw with 0.75 pitch. I made the mistake of buying, at great cost, the taps (and a die too) before I bought the screws. I now cannot find any supplier of the screws! I have tried the usual suppliers and even Emkay cannot help me. Can anyone suggest a supplier that maybe I haven't tried?

Thanks in advance,

David

[JasonBModerator @jasonb]

I suppose as you have the die you could buy a long M8 cap screw that has a portion of plain shank and thread that to the finer pitch.

Out of interest whats the engine?

[V8EngParticipant @v8eng]

You could try here.

**LINK**

[David Hill 5Participant @davidhill5]

Thanks guys, have sent off an email to E C Pitcher, hope they can help. I had thought about cutting the thread from a blank part of a coarser thread but was seeking an easier way!

The engine is actually a steam launch engine. It is a Taylor Twin of 2.5" bore so not sure it comes under the "model" engineering label. The very fine thread is needed for the main split bearings.

David

[JasonBModerator @jasonb]

They are probably sold as spare parts for some form of engine big ends so hard to find when just looking for screws but easy if you have a part number. You quite often find the fine and extra fine pitches used for this sort of thing.

[LambtonParticipant @lambton]

I wonder if the designer of the engine ever found any M8 x 0.75 cap screws?

I was always taught to check the availability of commercially made fasteners and components before finalising any design. On the odd occasion where difficult components were essential, ensure I had found a supplier prepared to make them at an affordable price. These points are not always appreciated by customers, arty designers or inventors.

Just because there is an ISO standard for a particular fastener, in this case M8 x 0.75, it does not mean that any components are manufactured to it unless there is sufficient general demand. The same applies to BS and other specifications for steel, aluminium etc.

[JasonBModerator @jasonb]

Have you tried asking on the Steamboating forum engine section.

Cap heads seem a bit odd for split bearings, I would have though studs with nuts & locknuts so you can adjust the bearings?

Was it an imperial design that has been converted to metric?

[Michael GilliganParticipant @michaelgilligan61133]

David,

It looks like some bicycles use that extra-fine thread.

See here

Also … Aerospace fasteners, here 

MichaelG.

Edited By Michael Gilligan on 22/09/2015 10:41:40

[Anonymous]

Since you have the taps and die it should be trivial to make the required bolts, or studs and nuts. Alternatively change to a different thread; 5/16" BSF for instance?

Andrew

[David Hill 5Participant @davidhill5]

Thanks to all for your words of wisdom all of which is taken onboard. To answer JasonB, yes, the drawings have been converted to metric and I am in the SBA. I think that I will instead use studs with nuts, all of which I can make myself. Thanks for all your inputs.

David

[peak4Participant @peak4]

Just off to the pub, so a very brief reply;

Any good?

**LINK**

[Michael GilliganParticipant @michaelgilligan61133]

Posted by bill williams 3 on 22/09/2015 22:16:18:

Just off to the pub, so a very brief reply;

Any good?

**LINK**

.

Whoo Hoo … deja vu

MichaelG.

[peak4Participant @peak4]

Posted by Michael Gilligan on 22/09/2015 23:20:07:

Posted by bill williams 3 on 22/09/2015 22:16:18:

Just off to the pub, so a very brief reply;

Any good?

**LINK**

.

Whoo Hoo … deja vu

MichaelG.

Ah, knew I should have waited until I had more time to read everything properly; so much for posting in a rush

I'd check out motorcycle dealers too, though that was probably mentioned earlier as well.

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