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CCWKen
11-03-2007, 02:31 AM
I need to make a quick punch and die for a one-off rectangular hole. (actually a pair) I thought about using some old HSS tool bits and weld up the die and tack-weld a another bit sideways to round stock for the punch. If I heat the tool bits up to cherry red then weld, do you think they'll stay together?

The hole needs to be 3/8 x 1".

Thanks, Ken

Update: Corrected hole measurement

Norman Atkinson
11-03-2007, 05:15 AM
It has been accepted practice to 'silver solder' - you call it 'silver braze' HSS bits to parent ordinary steels. Looking back, I recall that there was silver solder foil made expressly for that purpose.

Welding- if that is what you mean- I would doubt. You would be mixing the two alloys and probably losing the properties of both. Oxy acety??? You makker der joke, eh?

I would add that moving onto to car body welding of high strength low alloy steels, you would be sticking you neck out with oxy- and with a MigMag set have to know exactly what you were doing.

Cheers

Norman

Timleech
11-03-2007, 05:23 AM
I've welded HSS toolbits to mild steel and EN8 (1040 in US-speak?) to make up slotting tools, more than once, using 316 stainless electrodes with no preheating. I don't know how they would stand up to many hours of continuous work, but they've survived the jobs I've made them for with no sign of any cracking.

Tim

Your Old Dog
11-03-2007, 07:57 AM
I recall that there was silver solder foil made expressly for that purpose.

I'm likely telling you something you already know Ken but don't forget you can clean off the anvil of your vice and the face of a hammer and make your own sheet from the round braze wire you have by annealing it first. Just whomp it to whatever shape you want :D

oldtiffie
11-03-2007, 08:10 AM
I'm likely telling you something you already know Ken but don't forget you can clean off the anvil of your vice and the face of a hammer and make your own sheet from the round braze wire you have by annealing it first. Just whomp it to whatever shape you want :D

Seems reasonable to me YOD.

Silver-soldering/brazing is more than good enough to hold TC tips to steel tool bodies.

I can also see SS electrodes as advised by Timleech working as well. I've had some goods success with MIG.

The "male/punch" will be OK for later forming or grinding.

I'd suspect/expect that the "female/die" parts would need to be surface ground for the edges and reliefs before welding/fastening and finished after welding.

I hope some more with punch and die experience will take up this thread as well.

DR
11-03-2007, 09:20 AM
I've welded a number of HSS tool bits for special lathe applications. TIG with no filler, just a fusion weld. No preheat, but some of the welds crack, then I re-weld, the welding heat acts as preheat.

For only punching a couple holes the punch/die material isn't critical. In an extreme case an old socket and extension would work to do a 3/8" square, punch another hole next to it and you've got 3/8 x 3/4".

Even mild steel with a light case works well.

lazlo
11-03-2007, 09:25 AM
I thought about using some old HSS tool bits and weld up the die and tack-weld a another bit sideways to round stock for the punch.

HSS tool bits are heat treated. If you weld it, you run the risk of losing the temper on the tool, especially if it's a small bit.

Basically, if the HSS tool bit gets discolored (rainbow colors) from the weld, it's lost its temper...

rkepler
11-03-2007, 12:40 PM
HSS tool bits are heat treated. If you weld it, you run the risk of losing the temper on the tool, especially if it's a small bit.

Basically, if the HSS tool bit gets discolored (rainbow colors) from the weld, it's lost its temper...

I think that you have that exactly backwards. A high carbon steel will likely have lost its hardness when you have surface colors (the temper will certainly have changed) but a HSS will not change much at all. I've welded HSS toolbits together and used them as-in afterwards with no effects from the welding.

To anneal HSS you usually have to take it up to something like 2200 degF + and cool it at some really slow rate, 50 degF/hr or so. It's made to cut at a dull red without too much loss in hardness, and that loss is regained on cooling. For the most part a HSS isn't really quenched as much as "allowed/encouraged to cool rapidly", using in what we would normally consider a hot oil.

