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I Forge Iron

Slitter Geometry


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On 1/19/2018 at 11:49 PM, JHCC said:

Is this technically “upsetting”? To be sure, you’re hammering on the end of the bar, but that’s to open up the hole rather than to thicken the workpiece, yes?

Ain't t semantics wonderful... :)

Along with Judson's post, consider this as a definition for upsetting.

Upsetting will shorten your parent stock in length while increasing  the cross section of the parent stock at another chosen location.

I've wondered about this myself.

Also, until the advent of the internet and so many  beginner sites, I've always understood "slit and drift" implied actually slitting , upsetting the hole, and drifting to final size. Opposed to punching  and drifting  a hole. The former used when structural strength was required on the sides of the hole and the latter when thinning  the sides was not an issue.

Nor do I remember ever having  contemporary Smith's, before the net, or any old source books/pdf's being any different.

I did see this confusion happen after the net and so many beginners asking questions and misunderstanding just what "old school" slit and drift entailed. The new guys would do just that,,, slit, then drift and not upset. I then began to use all three terms when in these newbie groups.

I suspect the reason might be that before the net, our knowledge  still was passed down via smith to student either first hand or from old texts. The net changed all of this and "the expert" was the guy who watched the most YouTube vids! 

Thus the confusion. 

In my mind, there is only 3 ways to make a hole in iron.

Punched, slit and drifted, or drilled.

Thus, the op here is an interesting variation on a punched hole and only slitting and drifting is a combo variation of both. No material is removed via punching, yet to maintain bar length, thinning  of the sides must take place.

 Just my 2 cents mixed liberally with a bit of clinker...  ;)

 

  

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  • 5 months later...

Why cant I see any photos? I thought if I joined I would gain access but they are still dead links. 

Anvil - can you post a photo of your slitting tool profile? Also is there a good choice about what steel is hand forgeable and will hold its shape while hot ? I can goto metal supermarket to get most steel, but cant use power to forge.

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There was a forum software up/de grade that lost all of the older pictures; so if they were from a thread years ago they are in the bit bucket in the sky.  Recent ones should be visible.

Two steels liked by smiths for tooling that will be buried into hot steel (slitting chisels, punches) are H13 and S7  they can be hand worked but will be tough under the hammer.  They also support blacksmith means of heat treating.  Be wary of the proper forging temperatures!  I once cottage cheesed some H13 as I kept increasing the temperature hopping it would forge easier hotter.

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I will. I was going to post a pic a while ago, but forgot.

H-13 is a great hot work steel.

However I've used  coil springs, old flea market fasceted chisel, w-1,O-1, and they all work well. 

I harden and tempwr both ends of my hot work tools. Some do, some don't. It gives my tools far more time between dressing if I do, and let's face it. If you are here asking this question, practice heat treating prolly wouldn't hurt at all.  ;)

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  • 1 year later...

Slightly radiused cold chisel. By radiused look at an ax blade, the benefits of radiusing chisel edges has been discussed at length and will probably turn up with a search. 

How do you put the angle in the edge of a Brazeal style punch or slitting chisel? 

 Frosty The Lucky.

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I as wondering how DHarris profiled his slitter edge. This isn't about the edge bevels, it's about the edge profile. Are you familiar with a Brian Brazeal 120* slitter profile? Do you gauge the edge's profile angle or eyeball it? 

I forge close to finish and set the 120* edge profile in a corner of a hex swage, heat treat and grind the bevels. Brian Brazeal's punches carry the same angle. 

 Frosty The Lucky.

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You can’t see the profile well. I should have taken a picture prior to using it. I didn’t do a good job of hit, cool, hit, cool. It softened. 
 

To set the profile I placed two hex nuts edge to edge. I don’t have a welder at home and didn’t feel like driving the 60 miles or so to my Dad’s to use his. I just held them together with my fingers and used it as a gauge. I would file a bit and then see how far off it was and file again. The tip edge was just eyeballed to maybe 45.

This was a piece of tie rod. I plan to try again with coil spring. I’ve told the owner of Everything Welding & Safety he should consider stocking a few tool steel blanks. People like me who don’t like shopping online or driving into the city would happily pay two to three times market price just for the convenience. 
 

 

56CE1B2C-AC2E-4910-BE4A-7DF8C88D71F0.jpeg

7B04DFDD-FA12-43CA-A979-B4801893650A.jpeg

That was the very first time I ever punched a hole through anything. I got it off-center and slightly crooked, but I was happy with it. I was totally surprised it actually worked.  

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Welding two nuts edge to edge is the trick Brian recommended. A hex swage is the same angle and them I have. Keeping slitters from overheating is a chore but worth it. Using H-13 solves the issue though.

Frosty The Lucky.

