Chisel bounce

[paulrsmith357]

I have a newbie question. When I am cutting metal on the anvil with a chisel. How do you stop the rebound hit of the chisel??

[Frazer]

If you are cutting directly on the surface of your anvil, the hardened face may be reflecting that energy back up making the bounce more significant. Perhaps using a mild steel cutting plate you put between the anvil and whatever you're chiseling will help some. It will also save the cutting edge of your chisel (or the face of your anvil) if you go all the way through. Another option would be a holdfast of some sort. The last thing I can think of at the moment is to get the piece of steel hotter. Of course that doesn't really help if you're cold chiseling..

[John B]

If you are cutting hot, you should not get a rebound, if you are, then material needs reheating. When you place a cutting plate under the workpiece, it may rebound then as you chisel until it is through.

If you are cutting cold, then patience is the key, line up your chisel, hit, pause and then move chisel on into next position and hit again, Material may bounce on impact and is usually due to the workpice and the supporting item not being in perfect alignment, allowing top piece to spring/deflect when being struck.

[ThomasPowers]

Bounce is generally an issue on the first few strokes; once the cut is established you generally can hit multiple times without repositioning.  Note if you are not using a high alloy chisel you probably need to be quenching your chisel every couple of hits!  (Being able to skip quenching was what sold me on using S-7, S-1, H-13 tools as it really speeds things up!) 

Another chisel helper is a hold down that lets you use both hands for chisel and hammer. I have a drive chain that loops over my anvil and has a bar on the end I can step on to apply pressure.  I do quite a bit of incised twists and with the bar "floating" I would only get a couple of blows per heat as it would end up heading for the center of the earth.  If I had a friend holding I could usually chisel an entire S hook side in one heat.  The hold down lets me do it in "under 2 heats" usually.  A previous method was to hold longer stock between my legs while working on it.  A technique that does teach you to not work as much as the stock cools off.

[rockstar.esq]

Aside from the already mentioned ideas, here are a few more.

If your anvil wobbles, it's especially tough to use struck tooling.  If you are working alone, it's tough to use struck tooling on stock that doesn't want to lay flat (and still) on the anvil.  Trying to chisel unrestrained round stock on your own is a rodeo, if you can keep it together for 8 seconds, you're a champion!

If you're cutting thin metal, you might want to set the chisel in line with the edge of your anvil.  If possible, you can tip the chisel such that one corner cuts before the other.  This sets up a shearing cut which is very useful for trimming a strip off a larger plate.

Broadly speaking, wider chisels will have more resistance while cutting than narrower chisels.  You might find that a narrower chisel actually makes a longer cut faster because it achieves more cutting with every hammer blow.  

It's possible that part of the rebound you're experiencing is a function of the chisel slipping after the cut.  There are top tools called "butchers" which are typically used to isolate stock.  Some butchers have a working face that look a bit like a crescent shaped chisel.  The advantage of this design is that the outside corners of the stock are "hemmed in" by the curve.  That minimizes the distortion on the stock you're trying to leave alone.  Since the edge is curved, it's only making contact at two small points on the stock to initiate the cut.  That allows the first blow to really set the line.  Generally, the butcher is then traded out for a different top tool depending on what you're trying to achieve.

Finally, if you're using a chisel for hot-cutting, there's a few tips I picked up from Peter Ross.  His chisels have a few features I haven't seen together anywhere else.  First off, he shapes the edge like an axe, so that he can "walk" the chisel along a curved cut.  This also reduces surface area when starting a cut so that first blow really sinks.  Second, he blunts the edge such that it has a 1/16" flat.  When cutting hot stock, this tends to reduce the ragged edges at the bottom of the cuts because it forges the rag outwards on either side of the cut.  It also makes your "edge" tougher in use against hot metal.  Third, he grinds what looks like a false edge on the leading edge of his chisel.  It's used to sight down the tool so you can tell if your cutting edge is lined up without bending, or stooping.

 

[Chad J.]

These are great tips, I haven't done much chisel work yet so this will be bookmarked so I can review again. 

 

And again... and again...

[paulrsmith357]

Thanks everyone for the great tips. I look foward to applying them as I can tell there are a few I am not doing. Again thanks!

[Hearthstone]

I'm not a total newbie, but always pick up something new or something I have already forgotten.
Thanks.

[pnut]

A chain hold down made cutting hot on the anvil so much easier. I felt like a keystone kop trying to cut a round bar without it. 

Pnut