The one thing you want to be careful about with HSS is in grinding. If you get the edge really hot and dunk it in water the rapid quench can cause microcracking. You won't notice it until using the tool and you get some cratering behind and on the edge.

lazlo
11-03-2007, 08:40 PM
Hi Russ,


I think that you have that exactly backwards.

I've welded HSS toolbits together and used them as-in afterwards with no effects from the welding.

To anneal HSS you usually have to take it up to something like 2200 degF + and cool it at some really slow rate, 50 degF/hr or so.

If you look at the M2 datasheets, the critical temperature (when the steel changes its structure to austenite) is 1500F, and the annealing temperature is 1600F:

http://www.crucibleservice.com/eselector/prodbyapp/highspeed/rexm2sh.html

Steel melts between 1350 and 1500 F, and the TIG tip temperature is considerably higher than that, so the HSS in the heat affected zone should be well within the annealing temperature.

Cheers,

Robert

oldtiffie
11-03-2007, 09:37 PM
I'd like some advice on what works for people in the situations that they have used it - perhaps similar to the situation described in the original post on this thread?

I do not envisage a "production" environment where work speed, coolant, and tool life etc. are critical - just enough to get a small job done.

It should be just something that "worked for you" and "got the job done" in a small jobbing shop or HSM shop.

What did you need done?

What did you do?

Why did you do it as you did?

Was it a sucess?

If so - why?

If not - why?

Were there "other ways"?

etc. etc.

lane
11-03-2007, 09:37 PM
Been welding tool bits for years. HSS to CRS are what ever make fly cutters boring bars any kind of tool I need . USE stainless steel or nickle welding rods Will not take temper out of. tool bit Some people on this site read too many books and wont try things because of it . Their are No books in the machine shop on the Job. Just get the D-M job done.

lane
11-03-2007, 09:39 PM
Been welding tool bits for years. HSS to CRS are what ever make fly cutters boring bars any kind of tool I need . USE stainless steel or nickel welding rods Will not take temper out of. tool bit Some people on this site read too many books and wont try things because of it . Their are No books in the machine shop on the Job. Just get the D-M job done.High speed tool bits will hold their hardness at a RED heat. Sorry messed up Double post.

oldtiffie
11-03-2007, 10:07 PM
Thanks Lane.

That - as usual - is exactly what I asked for.

I either MIG weld or silver solder or braze tool bits onto fly-cutters and boring bars and "other stuff" as required and just sharpen or replace as required.

I've had no trouble bending, forming or forging HSS to the the extent that it won't work if I'm careful and take my time.

May not suit a "full on" production shop but that is not what I've got nor is it what I need or want either.

I am in a HSM environment where I take my time. HSS is the norm here and TC is the method of last resort.

If my machines are groaning or complaining and if I've got "stinking hot blue chips" coming off, I've got it wrong and need to stop, take stock and do things better.

This is my "hobby" shop that I use for "hobby" stuff - no more - no less.

I work on the basis of "I fu*k it - I fix it". And the less "F-n-F" the better!!

I suspect that I am not alone.

CCWKen
11-03-2007, 10:48 PM
LOL... Yeah, them books and rules sure can put the kabosh on a good idea. :D Sorry not to get back sooner but I was making the forming dies for the part that will have the rectangle hole. It's a simple part to a 1926 Closed Cab TT but no one in the World makes the sheet metal part(s). I only need two and it's holding me up. I'd either have to go without or put the old rusted out pieces back onto new panels. (Also which no one makes.)

If I were to make a slew of these, I'd make a progressive die to stamp the shape, the hole and cut to final size in one cycle. As it were, I had to experiment with the stamping (press) die to get the correct size and shape. I got the two pieces made and started on the punch die today. I'll try and post some pictures tomorrow.

