air hammer technique

I have a Silverado pickup with a bad trans and the lovely allen head bolts holding the torque converter to the flywheel. I got two of them to come out but rounded one. Seems like air hammer to dig a groove and "push" the bolt ccw to loosen is the next step. I only had a chisel tip and tried just a couple of hits. I only get one impact before the bit jumps off. I now have a fresh bolt cutting bit. is this the right one to use? Is there any good technique or is it just going to be press the trigger then reset the hammer and repeat? Will the bolt cutter be more effective?

I know exactly how to do what you're asking and i'm dubious that i could relate it well enough over text to help you. It sounds as though you understand the basic idea and are just not comfortable/experienced with the gun itself. The basic idea is to start by cutting straight down on the bolt head, but offset to one side sort of like a hand on a clock. Once you've dug that groove sufficiently deep you then angle the gun into it so that you would be pushing the bolt in a CCW direction. I guess the main trick you may not be using is that the air hammer requires you to give a constant steady push (if not whole-body shove) into the work piece or the tip will just bounce all over the place.

I used to have to chisel out those E36 M3ty GM converter bolts frequently when i worked in a trans shop (there is also a technique involved in their stupid trans pan drain bolts!). By the time you do a few you'll be a pro, but if you bugger up this first one bad enough you can always just go at it from the side and chisel the whole head off the bolt and then try to dig the remains out of the converter once it's out of the car. I've never had to do that and you will probably get the bolt out in one piece once you starting pushing the gun against the bolt harder. Good luck!

I've never had luck with an air hammer for this reason. I've removed a myriad of fasteners/drain plugs with a ball peen and a chisel though.

You generally have to point it right at the center to make a groove first then add some angle to twist it.

Vigo wrote: I know exactly how to do what you're asking and i'm dubious that i could relate it well enough over text to help you.

Your description definitely helped. Truck way up on stands, half sitting up and leaning on a shoulder I had no leverage. Now I know that I need to reposition myself to lean into it to get bite. Thank you!

Hope this all works out when and then when it does, come back and ask about air guitar techniques. That I may be able to help you with.

You want one with a throttle knob on the bottom of the grip and an easily modulated trigger (if you ever find a used Chicago Pneumatic 714 for cheap, buy it) so you can gradually ramp up the power and control it until it's dug in, then go at it hard. Also, allen head bolts are usually pretty hard which ups the difficulty, still doable though. I actually used an air hammer to back out two high grade hub bearing bolts with half the heads ground off a couple months ago, no problem.

The way I do it is to start with a fairly sharp chisel type bit on the edge of the bolt head with the chisel edge perpendicular to the bolt edge, start slow until it's dug in a fair amount, then more power to get it dug in good, then angle over to drive the bolt loose, you'll be hitting it equally or more in than you are over, but it will work.

Like Vigo said it takes some practice but it makes sense fast. Just remember that if the bit slips off you LET GO OF THE TRIGGER, sometimes the gun will rattle the hell out of your hand if you stay at WOT with it off the work. WEAR EYE AND EAR PROTECTION

Do they not have a hex head outside too? I just did them on my car(07 express drivetrain) and they had an allen center with a very shallow 15(or 16) mm hex on the outside that a 6pt socket worked on. I did have to get bolts red hot to get them to break free.