temper vs RC hardness

[SR_matt]

hello all,

been away for a while and really have dropped off making knives but im going to school for jewelry and glass working and in the last few weeks ive really gotten interested in tool making for glass working (hot working such as glass blowing). there are no tool makers in VA and very few on the east coast so i expect there would be a market if i can figure out good designs and produce quality tools.

no here comes my question, some of the tool makers list metals and temper of the steels they use but like one i saw it is referred to as "half hard spring steel" (iirc this is on 304 stainless). what the heck RC is that equivalent to and/or how would i go about getting that in the steel.

also does any one know what the corresponding RCs are for dead soft all the way up to full hard on 304 and/or D2 (these are the 2 most common steels ive found are used on the glass tools).

thanks for any help, i know this is not exactly "knives" but it is an item that is used to cut and i figure i could find my answers here
-matt

 

[george tichbourne]

For glass working tools 304 is a common choice because it has some spring capacity as it is supplied from the rolling mill and also is a poor conductor of heat.

As rolled, the 304 is used in some cases as light duty springs though the spring capability can be enhanced by cold working the steel.

The poor heat transmission of 304 allows it to be used as a blow pipe for glass without the heat being transferred along the length of the tube to the glass blower's lips. I have polished many for a local glass blower's supplier.

George

 

[mete]

Here's data for 302 ; Full hard - 40-45 HRc
3/4 - 35-40
1/2 30-35
1/4 25-30
From www.precisionsteel.com Each steel is a little different.You would have to buy sheets or wire to that temper as these alloys can't be hardened by heat treating , only by working either cold rolling or wire drawing.

 

[SR_matt]

Here's data for 302 ; Full hard - 40-45 HRc
3/4 - 35-40
1/2 30-35
1/4 25-30
From www.precisionsteel.com Each steel is a little different.You would have to buy sheets or wire to that temper as these alloys can't be hardened by heat treating , only by working either cold rolling or wire drawing.

thanks mete i was hoping you would respond.

im not sure if you would really have a whole lot of insight in this but would 304 be the best choice (that seems to be the grade of choice of the tool makers but im not sure if its just the best price/performance balance) the metal gets exposed to 1000-2000* f a lot, not for extremely long times but at least 30 seconds at a time 1000s upon 1000s of times over the life of the tool (heck i know a lot of people that have tools that are 60+ years old all the time)

i think i am going to try and get a pair of diamond shears done up in dec when i am on winter break (examples are the 1st and 5th if any one is interested https://www.keysecure.com/cuttingedgeprdx.com/cgi-t/cart.cgi?cart=Shopperdude&category=Shears ). those are used to grab the rods (punties) and pipes when you add bits of glass or transfer pieces etc and then used to cut hot glass. the shears are the d2 so it shouldnt be to hard to do (im going to get them water jet cut with the handles attached so i dont have to beg a friend to weld them for now) so all i have to do is grind the blades, round the grips and dip them in plasti-dip and toss a bolt and nut on them.

thanks
-matt