Thanks for all the ideas and encouragement.

rkepler
11-03-2007, 10:51 PM
If you look at the M2 datasheets, the critical temperature (when the steel changes its structure to austenite) is 1500F, and the annealing temperature is 1600F:

http://www.crucibleservice.com/eselector/prodbyapp/highspeed/rexm2sh.html

Steel melts between 1350 and 1500 F, and the TIG tip temperature is considerably higher than that, so the HSS in the heat affected zone should be well within the annealing temperature.

Cheers,

Robert

Steel does not melt at 1350 to 1500, you're confusing the melting point with the critical point. I managed to confuse the hardening temp with the annealing temp (which are generally the same in a high carbon steel) but the hardening temp listed for M2 on your reference is 2200 degF.

The point remains - what hardens a steel (that can be hardened) is the rate of cooling. Some simple steels can be heated and left in still air and they will be annealed, more complex alloys will harden in the same conditions. HSS, unless cooled *very* slowly, will harden. You can heat that HSS to a nice orange and let it cool on a rack and it'll be almost as hard as it was when you got it even though it went above the annealing temperature and passed through it on the way back down. Heat the same piece of steel the th4e same temperature and let it down slowly in an oven and you'll have a nicely annealed piece of HSS when you're done.

wierdscience
11-03-2007, 11:11 PM
We had a company in town that made custom electrical connectors and brackety for the electronics industry.All of thier punch tooling was made up of ground to size HSS toolbits that were laid up in stacks and welded together around the sides and accross the bottom.Nothing fancy,just 7018.A heated pile of sand was used to cool them off slowly.

When welded you end up with a transitional area that runs from 67-70rc at the tools cutting edge,down to 58-60 in the weld area and then down to the base metal the bit is welded to.

I have made offsetting dies out of 1x1x6" HSS toolbits and those where seal welded all the way around the perimeter with a 3/8" fillet.The top of the face was perfectly hard as before when ground to dimension.

CCWKen
11-03-2007, 11:20 PM
Well, I did find this picture of the original part. I made a new seat side panel and the part I'm stamping is the small "hat" shape in the corner of the panel. It holds a rubber bumper for the door so it's a must have. It also needs to be "correct".

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/SeatSidePanel-Old.jpg

lazlo
11-03-2007, 11:58 PM
Steel does not melt at 1350 to 1500, you're confusing the melting point with the critical point.

Sorry Russ, I meant 1350C -- the melting temperature is obviously higher than the annealing temperature :)
The critical temperature and annealing temperatures I quoted, of 1500F, and 1600F, respectively, are in Farenheit, and directly off the CPM datasheet.


The point remains - what hardens a steel (that can be hardened) is the rate of cooling.

Yes, but the critical temperature of 1500F is the austentizing temperature (when the iron is going back into solution), and you're surely hitting the prescribed annealing temperature of 1600F.


Been welding tool bits for years.
...
High speed tool bits will hold their hardness at a RED heat.

Lane, the red hardness of M2 HSS is 1,000. In other words, the hardness drops from greatly from ~ 67 Rockwell (at room temperature) above 1,000
I'd be willing to bet a round of beer that you lost a lot of hardness from those tools after welding them.


Their are No books in the machine shop on the Job.

Durn that Machinery's Handbook! They wrote 1400 pages for nothing! :D

lazlo
11-03-2007, 11:59 PM
All of thier punch tooling was made up of ground to size HSS toolbits that were laid up in stacks and welded together around the sides and accross the bottom.Nothing fancy,just 7018.A heated pile of sand was used to cool them off slowly.

When welded you end up with a transitional area that runs from 67-70rc at the tools cutting edge,down to 58-60 in the weld area and then down to the base metal the bit is welded to.

Thanks Wierd -- that's exactly what I would expect based on the HSS datasheet. So you're losing 10 point of Rockwell hardness in the heat affected zone, even if you cool it slowly, as I suggested in my original post.

lane
11-04-2007, 12:03 AM
They cut the same as regular ones . And held up as good . Try it out.

lazlo
11-04-2007, 12:08 AM
I believe you Lane -- although like I said on the first page, I'd want to have enough HSS to keep the cutting edge as far away from the heat affected zone (the area surrounding the weld that's distorted by heat for the non-welding readers).

