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SirLesPatterson
03-01-2015, 09:05 AM
Before I got into machining a local hardware store had sorted out all of their old fasteners from a previous vendor and put $1/box on them. Living in the sticks I have always like to have hardware on hand so I asked them how much for all and I think I ended up giving $40 or $50 for the lot and ended with about 75+ lbs of brass and steel. It's in labeled retail boxes, which is a welcome change from my buckets of random bolts. It has definitely paid for itself out of time savings since any store is an hours round trip.

Anyhow, I finally got to organizing my fasteners today and the though popped up that I should learn when it is appropriate to use brass vs. steel? I've got a little over 25 lbs of brass machine screws here. The widgets I make are usually aluminum or steel, mystery alloys. Are brass screws strong or weak? So far I've been using them just to hold things together that don't have much strain on them, mostly because I like the way they look. Is there a rule of thumb?

Thanks.

Carm
03-01-2015, 09:21 AM
"Are brass screws strong or weak? "

Can't really answer that.
Generally speaking, hardware store stock is soft brass and lacks tensile strength. Any internal drive except allen is easily stripped before exceeding the yield.
There are copper alloy fasteners approaching steel strengths, but not found in the local...maybe several decades ago.
Sometimes you need to consider galvanic couple and/or service environment. If you have ever had to repair a valve washer in acidic water service you know what I mean.

loose nut
03-01-2015, 12:59 PM
In the "old" days things where more frequently made out of brass instead of the brass plated jello we get know, hence the need for brass screws for repairs excreta, so hardware stores used to stock brass screws. Brass on brass, steel on steel.

Black_Moons
03-01-2015, 01:10 PM
In the "old" days things where more frequently made out of brass instead of the brass plated jello we get know, hence the need for brass screws for repairs excreta, so hardware stores used to stock brass screws. Brass on brass, steel on steel.

Yep, To be used on brass would be about the only place I would use them. Or for a low strength fastener somewhere cosmetic.

Rosco-P
03-01-2015, 02:02 PM
If you want something stronger than brass you'd switch to Silicon Bronze screws. Not cheap by any means.

For more info, skim through this document: http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

Black_Moons
03-01-2015, 02:56 PM
If you want something stronger than brass you'd switch to Silicon Bronze screws. Not cheap by an means.

For more info, skim through this document: http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

Non sparking screws.. For people who can't seem to use screwdrivers properly.

SirLesPatterson
03-01-2015, 02:56 PM
Ok, thanks for the info. Good to know.

Mike Burch
03-01-2015, 03:19 PM
Don't use them where sea-water can get at them. It will strip out the zinc, leaving only amorphous copper with little if any strength.

peekaboobus
03-01-2015, 03:33 PM
When you don't want them to be attracted to the magnet or magnet onto it.

You can also choose plastic screws in those cases but obviously brass is a lot stronger and tougher than plastics of the same size.