Through bumperettes muffler. Ben McFarland of M&K fame is doing the welding. He is an artist. Will be post in Technical once it's done, if it ever is.

Clearly! I wish I could weld like that. That's like weld porn man.

I will talk with them about these too.

The greatest attribute, I think, is that it needs to transfer the energy from the hammer efficiently and directly. To me, that also implies durability in terms of hammer blows.

More to the story, I had a male form made, it was cold rolled and it worked well but it eventually wore out. So I ordered 10 more forms of the same steel (waterjet cut... 5 is only a little more than 1 and 10 is only a little more than 5) and it was junk. Machine shop said it was the same steel. No way it was. So they said I should spec the steel myself.

Just wait for more pics. :eek:

Very nice. That looks much like my 911 R muffler, though, which really isn't a "muffler" at all. It's essentially just a set of megaphones that pass through a stock "banana" muffler can that is completely hollowed out. The megaphones are perforated where they are inside the muffler can, so they do kind of utilize the big "banana" as an erstwhile "balance tube" or chamber. This "muffler", however, is "megaphone loud". I added the little inward scallops in the tops of the megaphones to clear the heater tubes going to my shortened SSI's, so I can retain heat. Oh, and yeah - my welder (me) really sucks compared to Shaun's....

http://forums.pelicanparts.com/uploa...1565552511.jpg

So, with the inlets and outlets directly lined up, what are you doing internally? Any baffling or re-direction, or does exhaust flow straight through?

Pretty cool Jeff. But those welds are not mine, goodness no, Ben McFarland is the artist on my can.

You know I have to ask Ben about the internals. I helped him prototype the very first M&K for Carreras and that can was really light. I just shipped this one back and it was 20 lbs I think. There's something in there. I have stock cams in my 3.2 but a maxed out SW chip for George's headers and this muffler so I'm hoping it's basically just a straight through design with no muffling. I am sure I can convince myself of virtually any hp gain I can dream up. :D

Nothing like a sound dyno! It sounds louder so it has to be faster! My brother just installed a 2 in 2 out M&K on his 3.2 with SSI's and it sounds nice! Not obnoxious like his B&B... which is still fun, but the M&K doesn't have near the drone the B&B setup has.

Yes, Ben is an absolute master. I've had three of his mufflers over the years. It's a shame to hide them under a car - they should be hanging on the wall as "garage art".

Just as a sort of precautionary tale, I might recommend having an alternative "real" muffler on hand for when "megaphone loud" gets to be too much. I alternate my "R" muffler with a modified Dansk "RSR" muffler (purchased from our host). The "RSR" muffler has the stock inlet locations, which are inboard of the outlet locations, along with having some actual baffling inside.

When I shortened the SSI's, I did so by cutting off the "S" bend on the outlet pipes and welding a flange right up against the collector end, the way George's headers are made. I saved the "S" bend pieces and welded flanges on the cutoff ends, so I can just bolt them back in place when I want to run a muffler with the stock inlet locations.

Here's the "RSR" muffler. It comes with dog legged outlets to go under full length bumperettes (instead of the short ones I run), which I cut off and replaced with the straight stainless outlets shown. This one is far from "quiet", but it does make for a worthwhile reduction in noise when that's what I want. It takes maybe fifteen minutes to swap them out.

http://forums.pelicanparts.com/uploa...1565554610.jpg

That is definitely good advice about having another muffler on hand but tolerance to loud 911 music is substantial. Here's a funny story you will appreciate. So I prototyped the Carrera outlet for Ben and I got to keep that first muffler for helping. It was a long can design that made for carb-like instantaneous revs and anywhere from 5K to 7K (SW chip) it sounded like a F1 motor. It was glorious, should never had sold it with the car.

Anyway, I used to rev that thing all the time for the sound. Was in small town traffic one day and there was this Harley and he's making all kinds of big Harley sounds when he comes up to me and passes me and then me, him and back and forth for a bit. I'm just doing light revs for fun and sound, nothing too loud. But when we're together, he's into his sounds, and it's really annoying, so I park it at 4K when next to him to drown him out and that makes him just make more noise to which I go to 6K+ and that makes him ride away up the side of the road to get away. Mind you, this is glorious F1 music, I'm not sure why he wouldn't want to revel it just as I was. Maybe 10 minutes later I somehow catch up to him and he looks at me and yells, "not you again" and rides away with a snarl. You sorta had to be there, it was really funny.

I love it. You clearly "saved more lives" that day... ;)

As far as pounding on the edge of that steel plate, keep in mind that if you are dealing with being on the limits of non deformation, anything other than a perfect 180 degree angle will cause other issues.

Shaun, If you can get me something on how you'd like the piece built, I could take it to my BIL and see if he could mill it for you. If I tell him it's for a friend he'd do it for a little bit of nothing. He's a car guy.

Had sort of a similar thing happen in Lima OH with two Harley riders at a stop light. Both were revving back and forth. I pull up, hit the throttle, both of them look over and give me the thumbs up. All three of us at the stop light going back and forth while laughing.

Jeff you seem to understand guns and metallurgy quite well, and other things too I suspect. What can you tell us about women? Got any suggested specifications?

OMG...

Lots of incorrect here. Any alloy steel can be case hardened by nitriding.

I’m not really clear on the application but through hardened 4340 is close to the bottom of the list for what sounds like it will be used as an anvil...

Do you need to weld to this? That’s another aspect of the material spec. Do you plan to machine it first and then heat treat?