The smaller the HSS piece you're welding, the closer the cutting edge will be to the HAZ, and the more hardness you'll lose. In theory :D

Seriously, I'll TIG weld a couple of lathe tools this week just for fun. I don't have a hardness tester, but you should be able to notice a 10 point loss in Rockwell hardness on normal turning (I think?).

Lane, when you weld yours, do you cool them in sand or vermiculite to slow it down?

rkepler
11-04-2007, 12:36 AM
Yes, but the critical temperature of 1500F is the austentizing temperature (when the iron is going back into solution), and you're surely hitting the prescribed annealing temperature of 1600F.

With a hardening temperature of 2200 degF don't you think that *any* quench is going to pass through that temperature on the way back to room temp? I think you're missing the point: it takes slow cooling to anneal, fast cooling to harden. It you weld that HSS where the mass of the body will quench it, or toss it on an anvil to cool it'll be plenty hard to cut afterwards. It might lose a few points of hardness over a proper heat treat but it certainly not going to anneal. Really, it's hard to *anneal* HSS.

Back on the original question - I've silver brazed A2 to steel shanks to make form cutters. It always cools well enough in air to be plenty hard. I'm sure that proper heat treat would give a better tool, but it was fine for the purpose. Carbide, of course, won't lose anything by being brazed to a steel shank. It's a bit harder to wet with the braze, black flux worked better for me than white.

lazlo
11-04-2007, 12:54 AM
With a hardening temperature of 2200 degF don't you think that *any* quench is going to pass through that temperature on the way back to room temp?

Oh, so you're saying that the welding process will anneal-out the hardness of the HSS, but if you quench it quickly, you can temper the HSS?

The problem that I see with that is heat treating HSS is a pain in the butt -- it's more complicated than heating O-1 to red and quenching in oil.

This is CPM's recommendations for heat treating annealed M2:

Preheat: 1500-1550F(815-845C), equalize.

High Heat: 2100-2225F(1150-1220C), soak 2 to 5 minutes. For vacuum hardening, use the high side of the high heat range and soak times.

Quench: Salt or oil to 1000-1100F(540-595C), equalize, then air cool to hand warm, 150F(65C). Temper immediately. The vacuum quench rate to below 1000F(540C) is critical to achieve comparable results.



It might lose a few points of hardness over a proper heat treat but it certainly not going to anneal. Really, it's hard to *anneal* HSS.

Understand-- the CPM recommendation for annealing was 1600 F for 2 hours, but that's probably for a given blank size to soak (heat through). You're obviously heating the HSS way above the annealing temperature (beyond the liquidus temperature of HSS, for the weld puddle to form), but for a much shorter time: the time takes to make the TIG weld.

But look at WeirdSceince's empirical data which shows a 10 point loss in hardness with sand cooling. Do you think he would have lost less hardness if he quenched it immediately after welding?


Carbide, of course, won't lose anything by being brazed to a steel shank. It's a bit harder to wet with the braze, black flux worked better for me than white.

I'm curious if you can TIG weld carbide insert tools. The C2, C5 ratings are dependent on how much cobalt is in the binder with the tungsten carbide, so I'm curious if you can liquify the cobalt and get it to flow to a steel holder.

That would be another fun experiment for later this week...

lazlo
11-04-2007, 12:58 AM
Back on the original question - I've silver brazed A2 to steel shanks to make form cutters. It always cools well enough in air to be plenty hard.

I do the same Russ -- braze tool steel to mild steel shanks with Silver Brazing Wire. Based on the CPM datasheets, I didn't think welding would work well, but I'm certainly willing to try it. Sure wish I had a hardness tester :)

I do the same for carbide -- silver brazing. Forrest taught me the trick to polish off the oxide on the edge you're going to solder -- works great.

