Instrument knock out tool

[Charles in SC]

I am thinking about useing one of these to cut the round holes for my instruments. My panel is .090 thick. Will one of these tools work well for this or is there something better? I am looking for something to do during the cold weather so I can sit between two heaters and be productive.
Thanks!

 

[Mel]

.090" might be a little thick for the common instrument panel punches that don't have bearings.
It will probably work, but it will take some "grunting". The ones without bearings work very well up to about 0.063".
For .090" you may need to go to a more expensive punch with bearings.

 

[MJarreau]

Electrical Punches?

Mel,

Is there any reason punches used in electrical panels will not work? We use Greenlee punches all the time, even with 316 stainless.

Cheers,
Michael

 

[Mel]

Mel,
Is there any reason punches used in electrical panels will not work? We use Greenlee punches all the time, even with 316 stainless.
Cheers,
Michael

Greenlee punches are great. Most of them have bearings. When using "electrical panel" punches make sure you have the correct size.
2 1/4" and 3 1/8" are not common sizes for these.

 

[terrye]

.090 panelf

I cut instrument holes in an .090 panel for my Cessna 150. Mel is right, the punch works better with bearing(s). Check your local bearing supply house for a small ball thrust bearing that will fit between the bolt and the punch.

 

[Mike S]

Other option is to use a fly cutter.

BE CAREFUL if you go this route, they can be dangerous.

 

[mikeasselin]

Instrument Knock out tool

Our local EAA chapter 245 has a set of knock out tools and the limitation specfied in the instructions is 1/16 inch. We tried it on a 0.063 and we needed a lot of torque to get it puched. The instuctions suggest to start the die then rotate to partially start the cut then once fully rotated complete the punching.

 

[Mike S]

The instructions suggest to start the die then rotate to partially start the cut then once fully rotated complete the punching.

I had to do this on my panel, additionally you will find the cutter works better at the start than the end of the cut, a trick I used to get the last of the cut done was; I would get the center bolt tight, and smack the cutter around the edges with a dead blow mallet a few times, and re-tighten the bolt----repeat as needed.

You have to have the back side of the die solidly supported to do this, then it works well. You are only trying to assist the cutting process that is driven by the bolt, so go easy with the mallet.

Good luck, Merry Christmas