Hole saw recs?
- Thread starter MEDTECH
- Start date
timgunn1962
Well-known member
For mdf and wood, pretty much any bimetal blade will get the job done.
Don't run too fast and stop regularly to clear the dust from the teeth. The dust can build up enough to stop them cutting and start to scorch. If you smell burning, stop immediately and check/clear the teeth.
Looking to the future, I'd suggest going for one of the "standard" dual-pin drive arbors and the size of holesaw you need initially. That gives the widest choice when you come to add to your system.
There are a few useful things to be aware of.
As mentioned above, drilling a 1/4" pilot hole first means that a piece of 1/4" drill rod, ideally with a flat ground on it for the clamping screw to bear on, can be used instead of the pilot drill. This can give a neater hole, particularly in steel: the potential problem that this helps avoid is that the holesaw is not presented at exactly 90 degrees to the surface, the first tooth to touch grabs and causes the pilot drill to chew into the side of the pilot hole, enlarging it. The pilot doesn't work well because it is running in an oversized hole, everything flails around and you end up with an oversized hole. A holesaw isn't a precision tool at the best of times, but I've had to deal with holes that are a good 1/8" oversized because they've been made by someone inexperienced who didn't realize things were not going as they should.
If you need a disc without a hole in the middle, you can holesaw a hole in a piece of scrap, clamp the scrap to the workpiece, remove the pilot drill and holesaw a disk using the hole in the scrap as an external pilot. I tend to use 1/2" mdf scrap. This also works well if you need a slightly more precise hole than you'd normally expect from a holesaw, though it's obviously a bit more hassle to locate than just running the pilot through at the hole center location.
At some point, you'll need to enlarge a hole. You can either use the scrap trick above, of you can use a "rework adapter" like the starrett bc891. This replaces the pilot drill takes a holesaw the size of the original hole to provide the pilot location for the bigger holesaw.
Don't run too fast and stop regularly to clear the dust from the teeth. The dust can build up enough to stop them cutting and start to scorch. If you smell burning, stop immediately and check/clear the teeth.
Looking to the future, I'd suggest going for one of the "standard" dual-pin drive arbors and the size of holesaw you need initially. That gives the widest choice when you come to add to your system.
There are a few useful things to be aware of.
As mentioned above, drilling a 1/4" pilot hole first means that a piece of 1/4" drill rod, ideally with a flat ground on it for the clamping screw to bear on, can be used instead of the pilot drill. This can give a neater hole, particularly in steel: the potential problem that this helps avoid is that the holesaw is not presented at exactly 90 degrees to the surface, the first tooth to touch grabs and causes the pilot drill to chew into the side of the pilot hole, enlarging it. The pilot doesn't work well because it is running in an oversized hole, everything flails around and you end up with an oversized hole. A holesaw isn't a precision tool at the best of times, but I've had to deal with holes that are a good 1/8" oversized because they've been made by someone inexperienced who didn't realize things were not going as they should.
If you need a disc without a hole in the middle, you can holesaw a hole in a piece of scrap, clamp the scrap to the workpiece, remove the pilot drill and holesaw a disk using the hole in the scrap as an external pilot. I tend to use 1/2" mdf scrap. This also works well if you need a slightly more precise hole than you'd normally expect from a holesaw, though it's obviously a bit more hassle to locate than just running the pilot through at the hole center location.
At some point, you'll need to enlarge a hole. You can either use the scrap trick above, of you can use a "rework adapter" like the starrett bc891. This replaces the pilot drill takes a holesaw the size of the original hole to provide the pilot location for the bigger holesaw.
Thanks, again for the recs. The larger hole on the right is what I just drilled out. The hole on the left was done using a spade bit. Very smooth and , surprisingly, no blowout. Took about 10 seconds.
Will use the smaller hole for the speaker wire and larger for AC cord to keep them isolated.
micromind
Well-known member
Here's how I drill wood that's horizontal, like a desktop;
1) Drill a 1/4" hole in the center using a basic standard 1/4" bit
2) Using the holesaw, cut a circle about 1/8" deep.
3) Drill one or more 1/4" holes in this circle. This will allow the sawdust from the holesaw to fall down rather than build up in the hole saw teeth.
Thanks, again for the recs. The larger hole on the right is what I just drilled out. The hole on the left was done using a spade bit. Very smooth and , surprisingly, no blowout. Took about 10 seconds.