I've made a couple of Dapra power scraping tools that way.

oldtiffie
11-04-2007, 01:25 AM
Anytime I've needed to cool relatively slowly I've used:
- refractory (fire) brick enclosure to heat the tool (LPG or Oxy.Acet) - heated the tool directly in the enclosure, closed off the enclosure and let it cool over-night (house bricks work just about as well);

- garden or builders lime (dry);

- any dry sand;

- flour from the Kitchen;

- a heap of dried dirt or soil preferably "sandy" but dry clay at a strech;

Annealing/tempering? Engine oil or what ever is handy.

Hardening? Engine oil or whatever is handy.

When to "dip" when hardening? Just before when the job starts to "sweat" under the torch.

When to dip when annealing? When the colours are "right".

Air-coolng is mid-way.

According to "the book"?

Don't think so.

Does it work? Yep - mostly.

And if it don't?

Start all over.

This is all "rule of thumb" and "set of pants" stuff but it works more or less more often than not.

I do have a digital infra-red? thermometer.

I do quench in water when grinding if the tool is too hot to handle but has not "started colouring".

I am aware of the effects of micro-cracking and "chilling" and losses by the "heat-sink" effects.

But despite all this (and me!!) it works for me - more often than not.

lane
11-04-2007, 01:07 AM
Lazlo NO just saw a piece of CRS what ever Dia. weld 1/4 or what ever tool bit to it with Nickel rod. drop in bucket of water to cool of . grind bit cut part.I usually start with a short piece of bit may be one cut in half.Make a lot of threading bars that way. Did you know you can make boring bars from old allen wrenches. Don`t push it but can bore lots of little holes with one, in crs brass alum.Don`t work to good on 4140 pre heat treat though.
You might loose some of the hardness I don`t know but it will still cut , It just got to be harder than the material you are cutting.

tattoomike68
11-04-2007, 02:00 AM
HSS is overkill , you can just use a chunk of large grade 8 bolt and grind it to size and ghetto harden it.

Iv seen punches made from grade 8 bolts last for thousands of holes.

Norman Atkinson
11-04-2007, 07:42 AM
There is the old classic of case hardening with the parings of horses' Hooves and really, anything with carbon in.
One of my late lamented mates used bicycle and motor bike spokes for boring tools and Allen keys and bolts for lathe tools.

It is all a question of forgetting the shop exists and thinking.

Do you know how most of the rockets intended for London missed? The inmates of concentration camps pi55ed in the workings. It is not daft, explosives were made from urine and bird droppings.

Next?

Norm

rkepler
11-04-2007, 11:16 AM
Oh, so you're saying that the welding process will anneal-out the hardness of the HSS, but if you quench it quickly, you can temper the HSS?

I don't think that you can call melting an annealing process since the harness isn't really called out at that temperature. Annealing is a process that results in a much softer material at room temperature than an unannealed or hardened material. Melted material is melted material, the end hardness is a result of how it's handled or treated after being melted. Let it cool at 30 degF/hr and you'll have annealed material, cool faster and it'll be a bit hard, cool rapidly and it'll be hardened.


Understand-- the CPM recommendation for annealing was 1600 F for 2 hours, but that's probably for a given blank size to soak (heat through).

Nope. HSS can be really strange stuff. Likely it's stabilization time for all the components to distribute properly, or for particular crystalline structure to form, etc. That 2 hours is *after* the piece is evenly heated.


But look at WeirdSceince's empirical data which shows a 10 point loss in hardness with sand cooling. Do you think he would have lost less hardness if he quenched it immediately after welding?

I think he would have retained more, but there'd still be a small drop. I've never been tempted to measure it because it's still harder than most anything you're likely to try and cut.


I'm curious if you can TIG weld carbide insert tools. The C2, C5 ratings are dependent on how much cobalt is in the binder with the tungsten carbide, so I'm curious if you can liquify the cobalt and get it to flow to a steel holder.

That would be another fun experiment for later this week...

I'd be surprised if it worked, but I've never tried to TIG carbide at all. I suspect the result will just be a mess.

lazlo
11-04-2007, 11:42 AM
Nope. That 2 hours is *after* the piece is evenly heated.

