Impact hammer for restringing

[Tom Cole]

Lance Lafargue wrote:
> 
> I mostly worry about a pin driven in at a less than perfect angle,
> enlarging the hole.  There is no room for this kind of mistake.  I also
> don't want to scratch the plate with something that is too powerful..  I
> envision a bull in a china shop scenario and don't want to negate the
> quality/integrity of the tuning pin hole, or my plate finish.  Thanks for
> any ideas.

Lance,

When I first start the pin into the hole, I don't jam the air chisel
onto the pin but start with a light touch. Also, it's a lot like
drilling the holes in a new bridge cap. You position your body over the
machine to get a good feel for the angle. Take your time with the first
few pins and they will tell you how they need to be driven, the same as
when you're driving them by hand. Once you get the rhythm, you might
even think that you have more control.

A couple of caveats:
	1) knowing when to release the trigger so that you don't over drive the
pins. I remember doing it by eye rather than using some kind of a stop
which would damage the plate finish.
	2) the air chisel people will tell you to put drops of air chisel oil
in the intake frequently. If you do, you might want to wrap a rag around
the exhaust which exits toward the point of the tool. Until someone
invents a rear exhaust tool, I'd run mine dry, though. I figure that
shelling out $20 to replace it now and then is worth the peace of mind
knowing that I'm not spraying oil on the tuning pins.

If you do have concerns, you could drive some test pins into a scrap of
pin block material and test for torque. Also check if there's a
difference between using a sledge and using an air chisel. If you do,
let me know what you find out.

Regards,

Tom

-- 
Thomas A. Cole RPT
Santa Cruz, CA