Will use the smaller hole for the speaker wire and larger for AC cord to keep them isolated.
My OCD is killing me that they're not on the same horizontal plane...
Seriously... Glad you got it done AND acquired a new tool. You'll end up using it more than you think.
Glad to hear the hip is doing it well. Yep, it's easy to get used to being off work. I had surgery in 2021 and thought I'd be off a couple of weeks. Doc said it would be 8 weeks off! I really enjoyed that! Ended up retiring 3 months after I returned to work. I'm REALLY enjoying that!
I have to second Diablo. I bought a set of milwaukees and several of them are so malformed as to make the hole a size larger. I've started swapping those sizes out with Diablo and the difference is night and day.I use these (hole saws) a lot.
I second Milwaukee's good products, but I have switched to Diablo basically exclusively. I use Freud blades also almost exclusively in my woodworking, and Bosch owns the companies, so there are no issues there.
Some (not many) are made in the US, but most of their manufacturing is still in Italy if that sort of thing matters to you.
I have about thirty of these, I included pictures of two I happened to be using. They have a quick-release system compatible with the rest of the industry, and there are easy eject ports for getting your material out of the "hole" of the blade itself.
Normally, the off-plane would drive me nuts, too. The reason why I did that was to keep the power cord from coming near the speaker wire. The speakers back panel kinda dictated where. Plus, the speaker will hide that panel. Normally, tho, I would measure and drill in a clean way. I'm OCD, as well.My OCD is killing me that they're not on the same horizontal plane...
Seriously... Glad you got it done AND acquired a new tool. You'll end up using it more than you think.
Glad to hear the hip is doing it well. Yep, it's easy to get used to being off work. I had surgery in 2021 and thought I'd be off a couple of weeks. Doc said it would be 8 weeks off! I really enjoyed that! Ended up retiring 3 months after I returned to work. I'm REALLY enjoying that!
Glad you're enjoying retirement; I probably have 9 years, give or take. Luckily, I am keeping myself pretty busy with minor tasks and reorganizing...but, I'm not missing work as much as I thought I would.
MichaelP
Well-known member
Almost all (if not all) grommets sold on Amazon require 50mm hole. 2" hole saw will create a slightly larger hole, so you'll need to either buy a 50mm saw or be prepared to shim the grommet or glue it in. Otherwise, it'll be loose.
With this being garage journal, I'm a little disappointed nobody suggested that you need a full 60 piece metric/SAE set of high end forester bits to drill the holes. 
For what it's worth, I've got four decent hole saw sets, one cheaper Hurcules, one Milwaukee and two styles of Spyder along with various single sizes of different brands up to 6" for different projects.
By far my favorite are the Spyder. All of them function just fine for most projects, but I really love the Spyder for deep holes through multiple layers because they clear the removed material so easily.
For what it's worth, I've got four decent hole saw sets, one cheaper Hurcules, one Milwaukee and two styles of Spyder along with various single sizes of different brands up to 6" for different projects.
By far my favorite are the Spyder. All of them function just fine for most projects, but I really love the Spyder for deep holes through multiple layers because they clear the removed material so easily.
MichaelP
Well-known member
Chinese manufacturers make them in metric, but name in the closest SAE figure. So whether they call it 50mm or 2", it is 50mm. 
rlitman
Well-known member
Yeah, I've noticed that the ones I've bought in the last few years fit looser than they did going further back. That totally explains it. I just put on a few wraps of tape to improve the fit.Chinese manufacturers make them in metric, but name in the closest SAE figure. So whether they call it 50mm or 2", it is 50mm.
MichaelP
Well-known member
This was the reason, I just bought a separate 50mm hole saw to prevent headaches when installing those grommets occasionally.
In the past, 2" grommets required 2" hole saw.
In the past, 2" grommets required 2" hole saw.
mellowdave
Active member
Most folks don't need (or even know about) the precision that real woodworking tools provide. I agree with your assessment on the Milwaukee, and if you need a hole that's "pretty much about that size" they're fine, and durable.
tulowd
Well-known member
You haven't lived until you cut a 6" hole thru the carpet, plastic and metal of a 70s era American car door in one shot with a 1/2" 120V corded old school Metabo or Makita drill. We used to do this frequently at the car audio shop I worked at in the 80s. Barbarism, excitement and danger all at once, especially if the customer was witnessing this. No safety glasses or gloves, naturally.
