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

I haven't tried these, but maybe helpful? From recent Sport Aviation magazine of EAA.

 

Wow guys.....them all a lot of holes!

 

We go through a lot of hole saws, as soon as they get dull we toss them rather than trying to use one that won't cut a clean hole. Normally, I just run to Home Depot around the corner and pick up a new one when we need it.

The other night ,when we were cutting the two 2.5 inch holes in the rear of my altered frame for the tube crossmember , I decided to buy a new hole saw so the holes would be perfect. When I got to Home Depot I saw they had a different one than they usually carry, it had "Hole Dozer" on it, so I had no choice and bought it.

Turns out it is Milwaukee's new version that is supposed to last 2X longer and run 50% cooler. I tried it and it IS better. It also has a bigger clean out hole on the side, and the plug dropped right out. I am going to go through my cabinet and replace all the dull ones with these.........I really liked it.

Don

 

They're not slugs, they're fender washers!

 

I use hole saws drilling axels on the drill press, slow speeds and cutting oils. I did 2 axels with one hole saw. So if you don't abuse them they can last.

 

Yeah I just seen the Blair style ones but daaaaaaang the price.I'm just selling my die to buy one that cuts and dimples in one shot

 

The trick is your using a drill press. The stuff I'm dimpling cant fit in a press.like bomber seats,door panels that don't come off,my welded on visor,big interior sheets

 

I agree that WD 40 is about the worst lube you can use for cutting. I use thread cutting oil if I have it, if not then auto trans fluid. U have hole saws that have cut more holes than I can remember and still going strong.

 

I bought a Lennox arbor a while ago and I like their hole saws.
The general formula for tool RPM is: RPM = (cutting speed x 4)/tool diameter. So a the RPM for a 2" hole saw in mild steel is: (100 x 4)/2, which comes to 200 RPM. Excessive speed is what kills the hole saw. I use a spray bottle with water-soluble coolant to wash the chips away.

 

I was a machinist and also ran a toolroom for many years, bought a lot of holesaws, what I noticed a lot; guys would let the (new) holesaw "dwell" instead of just going for it, saws (larger dia.) like pressure more than RPM, saw a lot of guys take a brand new holesaw and touch the part and engage the power feed, the dwell time (as well as the grade of material) will take out the sharp teeth every time.
I'm a firm believer in using (the correct) cutting fluid in most cutting operations but as someone mentioned in an earlier post; holesaws do cut pretty well dry, as long as they don't get overheated.

 

Rotabroaches are absolutely the best option for cutting holes. They outperform any hole saws in every way.

 

Yeah well i don't have the exact right perfect cutting fluid..WD 40 is what I had.everyones getting hung up on that.

 

That's because we know its not right, its not good and we seem to be able to get more than 1 hole done. If I had a few holes to cut and only had WD40, I'd to the store and go get the right ****.
It probably is a big part of your problem.

Who posted the thread?
HOLE SAWS KEEP DULLING.HOW TO CUT HOLES IN METAL

 

I've heard a lot of folks don't use any lube.actually on this very thread its been posted.its done now so..

 

This always worked for me. Slow speed and a backup support (wood). Lots of cutting oil.

 

I've used rotabroaches at work.they do work well but...I don't have a mag drill and its hard to use that on a visor that's part of the car.I mean has any one cut holes in a visor? Its not that easy considering the angle and such.


Don't need the negative comment

 

Did you try it dry ?

 

You can get roabroach for hand drills too.

 

Tried it dry with an Irvin then wet,then motor oil (which someone did suggest) then tried a lenox,then a Milwaukee which suuuuuucked the worst.then another lenox.

It has to do with the angle I think.I cut two holes in a sheet metal intake an hour ago with a hole saw and it was fine.was able to do it flat and it cut okay. Not perfect but okay

 

If you are acknowledging using the wrong cutting oil; I agree with you.
The wrong lube can be worse than not using any at all.

 

Was it not said that one person said its better than nothing....geezz...this isn't a cutting oil thread

 

After struggling through most of my build with hole saws (even though I have successfully made lots of holes) I recently borrowed a friends set of the Blair Rotabroaches.

Wow, what the hell was I doing ?
They are expensive and worth every penny.
They cut a smooth accurate in size and clean hole.
Actually I could probably have bought them by now with all of the hole saws I have dulled and tossed. They are not cheap themselves.
I'll be getting a large set with all the sizes as soon as possible.

 

I bought most of my hole saws used at an auction, mostly Milwaukee, years ago. I've been abusing them up until last year on a drill press that only goes down to 400 RPM. Last year I got a small bench mill and they work much better (and quieter). I use cutting oil from the plumbing dept. at my favorite home store. I think I've only thrown one away.

Gary

 

We rarely use cutting oil because of the mess it makes. I realize it probably extends the life of the hole saw, but that is a trade off I am willing to make.

Don

 

Bacon Grease is what old time smiths and machinist used . Make Breakfast then get to work. Just don't let the pets lick it up.

 

So I got a hole flare tool now that punches too.end of story right? Did 3 hole sand the bolt striped and so did the die.I'm about tired of this

 

Well **** the bed man.
Have you tried a different tooth count on the hole saws?

 

Did you oil it before use?

 

You can buy water suluble cutting lubicant, then it is easy to cleanup Rotabroach is absolutely hands down the best hole cutter made.

 

i bought a set and bought individually.find out the maximum/rpm for the bit u are using in the material you are drilling.use cutting fluid.take your time andtake a break if you need one.