Screw Supplies

This topic has 13 replies, 7 voices, and was last updated 23 September 2015 at 00:37 by peak4.

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22 September 2015 at 09:24 #7811
David Hill 5
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@davidhill5
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22 September 2015 at 09:24 #205256
David Hill 5
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@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
22 September 2015 at 09:32 #205258
JasonB
Moderator
@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?
22 September 2015 at 09:34 #205261
V8Eng
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@v8eng
You could try here.

**LINK**
22 September 2015 at 10:14 #205266
David Hill 5
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@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
22 September 2015 at 10:20 #205267
JasonB
Moderator
@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.
22 September 2015 at 10:26 #205270
Lambton
Participant
@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.
22 September 2015 at 10:30 #205272
JasonB
Moderator
@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?
22 September 2015 at 10:38 #205273
Michael Gilligan
Participant
@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
22 September 2015 at 11:07 #205277
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
22 September 2015 at 11:41 #205283
David Hill 5
Participant
@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
22 September 2015 at 22:16 #205367
peak4
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@peak4
Just off to the pub, so a very brief reply;

Any good?

**LINK**
22 September 2015 at 23:20 #205378
Michael Gilligan
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@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.
23 September 2015 at 00:37 #205383
peak4
Participant
@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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