Thread: WTB 304 stainless discs 59mm dia minimum

There is a guy at the Laverton Markets most Saturdays who has all sorts of off-cuts, steel, stainless steel, aluminium and brass. He may have something.

Does it have to be Stainless Steel, wouldn't 6061 Aluminium do the job just as well?

If you are concerned about machinability, 303 is a lot easier to machine than 304.

Interlloy -303 Stainless Steel Bar - Interlloy

Originally Posted by Big Shed

There is a guy at the Laverton Markets most Saturdays who has all sorts of off-cuts, steel, stainless steel, aluminium and brass. He may have something.

Does it have to be Stainless Steel, wouldn't 6061 Aluminium do the job just as well?

If you are concerned about machinability, 303 is a lot easier to machine than 304.

Interlloy -303 Stainless Steel Bar - Interlloy

Laverton is a bit far away unfortunately but thanks for the tip. Offcuts galore has a 200mm length of stainless but he doesn't know what grade it is and I dont fancy spending 30mins with a hacksaw to cut off a disc.

Ive thought of using ally, but in use they tend to get knocked around a bit i so I think ally will end up getting marked, oxidise etc. Theres a reason why all of the commercially available tampers are made from stainless.

303, 304 either one would be suitable. I only have a minilathe, so the easier to machine the better.


[ame="http://www.youtube.com/watch?v=DWe1sJ0GaIc"]YouTube- how to use the coffee tamper 'eazytamp' at bay coffee roasters[/ame]

I would say the reason the commercial ones are made from stainless is that they will have to go in a dishwasher etc, rather than mechanical properties.

You should be able to get 303 bar in a suitable diameter from Interlloy (see my link above) they are in Dandenong and to the best of my knowledge they cut to size.

304 (and I suspect 303) is very prone to discolouration in mildly adverse environments, so not reccommended for exterior use in coastal areas etc if user will expect it to retain its original finish. I suspect that it would discolour fairly quickly as a coffee tamper. 316 or a food grade may be a better option. Also 304 is a fair dog to machine as it work hardens and can have hard spots in it. Getting a good finish on a mini lathe may not be easy, but should be possible if you take it to a metal polisher for finishing.

Originally Posted by malb

304 (and I suspect 303) is very prone to discolouration in mildly adverse environments, so not reccommended for exterior use in coastal areas etc if user will expect it to retain its original finish. I suspect that it would discolour fairly quickly as a coffee tamper. 316 or a food grade may be a better option. Also 304 is a fair dog to machine as it work hardens and can have hard spots in it. Getting a good finish on a mini lathe may not be easy, but should be possible if you take it to a metal polisher for finishing.

http://www.coffeetamper.com.au/products/deluxe.html

this guy uses both 304 and 316, so I dont think 304 would be a problem. They never get washed in a dishwasher or anything like that as they dont ever really get dirty. All they ever come in contact with is ground coffee and I guess some of its oils.

Is 304 much harder to machine than O1 steel that's not been heat treated?

I used 316, and it was ok to machine, takes a mirror polish if so inclined as you say ali won't stand up to the task, just for my own interest are you going to make a domed base or a flat base.

Originally Posted by China

I used 316, and it was ok to machine, takes a mirror polish if so inclined as you say ali won't stand up to the task, just for my own interest are you going to make a domed base or a flat base.

aha, a coffeesnob also hey?

I would probably start off with a flat base. I havent rigged up a powered cross slide yet so getting a nice even finished on a curved surface would be tricky.

I have worked with mirror polished stainless (shopfitting fixtures, think Prada) and it is a beautiful finish.

Would brass or bronze work?

Pete

Originally Posted by QC Inspector

Would brass or bronze work?

Pete

yes brass or bronze would work, but its a matter of how long it could hold the flawless appearance. Not much can match the durable qualities of stainless steel.

Martrix, Just so you know I have gone with a flat base, much better than the domed one I used to use

Originally Posted by martrix

yes brass or bronze would work, but its a matter of how long it could hold the flawless appearance. Not much can match the durable qualities of stainless steel.

True, but they are a lot easier to machine with a small lathe.
If you were in my neighbourhood I'd give you a piece of titanium scrap from work. If you managed to make the tamper from it, you would have your match for the SS.

Pete

martrix, I have a circular dropout of 25mm 304 SS plate that's about 78mm in diameter.
It was cut with a waterjet and weighs 952g.

If it's too big for your chuck, I can turn a step on it down to a suitable size (for the right price).

If it's what you're after, make me an offer (PM is fine).

Postage would be $9.90 or $11.30 for overnight.

To give you an idea for a price, the website below pays $1.20 kg for scrap stainless steel solids. Most places usually double it when selling to the public.
Evelyn Recycling | Cash for Scrap
Dave

Originally Posted by 60,000psi

martrix, I have a circular dropout of 25mm 304 SS plate that's about 78mm in diameter.
It was cut with a waterjet and weighs 952g.

If it's too big for your chuck, I can turn a step on it down to a suitable size (for the right price).

If it's what you're after, make me an offer (PM is fine).

Postage would be $9.90 or $11.30 for overnight.

cheers, that might be an option. I will check out my chuck to see if it can take 78mm.