Sharpen a dull holesaw (YES it works!)

[Gofast]

I have used hole saws in metal up to 6in dia in my drill press and in metal 1in thick. I have managed to drill multiple holes with the same saw bit. The secert to getting life with a hole saw is to drill a hole just inside the cutting edge of the metal you wish to saw. This gives someplace for the chips to fall out of. Slow speed and generous cutting oil, not wd40.. Steady pressure so the bit will bite. Light pressure leads to more dust than chips. Also use a air nozzle to keep the chips blowed out. Chip build up is what dulls the saws, not cutting the metal.

I have been using used motor oil in a pump can to keep lubed up when drilling holes. I need to add using compressed air for the chips.

 

[Sodo]

This is a tip I need to remember for larger holes in steel.

The secret to getting life with a hole saw is to drill a hole just inside the cutting edge of the metal you wish to saw. This gives someplace for the chips to fall out of.......Chip build up is what dulls the saws.

 

[sodamo]

So has anyone sharpened a step drill bit? Seems mine get one or two dull spots.

 

[PILOON]

So has anyone sharpened a step drill bit? Seems mine get one or two dull spots.

Heck yes, but they sort of lose the pilot 'step' but still make holes.

Wait, are U referring to the carrot shaped multi bits?
or the drill bits that seem to have a small 'pilot' tip built in.

I'd assume the carrot type is could be dressed from the side of the slot but at the low cost, why bother.

What I have found on offshore sites is nice sets of carbide tipped 'bell type' hole saws (like a set of 5 up to ,75")
With some proper cutting oil I have drilled many 3/4" oils in up to 1/2" steel.
I consider them to be a 'must have' as a DIY guy so I ordered a second set, just in case, LOL.
They even have a spring to offload the slug but it fails early mainly due to heat and chips.
Usually +/- $10,/set of 5.

 

[chas0218]

when cutting a 2-1/2" hole horizontally to install a transfer switch, i cannot use lube or drill vertically. My holesaws were drilled at slow speed, but sometimes never made it thru one hole without dulling. the carbide bits dont seem to have that issue.

You beat me to it. I only buy carbide anymore. Granted not cheap but buy once cry once.

I also sharpen spade bits using a file, only a couple passes and she's ripping again. I also sharpend a couple of those speed bits by Irwin. Those speed bits really rip when doing holes for electrical.

 

[NewportNic]

I have even touched up carbide bits, using a small diamond wheel in my Dremel tool.

 

[lennyzx11]

Couple of tricks to add to the slow speed and just enough pressure.
I use tap magic cutting fluid and Milwaukee bimetallic saws.

Steal your wife’s sponge from the sink, cut a circle out of it to fit and stuff it in the hole saw. Dip in water before starting keeps the saw cool.

Before the saw breaks through but the pilot is sticking out. Go to the opposite side and drill from there. This eliminates breakout tearing in wood and a ragged edge in thin metal. Also the plug is sticking out of the saw when hole is completed making it easier to remove.

I’m going to try the sharpening trick and the hole to let the chips fall out of the way. Great stuff!

 

[inthe country]

If you ever find yourself with a burnt-up hole saw, a hole that need to be drilled and no way to sharpen or replace the saw, there is a trick you can use. Take a pair of end nips, needle nose pliers or similar tool, grab the edge of the saw and twist until it breaks. Move around the circumference of the saw doing the same thing. You will now have a saw that will cut. It won’t be a beautiful hole, but it will work in a pinch.

 

[Reb954]

If you ever find yourself with a burnt-up hole saw, a hole that need to be drilled and no way to sharpen or replace the saw, there is a trick you can use. Take a pair of end nips, needle nose pliers or similar tool, grab the edge of the saw and twist until it breaks. Move around the circumference of the saw doing the same thing. You will now have a saw that will cut. It won稚 be a beautiful hole, but it will work in a pinch.

Are you saying we should break off the saw teeth?

 

[inthe country]

Yes. It does work.