Hot Rods hole saws keep dulling.how to cut holes in metal

If ya don't have a slow speed drill, Use the on again off again with the trigger method. Keep the pressure steady.

 

Haven't seen it mentioned yet but Blair rota broach hole cutters are the ***s for making holes in metal. They are pricey but last forever.

 

I've stuffed paper towel or rag bits into the saw tube and saturated it with oil. You can refill the oil from time to time - seems to help.
A tip from Nostalgia Sid - thanks again Sid.............

 

My visor don't come off the car.as well!as most of the stuff I'm trying to put holes in.my interior I want to do aircraft style so a lot of dimpled holes are going in.so a drill press isn't an option.plus mine is damaged anyway and don't work anymore.

Yeah I seen the die that does it all...too bad I don't have that one

 

You can get dimple dies that punch the holes.

 

Millwaukee (?) hole saw with 3/4 " plywood block clamped behind- Millwaukee (?) 3/8 " hand held drill. SLOWLY- no oil, no air, no problem ( I just can't spell gud).

 

Ya the hole saws I use are nothing special, I think they're milwaukee, I just get em at the local hardware store. Trick is low speed, pressure and cutting out. Same with drill bits.

If you go at it full bore you just harden the cutting edges and then you're back at the store buying another hole saw. My grandpa has had a Lennox hole saw kit for at least 10 years and they still cut like new

 

If you use cutting oil, not WD-40 and about 180 RPM you should be able to drill your entire visor with one hole saw. To toast a hole saw after 4 cuts, you are doing something wrong, you are only cutting 18 ga. sheet metal!

 

Just buy the punches, more tools is always a good investment.
http://www.ebay.com/sch/i.html?_odk...&_nkw=knock+out+punch+set&ghostText=&_sacat=0

 

Rotabroach, anyone?

The conventional sort of steel-cup holesaw produces an approximation of a round hole, good enough at small sizes or for joints where any irregularity is going to be filled with weld. But yeah, if you're going that route, moderately slow speed, not much pressure, lots of patience, 'peck' cutting to clear **** from the blade path, and lots of cutting oil or ideally flooding with coolant if your equipment will accommodate it.

 

One thing I find that drilling sheet metal is tricky - I've had good luck with backing like a 2X4, and then drilling on an angle, and then when the first spot breaks through, slowly rotate your drill "coming off" as you drill through. "Cutting on" will cause it to grab. This way, only a few teeth are cutting, and then they get a chance to cool as it leaves the workpiece. Drill as slow as you can too - if you do the math on the OD of the hole saw, you can figure the cutting speed.

 

I have Matco hole saws and some from McMaster-Carr
I mainly use them for notching tubing and I use cutting oil. They have all lasted much longer than I expected.

 

A 2 1/2 knockout punch runs at least 100$ at least! Not looking to spend that for such a simple tool

 

I've tried going 'slow' not much changed if any...going to try and sell my dimple die tool and buy the super expensive one that cuts too...any one want it!! 40$!

 

No thanks, I'm saving up for a
Greenlee 7238SB

 

Thats not a dimple tool

 

Maybe you could rent a knockout punch. Try your rental yards or construction places.

 

I've seen that even the knockout punches don't actually cut the size hole it says.so my die wouldn't work in that

 

But that was my next idea.also I plan on doing them on more than one car so it would pay to just buy another dimpler

 

This is a wacky idea but what the heck: If your hole saw has a 1/4" pilot hole you might be able to put a long bolt through it, and the pilot hole in the work, and a piece of plywood, and a washer, and a spring, and another washer, then a nut. To support the back side and give some downward pressure.

 

That sound like an awesome idea.
Actually I'll give that a whirl tomorrow

 

I'm not following ya,what's the spring for? And are you suggestingusing the saw as a punch? I think it would just distort the metal all to hell. But who knows.I'm all for ideas,so please don't take it the wrong way I'm just trying to figure out what your idea is

 

Hole saw as a hole saw. The spring on the back side would be to pull the saw down onto the work. As others have said, you really need a lot of pressure and slow speed. You are cutting about 6 inches of metal at the same time (the cir***ference). Picture cutting through a 6 inch slab on a band saw. I'm thinking a strong spring, like a valve spring. It would spin with the saw, probably, maybe not.

 

Years ago I bought a set od Blumol hole saws. That was one of the best investments I ever made. I have not burned up any of these hole saws. I owuldn't have anything but Blumol hole saws

 

Ohhhh I got ya

 

Bet I find a use for a couple of old king pin bearings

 

Yeah, this was a hoot:

 

Did you weigh it before and after?

 

No, but the slugs were about three pounds worth. Not enough to make any difference (especially in my car) and almost no one will ever see it but I know it's there and that's what counts (or so I've been told).

 

BLAIR Hole Saws! Little Pricey but you get more than one hole out of'em!

All these holes with one bit...still sharp!
Slow + 30W Oil