According to the CPM instructions, you bring the furnace temperature to 1600F, and soak for 2 hours. That's how all manufacturers specify heat treating (time per thickness at a specific furnace or surface temperature), because you can't measure the temperature of the core:

From the CPM M2 datasheet I posted:

Annealing: 1600F(870C), hold 2 hours, slow cool 25F(15C)/ hr max. to 1000F(535C)

rkepler
11-04-2007, 03:04 PM
According to the CPM instructions, you bring the furnace temperature to 1600F, and soak for 2 hours. That's how all manufacturers specify heat treating (time per thickness at a specific furnace or surface temperature), because you can't measure the temperature of the core:

From the CPM M2 datasheet I posted:

Annealing: 1600F(870C), hold 2 hours, slow cool 25F(15C)/ hr max. to 1000F(535C)

Maybe you can point out where it says "per inch of thickness" in your excerpt. I sure can't see it, suggesting that the spec is *after* the part is at temperature.

lazlo
11-04-2007, 03:09 PM
Maybe you can point out where it says "core temperature of 1600F" :D
All heat treat documents specify surface, or oven temperature, because there's no way to measure the core.

Random example, notice the verbage: "Heat at XXX degrees for 1 hour per every N inch in sectional thickness." In other words, heat your oven to 1600F, and let the HSS heat for 2 hours per inch of thickness. Machinery's Handbook is written this way as well:

http://www.patentstorm.us/patents/6402863-description.html

"Existing heat treatments for 9Ni-4Co-0.30C class steel alloys-generally include a normalizing step comprising treating the alloy at a temperature of approximately 1650 F. for 1 hour per every 1 inch in sectional thickness, and austenitizing step comprising treating the alloy at a temperature of approximately 1550 F. for a period of 1 hour per every inch of sectional thickness of the part or body formed from the alloy, and a tempering step which comprises treating a body or part formed from the alloy at a temperature of approximately 1000 F. for 2 hours plus an additional 1 hour for every inch of sectional thickness of the part or body."

lazlo
11-04-2007, 03:22 PM
By the way, welding heat treated materials like 6061 aluminum is problematic for the same reason as welding heat treated HSS: the elevated temperature in the heat affected zone anneals the heat treatment, which in the case of 6061-T6, for example, weakens the material.

Here's a great article on the loss of tensile strength in 6061-T6 from welding. Like I posted originally, and confirmed by WierdScience, the loss of hardness and strength is large in the heat affected zone, and drops off quickly the further the material is from the weld line:

I have problems passing the tensile test requirements [welding] 6061-T6 (http://www.esabna.com/us/en/education/knowledge/qa/I-have-problems-passing-the-tensile-test-requirements-with-6061-T6.cfm)

http://www.esabna.com/us/en/education/knowledge/images/HardnessProfiles.jpg

Fig 2. The higher the heat input during the welding operation the more pronounced the reduction in hardness in the heat affected zone.

CCWKen
11-04-2007, 03:50 PM
Just for informational purposes, it does work. It ain't pretty but it worked and that's all that matters. I didn't even try to re-harden or worry about the softening. I welded it up, dressed the welds so the die would center and sit flat in the punch-press then made the punch. I happen to run across a small table nut that was the right size and hard as rock. I gound it for clearance to the die and made my pieces. Worked like a charm.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-1.jpg

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-4.jpg

DR
11-04-2007, 04:44 PM
Nice work Ken.

FWIW, that would have also worked almost as well using mild steel as the punch and die. Punching is not cutting, it's fracturing the material, that's why mild steel will work for limited runs.

rkepler
11-04-2007, 05:45 PM
Maybe you can point out where it says "core temperature of 1600F" :D
All heat treat documents specify surface, or oven temperature, because there's no way to measure the core.