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Some H-13 heat treatment procedures are frankly scary. However some make it sound only a little tricky. For thin tooling say 1" or smaller the soak time to allow the internal temp to equalize with the surface reduces to a couple minutes, The real trick would be the 30 minute soak at the target temp, 1,800f for max tough or 1,890f for max hardness. Under 5" thick can be air cooled in still air. The really complex processes are for complex and thick dies, not simple things like a punch or hot chisel.

A slitter or round punch? Starting in a cold forge, preheat to 1500-1600 f. and soak for a minute to make sure temps are equalized then up to 1,800-1,890F. soak for it's 30 minutes and place it on something that isn't a heat sink like a IFB to air cool.

I'm betting a preheated muffle to slip the punch into after equalizing at 1,500-1,600 f. would do nicely for holding austentizing the temp for 30 minutes.

Temper to 1,000-1150f. depending on "tough or hard" hold for 2 hrs. Back in a muffle wrapped in Kaowool or buried in perlite? 

I did't see ill consequences for tempering longer than the specified 2 hrs. 

Bear in mind I laid that out after spending a whole 5 minutes reading the first uncomplicated procedure schedule I ran across.

If you own or know someone with a ramping kiln it sounds more like a matter or programming. the above mentioned procedure is for MAXIMUM effect for industrial uses, most of us can do fine with less. 

Who here heat treats H-13 in their shop? Thomas?

Frosty The Lucky.

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Seemed weird to me too but I've read the heat treat schedule enough times to get over the shock. Now I'm wondering if "Metalsupermarket" in Anchorage has any 5/8" round to play with. 

Frosty The Lucky.

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I’ve got a real big chunk (2” round x 8”) Of H13 and access to power hammers, but I can’t seem to bring try forging anything from it. Lots of work even with a hammer and the heat treat sounds daunting, especially since the uses I keep coming up with would require a softer end for striking. I’m not ready yet.

David

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A lot of the high alloy steels sort of giggle when you hit them with a hammer. When I made my slitter, I hit it with a hammer---no noticeable deformation, hit it harder---the same; got a bigger hammer---small deformation. Decided to run the heat up to make it softer---blasted stuff started to cottage cheese on me!  I love my slitter; but it was a fight to get it.

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Yeah, according to the properties sheets, H-13 has a VERY narrow forging range and it's not recommended. 

So I should maybe buy strip stock and grind slitter and hot flat chisels. 

As annealed it has decent machinability. If I had a piece of 2" rnd I'd give a hot cut I've been thinking about a try. Saw a 1/4" disk and center drill it for a rod handle. Then sharpen about 1/3 of the radius as a hot chisel. 

This would PERHAPS make a hot chisel that I could hold and easily sight down the edge and roll along lines while striking. Sort of taking the curved chisel edge to the logical extreme.

I have plenty of leaf spring to prototype it and haven't gotten around to it. It just came to mind when I see Goods's crazy large for a home shop piece of H-13. 

I offer you the idea for a possible use Goods. No guarantee it's just an idea that's been rattling around my head for a while.

Frosty The Lucky.

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I have a few hand tools from H 13. I made them at Turley forge and cannot find my notes.

Perhaps if he sees this he will reply.

So

I believe we simplified the process and did not anneal. This is the only complex step in the process. Lol, since I normally anneal, I will call this the exception that makes the rule.

My slitter has held up fine for years. It's one fault, and this could be due to not annealing, is that if you cut thru your hot iron and hit your mild steel cut off plate, you will have to dress the edge. It will upset like butter! If you don't allow this to happen, literally you will rarely have to dress the edge.

Here's the specs from the heat treaters guide, and I'm pretty sure it's the process I learned long ago.

Forge: forge from 2245f and not below ~ 1600f

Normalize: 1650f and cool in air

Harden: 1580f and quench in oil

Temper: temper to desired hardness.

I can't remember if we tempered or not. However if I made hand tools now from H13, I would polish the edge and draw the temper to a light straw for starters. I would use the reserve heat technique, meaning quench the tip then let the colors run.

We did not use any HT equipment, all was done by recognising colors 

I believe it is critical to not go above forging temp and the cooler it gets the harder it is to forge.

Works for me.

 

 

 

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From the sites I looked at the finicky heat treatment schedules are for thick or complex shapes, one site calls 5"+ thick sections.

1,580 might have been too cool. All the specs I've seen call for 1,800 for tough and 1,890 for hard. 

Eyeball info is good. Thanks.

Frosty The Lucky.

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Frank Turley won't be replying; He was in a wheelchair when they held the ABANA Heritage Award presentation at the Turley Forge and not doing too well.  From the Turleyforge website: "NOTICE In 2019 and 2020 a Turley-trained journeyman, will be conducting classes. Frank Turley will be semi-retired, but will occasionally be on hand in the shop, if need be."

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