Need 6-40 tpi thumbscrew

dr sportster · Mar 20, 2017

I bought a machinist level protractor on ebay and one of the thumbscrews is missing. It has to be 6-40 thread . McMaster- Car only has 6-32 thread thumbscrews. I need to find 6-40 with shoulder thumbscrew. Any ideas ?

JoeM(GA) · Mar 20, 2017

what about using a socket head screw, outer edge is knurled, they show them in 6-40
mcmaster page

Ark68SS · Mar 20, 2017

Grainger-- https://www.grainger.com/category/thumb-screws/screws/fasteners/ecatalog/N-8ndZ1z0o10o

BillL

Ark68SS · Mar 20, 2017

Whoops, that's a 4 x 40

BillL

johndeere720GA · Mar 20, 2017

Click the Link
once at that page select "screws and bolts"
then set the Thread Size to 4-40
They have a bunch of choices.
McMaster Carr thumbscrews

jniolon · Mar 20, 2017

you could also check with some instrument repair and alignment shops.... folks that tend to levels and transits and such... they have a bunch of small many thread stuff... check the yellow pages.

john

Bret4207 · Mar 20, 2017

6-40 is very common in gun work. Try Brownells Gunsmith supply. They aren't going to have thumb screws, but they may be able to provide stock you can use to make your own.

Texasmark1 · Mar 20, 2017

Standard fine thread machine screws are 0-80, 2-56, 4-40, 6-32, (8-32 as I recall), (10-28 as I recall) and (?-28 as I recall....?-20 is the coarse thread). I have a drill and tap guide in the shop with all of it out in the shop. Surely there are specialty threads for things like watches and precision instruments.

Bret4207 · Mar 21, 2017

(quoted from post at 21:47:47 03/20/17)
6-40 is very common in gun work. Try Brownells Gunsmith supply. They aren't going to have thumb screws, but they may be able to provide stock you can use to make your own.

Sorry, my mistake. 6-48 is the real common one. But, Brownells sells 6-40 dies as I said and you should be able to use it to cut down a larger thumb screw.

JOB · Mar 21, 2017

Try the manufacture of the lever protractor

Butch(OH) · Mar 21, 2017

Only other time I have run into 6-40 is the old Weaver saddle type scope ring screws. Not a commonly used thread or sure. I have slotted screws in a box and a tap but no die.

Bret4207 · Mar 22, 2017

I have taps and dies from 2 gauge on up into 18 plus a bunch of metric stuff Dad had for 'smithing on European stuff. I've cut more than one 8-40 down to 6-40 to fit weird stuff.

kevinstuff · Mar 22, 2017

If it is Starrett brand , just order from
them , I ordered a bunch of lost
parts and they were great to buy from
and the cost was low

Need 6-40 tpi thumbscrew

dr sportster

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JoeM(GA)

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Ark68SS

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Ark68SS

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johndeere720GA

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jniolon

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Bret4207

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Texasmark1

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Bret4207

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JOB

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Butch(OH)

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Bret4207

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kevinstuff

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