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audrey
11-26-2002, 06:48 PM
I am attempting to build a V-Block from A-2 Material. Any hints or tips guys in making this thing would be greatly appreciated. Also any milling tips on cutting(flycutting) S/S 304? Thanx Guys

crypto
11-27-2002, 01:36 AM
Audrey,

Oh yes, stop right now. Toss the A-2 as far as you can throw it and start all over again with a nice friendly piece of 1018 or similar which can be case hardened. A-2 vee blocks are for penitents or masochists.

Paul Gauthier
11-27-2002, 06:40 AM
Crypto"

Well said and very true.

------------------
Paul G.

crypto
11-27-2002, 11:49 AM
Hi,

'tis me again. I didn't want to sound flippant in contributing to your query. It's just that the mere thought of using a steel as tough as A-2 to make vee-blocks or any other tool that does not require its toughness and hardness is rather chilling to any experienced machinist.

What that stuff does to cutting tools is rather unpleasant to contemplate.

Tell you what, look up some machine shops in your area, just knock on their door or walk in the open shop and explain what you are attempting to do and ask them if they could be kind enough to sell you a piece of steel that would not be too tough for someone to machine into vee-blocks.

The intent, of course is to get a free piece of scrap that might be just perfect for your project.

If you find a friendly and supportive shop then when you have finished the project return and show it to them with your thanks and a bag of donuts. I'm not joking about the donuts! And after receiving their praise and thanks, ask for help in having the blocks heat treated.

Don't be bashful about asking for help, as you can surmise from scanning this website MACHINISTS LOVE TO TALK ABOUT THE TRADE.

304 should not be any trouble to machine. The Carpenter stainless steel book suggests a cutting speed or SFPM of 85 to 100 and a feed rate at .050" .001-.004" per revolution of cutter.. I quote "The alloy machines with chip characteristics midway between those of conventional Types 304 (this is a reference to their Project 70 SStype 304) and 303. Although chips are not as stringy as those of conventional Type 304, the use of chip curlers or chip breakers is still advisable. Since austenitic stainless steels work harden rapidly, heavy positive feeds should used.

Good luck,

Oscar Ortiz      

Thrud
11-27-2002, 11:58 AM
Trust the ever wise Oscar - Doughnuts!

It is a terrible waste of A-2 anyway - fantastic for plane blades, wood chisels. knives. Too expensive for casual use as a V-block. 4130 or 4140 would be cheaper and easier to machine.

If you are a real massochist make one from D-2. http://bbs.homeshopmachinist.net//eek.gif

[This message has been edited by Thrud (edited 11-27-2002).]

crypto
11-27-2002, 12:00 PM
The .050" refers to the depth of cut. The reference to "heavy, positive cut" means do not allow your cutter to dwell or merely rub on a freshly made cut. The material will work harden itself from the friction of the rubbing and its structure will become harder (it will develop what we call a "hard spot" )and consequently become harder to cut. This condition is especially nasty to encounter when drilling a deep hole in the material.

This brings to mind the importance of KEEPING THE TOOLS SHARP-----A DULL TOOL WILL CREATE A "HARD SPOT".

L Webb
11-27-2002, 06:54 PM
Make it out of A2 if that is what you have. We machine this stuff all day long and there is nothing wrong with it. When I need to make a handle or simple shaft or any small part I usually grab some A2 as I have tons of it around and I get it cheap.
You'll quickly find out if you're using the wrong tool or feeds to cut the A2 as the finish will be terrible. Get it right and it comes out nice.
Les

BrianH
11-27-2002, 10:35 PM
We've covered "don't use A2" pretty good, so
on to your second question....

304 is pure **** to machine. Avoid it if you can...If you can't,

-Use carbide, run it slow, keep your cuts light and cool; 304 generates tons of heat, and flycutters just won't hold up. Main thing is to keep it going slow, and keep it wet. If you are using a lathe bit flycutter, get a carbide bit.

Be a little more specific about what you're doing, and we can give more specific answers.

BTW....if you don't plan on grinding your V-blocks, I wouldn't even bother heat treating.
With a little practice, you can get pretty good at hardening 4140 in oil with an oxy torch. But heat treating without grinding is kind of like paint on a dog turd....

JWL
11-28-2002, 11:43 PM
I don't understand all the anti-A2 commentary. It machines well and can be treated to about any reasonable level of hardness or toughness. It is also inappropriate to consider grinding a neccessity on all treated A-2 projects. I say go for it. Make a vee-block that will last a lifetime, and have fun doing it.

Thrud
11-29-2002, 01:37 AM
BrianH:
If you machine any stainless it is a good rule of thumb to insure you never make cuts of less that about .oo3".
You have to get under the work hardened surface to cut well.
316L cuts nicely, avoid 304 it work hardens the worst, use 303 for medical stuff.
T-15, or M-42 have high heat hardness and work well. Sharp carbide works best.

My only nay-saying on A-2 is it is better suited to cutting tools.

[This message has been edited by Thrud (edited 11-29-2002).]

audrey
11-29-2002, 10:15 PM
<font face="Verdana, Arial" size="2">Originally posted by Thrud:
BrianH:
If you machine any stainless it is a good rule of thumb to insure you never make cuts of less that about .oo3".
You have to get under the work hardened surface to cut well.
316L cuts nicely, avoid 304 it work hardens the worst, use 303 for medical stuff.
T-15, or M-42 have high heat hardness and work well. Sharp carbide works best.

My only nay-saying on A-2 is it is better suited to cutting tools.

[This message has been edited by Thrud (edited 11-29-2002).]</font>
Wow Guys I sure got a lot of differant einformation. I just plogged away and this V-Block is actually a part of a Die Set I am trying to build. It is my first one and a simple(Or so certain people say) Shearing Die Fuor One and a half inch by .125 thick aluminumn angle material. I appreciate all the comments. Thanx Audrey

BrianH
11-29-2002, 10:46 PM
I guess I responded that way because I just got done running 5 parts out of about 20 lbs. of 304. I agree, if you can use 303, it's the best way to go. I don't really have a choice; I make parts out of what the engineers want, and they seem to be on a 304/440/17-4 kick these days. Prob. because the parts get exposed to a lot of printer ink, which is pretty corrosive. Anyway,

A trick we all use in the shop to ruff materials like stainless that works pretty good is to take a 3/8 to 1/2" or so 4 flute (this is good for one with slightly cooked corners), take it to the grinder and put 45's on all the corners, about 1/8" or so; take a cut about .025" deep, feed about 30ipm at about 4-500 rpm. Rips through it surprisingly fast, and when you burn up your edge, just go touch up the 45. Works great.

L Webb
11-30-2002, 10:12 AM
Audrey, you made a good choice on material for your shear die. Had you stated what the v-block was for it would have helped many with their responses.
Are you going to have the heat treating done or do it yourself?
Les