It's specifying the soak time. Read this page: http://www.crucibleservice.com/eselector/general/generalpart2.html

oldtiffie
11-04-2007, 06:01 PM
Just for informational purposes, it does work. It ain't pretty but it worked and that's all that matters. I didn't even try to re-harden or worry about the softening. I welded it up, dressed the welds so the die would center and sit flat in the punch-press then made the punch. I happen to run across a small table nut that was the right size and hard as rock. I gound it for clearance to the die and made my pieces. Worked like a charm.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-1.jpg

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-4.jpg


Thanks CCWKen.

The "acid test" test is whether it works or not.

To put another way: "the proof is in the pudding" - so to speak.

A very nice job - it works, made of ordinary run of the mill stuff that can be found in any HSM shop - and its pretty too!!.

Pics showed it perfectly.

So all the HSM-ers can now know that the process works and is quite achievable by the average HSM-er in his shop.

Can you tell us what the type of welding rod/filler and process were?

This is real creative HSM "stuff" - making the impossible possible.

The quote by DR is great and points out that the punching process if "pushing it out" and not "cutting" it.


Quote from DR:
FWIW, that would have also worked almost as well using mild steel as the punch and die. Punching is not cutting, it's fracturing the material, that's why mild steel will work for limited runs

So the abrasion resistance is quite high - as it needs to be - same as in "drawing" die sets.

Great job, great advice and great pics

Can you tell and show us (pics) how you made the drawing die set for the "top hat" please as that looks to be an interesting job as well.

lazlo
11-04-2007, 06:02 PM
The horse is dead Russ, but since this Forum lives for that... ;)


It's specifying the soak time.

Yes, that's exactly what I said: the 2 hours is the soak time:



According to the CPM instructions, you bring the furnace temperature to 1600F, and soak for 2 hours.

Nope. That 2 hours is *after* the piece is evenly heated.

lazlo
11-04-2007, 06:05 PM
The "acid test" test is whether it works or not.
...
So all the HSM-ers can now know that the process works and is quite achievable by the average HSM-er in his shop.

Or, like DR said, you could have gotten the same results from using mild steel.

rkepler
11-04-2007, 07:08 PM
Lazlo, you said here:


Random example, notice the verbage: "Heat at XXX degrees for 1 hour per every N inch in sectional thickness." In other words, heat your oven to 1600F, and let the HSS heat for 2 hours per inch of thickness.

If someone was to follow your instructions they'd end up with some really long times in the HT oven. I was simply pointing out that the times spec'd were total time at temperature and not time per inch as you thought and said.

I'm pretty well done with this. It's definitely into the sadonecroequinophilia stage. You can have the last word.

lazlo
11-04-2007, 07:40 PM
I was simply pointing out that the times spec'd were total time at temperature and not time per inch as you thought and said.

Russ, I'm definitely not trying to get the last word in here, but I think we may be talking past each other, especially with respect to the meaning of "Soak Time."

The purpose of the soak time is to get the core of the piece you're heating to a certain temperature. So when you get heat treat instructions from the metal vendor, CPM, or Machinery's Handbook, they specify "ramp time" and "soak time." Ramp Time is the time it takes the oven to get to the right temperature. Soak time is how long you need to leave the workpiece in the oven to get the core to the correct temperature.

I have an Omron E5AK digital controller on my heat treat furnace, and it has programmable parameters for the ramp time (how quickly it brings up the temperature in the oven) and soak time (how long it holds the oven at that temperature).

So quoting "The Steel Heat Treatment Handbook":

"By heat-up and soak time we mean the time it takes for the heated workpiece to go from starting (room) temperature to the preset temperature in its core.

Current determinations of heat-up and soak time are based on either a very conservative and general rule (e.g., 1 hour/inch of cross section) or some emprical method, the results of which differ substantially."

So like I said earlier, CPM's directions are to heat the oven to 1600F, and then soak the HSS for 2 hours (at 1600F).

