Drilling through firewall with step bit issue

Not sure what's going on, but it's taking forever and at 1" so far (I need 1-1/4" for the boot) it looks like it has developed a huge flange. I'm not sure how to fix the flange, it's like 1/2 thick now. Any suggestions?

 

Maybe the bit has lost its edge... perhaps a new step bit will finish the job.

 

I don't see any evidence of drilling. Use a quality step bit (no harbor freight) and go slow.

 

Harbor freight unibits are really good. Just saying. Everyone I know uses them

 

Sure. Once maybe. Because they're garbage. Klein and Greenlee are decent, but they are $50. Not fuc$ing up a hole, priceless.

 

Looks like you are drilling into more than a single layer. Is there are reinforcing plate, flange, or tube back there??

 

I don't know your experiences with harbor frieght unibits, but they're the best unibits I've ever used, no other bit can hold a candle to them. Most of the stuff harbor freight sells is garbage yes, but they have some things that are actually really good, like the unibits. Like I said, I know about 50 people that use them religiously with no issues at all

 

Greenlee. Everything else is shit. The new double cutting edge Greenlee is the bomb.

 

Also, with the flange ordeal, try drilling from the other side, usually you can get rid of the flange by doing that

 

Careful drilling from the opposite side. If your bit catches that insulation, it’ll pull it all out like cotton candy.

 

This is true

 

I was so looking for a pic of a hole going through a brake booster....such a disappointment. But like 10 layers of sheet metal is kinda cool

What are you drilling for anyway? There is a smaller gromit right next to that area

A step bit isn’t made for that thick of metal.

 

I see no evidence of oil? Always use oil when drilling steel. Aluminum requires a different fluid.

 

Eldedo is right, you probably dulled your tip without using oil (highly needed for thick steel) but you dont need oil for aluminum. I agree, try the back side with another step drill with deeper steps that should do it. Looks like quite a rathole right now, is that right above the harness near the brake booster? Be sure about the wires behind it, I believe they’re pretty close to it. As for a grommet, looks like it may need some tubing for the wires in that thick part, a standard grommet wont fit.

 

You're pushing the metal around as opposed to cutting it, so its not catching the bit edge for one reason or another (doesn't look burnt so probably OK with your speed). Still, clean the bit, inspect it, and use some sort of cutting fluid or even a stick of lube. If it gets too much, you can probably pay a tech to try a pneumatic hole punch from a sheet metal shop.

 

Whatcha drilln' fur?

 

dull bit. heating and pushing the metal vs cutting it. 1-1/4 is hole saw range for me. Removing much less material than drilling but thats water under the bridge since youre at 1in already. Fresh bit and keep going. Ive had the flanges get cut off on the next step. You have to go slow and NOT give it all the RPM's your drill motor has. You're most likely using High speed steel bits. Also a little cutting fluid would help but on mild steels not necessary.

 

Gloryhole?

 

is that the carpet on the inside?

 

The swearing does help