Hardox 400 could be an option depending. You won’t successfully weld it without a weld procedure but this gives good hardness and toughness and it is readily available in plate form. QT400 May be a good option as well.

:rolleyes: About the only thing you got right is the notion that it is possible to case (surface) harden a through hardening steel like 4340. There are, however, less expensive low carbon steels that are entirely suited to surface hardening, so there is rarely any reason to surface harden a high carbon steel that is meant for through hardening, such as 4340.

In this application, merely surface hardening the material would be a decidedly bad idea, so I did not touch on that possibility, and did not recommend any steels suitable for such.

No one surface hardens an "anvil", or anything that will be subject to heavy impact such as Shaun is planning for this piece of material. The result of such a practice is that the underlying, still relatively malleable material will be deformed when struck, eventually deforming enough to induce cracking on the hardened surface material. Kind of a "hard boiled egg" effect, for sake of illustration.

We want a uniform hardness throughout the material, and will settle for a lower Rockwell hardness to achieve that, while retaining some malleability in the hopes of avoiding cracking. S5 and S7 are, of course, the "go-to" steels for this (as I mentioned in a subsequent post), but 4340 is often, as I said, available just laying around a lot of machine shops, where S5 and S7 are a bit harder to come by.

The proper application of surface hardening is to reduce surface wear on sliding, reciprocating, or revolving contact faces of things such as gear sets, bearing faces, guide tracks, crank shafts, and similar applications where an underlying malleability, or "toughness" is desired to help prevent breakage. It provides a far harder surface than through hardening can without resulting in the underlying material becoming excessively brittle and prone to breakage.

And finally, no, 4340 is decidedly not "close to the bottom" for use as an "anvil". Many top notch commercial anvils are made from the very similar 4130 and 4140 alloys, and through hardened as I recommended. I only recommended 4340 because of its common availability, and to keep things simple. If either of those other two are available, Shaun could use any one of them interchangeably for his little project and never know the difference, or one of the "S" series steels I also recommended.

^^^ hmmm, so you know more about material selection than a Professional Engineer (Mechanical) such as myself that has been doing this for close to 20 years?

Maybe you can send me your contact information and you can help me with the material spec I am writing right now for our API 6A 21st edition compliant pressure control equipment. It only needs to be good for a 30,000 psi pressure test.

What Rockwell Scale are you referring to? Do you know? Rockwell C? Norman Rockwell? Rockefeller’s Center?

You are even more out to lunch with your follow up post here. You can nitride (liquid or gas) any steel to give a case of ~ 0.005” with a RC hardness in the mid 50s.

For something seeing impact loading (such as the application described in the OP), through hardening to RC 43 (Rockwell C, not Rockefeller’s Center FYI), is going to be too brittle for most alloys.

4130 and 4140 are not totally similar to 4340. 4130 and 4140 are similar to each other to the point that I have a material spec for some pressure control equipment and dienhole tools that I have designed that allows either. For some applications, often 4130 is selected because it has a lower carbon content so that it can be more readily welded. Either would need a weld procedure and some form of post weld heat treatment but 4130 is certainly more forgiving. The material spec I am working on right now is to replace 4130 / 4140 because on large billets, you can’t get consistent through hardness on these alloys. The center of the steel is always soft (but I assume you already knew that). We are switching to 8630 or 8630MOD. I’m going to decide this today.

Ideally for an anvil, you want a tough material with a hard surface that is easily work hardened. So as it wears, it continues to get harder but the support material maintains its toughness. Gears and crankshafts are often made from 8620 Carburized to RC60 with a 0.060” case but I don’t think you can get this in plate and you certainly wouldn’t be able to weld it without damaging the case.

S7 or other tool steels that you allude to are laughable for this application. Tempered S7 while tough for a tool steel, is too brittle to take any sort of impact and I’m quite unsure how you would weld it to the rest of the fixture. It’s not just a matter of doing localized stress relieving with a torch post weld because all you are doing is chasing the heat effected zone around the part.

Again, not fully understanding the application, Sean May be able to just go to Home Depot and buy a chainsaw bar, cut it so size, weld it to his fixture, heat up the part that’s going to see the impact to blue and dip it in old motor oil. It’s pretty farmerish but would give a hard surface where it is needed and the rest of the material would remain tough. I have no idea what the alloy is, nor how the welds at the other end would hold up to impact...

Jeff, you are in over your head here. I trust your experience with firearms, and look forward to your posts on that subject matter. As a design engineer, material selection is somewhere that I am a subject matter expert - quite literally, this is what I get paid well enough to support my family, and my Porsche habit to do.

Heavy duty
 

Perhaps you should think about a thicker piece of steel to hammer on? Several years ago, I needed to replace/rebuild the external oil thermostat on my SC. Access to the nuts on the thermostat is limited so I dropped the whole thing, themostat and all 4 lines. I still could not get the nuts loose so I wound up making this wrench from a piece of scrap steel that I had on hand. I used a very heavy (5 foot long cast iron) pipe wrench to hold the themostat and whacked away on the steel wrench with a hand sledge. The heavy wrench transferred the shock more efficiently and the nuts were loose in short order. I didn't even damage the threads! Here's a picture of the wrench.

http://forums.pelicanparts.com/uploa...1565607149.jpg

http://forums.pelicanparts.com/uploa...1565607175.jpg

I would still like to know what the application is. If it’s anything like straightening your grill ribs, you’re not actually hammering on the steel directly. You have something in between the steel and the hammer.

So what the hell are you doing with this thing?

He linked it in one of his posts here. He's using it to straighten bent bars on engine grilles.