Here's a less pedantic description of the same definition from EvenHeat: a manufacturer of heat treating ovens

http://www.evenheat-kiln.com/technical/heattreat/heattreat.htm

Specific Heat Treating Data

ATS 34, 154CM S.S. Heat Treat Procedure:

This is an oil hardening grade of steel which will require oil quenching. The oil should be warm, thin quenching oil that contains a safe flash point. Olive oil has been used as a substitute. As a rule of thumb there should be a gallon of oil for each pound of steel. For warming the oil before quenching you may heat a piece of steel and drop in the oil.

1. Wrap blades in stainless tool wrap and leave an extra two inches on each end of the package (This will be for handling purposes going into the quench as described below). We suggest a double wrap for this grade. The edges of the foil should be double crimped being careful to avoid having even a pin hole in the wrap.

2. Place in furnace and heat to 1900F. After reaching this temperature immediately start timing the soak time of 25 to 30 minutes.

lane
11-04-2007, 07:54 PM
Irregardless of who said what ,are what the books say. If you do not try something you want know the out come.The man did and was happy with the results.That in its self was all I was ever trying to say.You can read information in books ,you can ask questions of other people and will get all kinds of answers. but the only way to learn is try for your self. If i does not work try something else.That is what being a machinist are home machinist is all about. What have you got to loose trying something.

J Tiers
11-04-2007, 08:08 PM
O-1 works pretty well, and there is certainly less controversy about it!

One-off punches are anything that will work..... I can vouch for CRS working once, even 3 times......

My punch and die books mention parts of the tool being left soft or made of softer material so they could be peened back to size after wear.

wierdscience
11-04-2007, 10:47 PM
That looks good Ken,nice job as usual.

CCWKen
11-05-2007, 01:51 AM
Ah shucks Darin, you're too kind. I took an ugly path to get there though. :D

The top-left two trials are just to get the shape of the hat top. I didn't have the compression skirt on the press so you can see the amount of draw. The top left (first try) is torn because I didn't have enough edge relief on the draw die. The rest were trial steps to the finished product.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-3.jpg

oldtiffie
11-05-2007, 02:10 AM
Ah shucks Darin, you're too kind. I took an ugly path to get there though. :D

The top-left two trials are just to get the shape of the hat top. I didn't have the compression skirt on the press so you can see the amount of draw. The top left (first try) is torn because I didn't have enough edge relief on the draw die. The rest were trial steps to the finished product.

http://img.photobucket.com/albums/0903/CCWKen/Projects/Model%20T-TT/DoorBumperMount-3.jpg

Thanks CCWKen.

That is great stuff.

I am sure that many of us really appreciate the pics and info.

Can you post the clearances etc. and pics of the press you used please?

oldtiffie
11-05-2007, 02:18 AM
O-1 works pretty well, and there is certainly less controversy about it!

One-off punches are anything that will work..... I can vouch for CRS working once, even 3 times......

My punch and die books mention parts of the tool being left soft or made of softer material so they could be peened back to size after wear.

Thanks JT.

A very good "practical, hands-on" post from experience.

Any "rules of thumb" advice and/or links please that this HSM-er at least can relate to and use?

I am sure that there are a lot who would appreciate it.

My books for that and a lot of other things got "lost" along the way somewhere.

Could you recommend two (or more) books that the HSM-er can relate to and use that are still available.

This will enable me at least to get it right a bit more often and to give a bit of the "hit and miss" approach away.

You are obviously the "been there, done that" bloke to ask.

Advice from others will be very much appreciated as well.

Norman Atkinson
11-05-2007, 07:10 AM
GHThomas writing in his two books Model Engineers Workshop Manual and Workshop Techniques described both a spring punching design in the first book and a staking tool in the second.

I have built the Staking tool and will be adding the drilling attachment from the castings in HemingwayKits.

After all, it is commonplace in clockmaking and live steam to have these goodies.

DR
11-05-2007, 08:53 AM
As I mentioned mild steel will work for short run punches/dies.

A point to remember, punching is fracturing, speed is essential to fracture the panel.

In draw forming operations the opposite is the rule, slow speed allows the material a bit of flow time to prevent fracturing.