I am thinking of making a hot punch and slitter and was wondering if that requires high carbon or tool steel, or whether I could get by making them from mild steel. I figure hardening and tempering would be useless, as the hot metal would ruin a heat treat, but, if I'm not mistaken, high carbon tends to be more resilient than mild, even unhardened, so I'm not sure what to do with this.

Thanks!

Scruffy

Well one thing would be to review what was posted all those other times this has been discussed here.

Steels with medium to higher carbon content are stiffer than mild and less likely to upset in the hole.  Even better are the high alloy steels like H-13 or S-7 which stay hard when hot---drawing temp is in the *glowing range for some steels!

For beginners we often suggest automotive coil spring---often 5160 and cheap, easy to source, work and heat treat, (I'd suggest normalization)

7 hours ago, ThomasPowers said:

For beginners we often suggest automotive coil spring---often 5160 and cheap, easy to source, work and heat treat, (I'd suggest normalization)

Such punches (especially in smaller sizes) can easily overheat and deform if not cooled regularly and repeatedly during punching. This is actually a benefit, since it reinforces good punching technique by giving instant feedback on bad.

giving feedback means they may get trapped in the hole and require damaging efforts to remove them,,,,

Ayup, peining the punch in the hole, turning it into a tenon is good training and a better reason to use steel that's inexpensive, easy to source and work. It's also a good exercise figuring out how to get them apart, rework the tool, etc. Finding or making a good punch lube is another benefit that'll last a lifetime.

I keep a  range old coil springs for punches, drifts, etc. 

Frosty The Lucky.

14 minutes ago, Frosty said:

I keep a  range old coil springs for punches, drifts, etc. 

If only someone would come up with a simple, effective way to straighten heavy coil spring!

the above is sound advice! yet , there is merit in  buying expensive tool steel and doing it wrong! as it's a lesson well remembered.

to the OP , many a smith with oodles of experience uses coil spring for drifts(and not just because we're cheap )  

I find a long cheater pipe slipped over the end works better than bending forks and a torch is a lot better than trying to fit it in a forge. If you don't mind the scarring large pipe wrenches work well enough.

Of course ideally you have a good anchor point and a vehicle powerful enough to pull it. Heat the whole spring, drop it over the anchor and pull it straight with the pickup truck, tractor, etc. Have you ever seen how far you have to drive to uncoil an overhead door spring?

Frosty The Lucky.

The easiest way is to measure off the length you need on the coil and cut the short piece off... angle grinder, hack saw, etc. The short piece is much easier to straighten and shape.

7 minutes ago, Frosty said:

I .

Of course ideally you have a good anchor point and a vehicle powerful enough to pull it. Heat the whole spring, drop it over the anchor and pull it straight with the pickup truck, tractor, etc. Have you ever seen how far you have to drive to uncoil an overhead door spring?

Frosty The Lucky.

I have a supplier that will give me a complete clutch kit for my Ford Ranger for less than $50 and I have guys on the payroll who could fit it quite inexpensively yet I don't use my veichles in this fasion {odd I know} maybe I should give it a bash with the mini digger or a skid steer.

Tales all the fun out of dragging a workbench by the postvise attached to it with 8' of red hot steel being pulled by your truck....

Though this month's winner of the "Paging Darwin, Paging Darwin, Darwin to the smithy, STAT!" award must go to the "heating up 200 pounds of steel to over 1500 degF and placing in a 55 gallon drum of oil" suggestion.  Thankfully it was just a suggestion  made not intending to be realized!  The possibilities of a fuel air explosion with it seemed great to me...

4 minutes ago, ThomasPowers said:

Tales all the fun out of dragging a workbench by the postvise attached to it with 8' of red hot steel being pulled by your truck....

Thomas should I send you a link on "how to make tent (read workbench) pegs"?

16 minutes ago, ThomasPowers said:

Thankfully it was just a suggestion  made not intending to be realized!

No, there are videos on youtube.

30 minutes ago, Frosty said:

Have you ever seen how far you have to drive to uncoil an overhead door spring?

Yes, but I've done it with a pair of tongs and some good running shoes.

3 hours ago, Frosty said:

Finding or making a good punch lube is another benefit that'll last a lifetime.

I keep a  range old coil springs for punches, drifts, etc. 

Frosty The Lucky.

I've heard that coal dust can be used as punch lube. Is that correct?

Scruffy

There are a lot of good IFI discussions of punch lube, SLNH. Coal dust is one option.

Yeah, I don't use coal much so I don't have a lot of experience with coal dust as a punch lube. I quench mine then give it a touch to the bee's wax every 2-3 blows. I've used lithium grease and have some graphite powder I haven't tried. The grease works pretty well.  On the other hand one of our guys recently located a seam of good smithing coal so I may get some practice.

I believe being quick makes more difference than lube. 2-3 blows and GET IT OUT! 

Tossing the stock back in the forge while cooling and lubing the tool helps keep it at an optimum temperature.

Frosty The Lucky.

The problem being that once you get your rhythm set: Whomp, Whomp, Quench; it makes it hard when you switch to a high alloy steel that DOES NOT GET QUENCHED

 

2 minutes ago, ThomasPowers said:

The problem being that once you get your rhythm set: Whomp, Whomp, Quench; it makes it hard when you switch to a high alloy steel that DOES NOT GET QUENCHED

 

Uh huh. adapting to new things is part of the game. Think of it as evolution in action. Adapt or die.

Happily it's only a tool or project that dies. Hopefully! 

Frosty The Lucky.

I found adapting to the high alloy punches and chisels easy; it's when you go backwards that the "oops" tend to occur...I like "knife blade slim" H-13 slitting chisels!