I have around 25 hole saws now, they are all Milwaukee or Craftsman (which are interchangeable on the arbor) bi metal. Anything not bi metal is likely to get dull and become really dangerous too. The bi metal ones will cut stainless sinks in case you plan on adding a soap dispenser or glass sprayer. I also grabbed a few diamond/carbide grit holesaws that are pretty awesome; I've used them on wood (not so good), carbon fiber (with a respirator!) and some other materials, I think they're likely best for unknown obstructions, cause they will cut anything incl I believe concrete.
Holesaws with powerful drills are easily capable of breaking your wrist and then attacking your project and possibly you if something jams/binds, which is pretty easy on larger diameters.
I cut a lot of large dia holes into mdf for loudspeakers. If the hole saw is too small, the jig saw and then router table are used to finish.Drill a 1/8" pilot hole using a drill guide to ensure the hole is perfectly square and true.
Then drill the aforementioned 1/4" hole solo; then have at it with the holesaw. Keeping the speed appropriate will mitigate jamming and burning; it's a good idea to pull it up to allow the cut/dust to escape.
If you have no need for, or want to save the money, using an orbital jigsaw with a proper Bosch or similar high end blade made for the material (likely melamine on particleboard) is not too difficult, as long as there is blade clearance below, Also, a router can do this, only the mess will be biblical.
Tape up the surface in any event with painters tape and mark out the hole you are after. Jigsaw will cut a hole that small, you can finish with router or hand sanding if the OCD is high enough.
Good luck and be careful; pls share photos of the ongoing effort and the final product pls.
I have around 25 hole saws now, they are all Milwaukee or Craftsman (which are interchangeable on the arbor) bi metal. Anything not bi metal is likely to get dull and become really dangerous too. The bi metal ones will cut stainless sinks in case you plan on adding a soap dispenser or glass sprayer. I also grabbed a few diamond/carbide grit holesaws that are pretty awesome; I've used them on wood (not so good), carbon fiber (with a respirator!) and some other materials, I think they're likely best for unknown obstructions, cause they will cut anything incl I believe concrete.
Holesaws with powerful drills are easily capable of breaking your wrist and then attacking your project and possibly you if something jams/binds, which is pretty easy on larger diameters.
I cut a lot of large dia holes into mdf for loudspeakers. If the hole saw is too small, the jig saw and then router table are used to finish.Drill a 1/8" pilot hole using a drill guide to ensure the hole is perfectly square and true.
Then drill the aforementioned 1/4" hole solo; then have at it with the holesaw. Keeping the speed appropriate will mitigate jamming and burning; it's a good idea to pull it up to allow the cut/dust to escape.
If you have no need for, or want to save the money, using an orbital jigsaw with a proper Bosch or similar high end blade made for the material (likely melamine on particleboard) is not too difficult, as long as there is blade clearance below, Also, a router can do this, only the mess will be biblical.
Tape up the surface in any event with painters tape and mark out the hole you are after. Jigsaw will cut a hole that small, you can finish with router or hand sanding if the OCD is high enough.
Good luck and be careful; pls share photos of the ongoing effort and the final product pls.
That probably explains it. I'm not a woodworker at all. I'm a metal guy, so maybe I'm just expecting too much from my woodworking tools. I also acknowledge that a hole saw of this type is not intended to be a precision tool, even as woodworking tools go. That said, it's hard to ignore when I see the same issues over and over with their construction. I made a quick vide to demonstrate what I'm talking about.
PowerWagonBuilder
Well-known member
I'm a fan of the Milwaukee and Lenox saws but don't have experience with the Diablos saws. I stopped buying their stuff after ending up with poor performing 8" carbide metal saw blades when compared to the life of the Evolution or Milwaukee brands. It seems that my older Milwaukee saws have less of the offset issues than the newer "hole dozer" ones.
One thing I am surprised to not see mentioned, or if it was I missed it, is for cutting thicker materials, the use of an internally tangent chip hole. When cutting downward, hole saws like to pack full. Annular cutters have external flutes for clearing chips vs holesaws typically don't. This causes the teeth to get packed full, which creates a lot of recutting and especially with metal, heat and increased cutting force.
If I am cutting anything that is thicker than the tooth depth of a saw, I try to pre-drill a chip clearing hole, or two even, that is just inside the edge of the hole to allow the chips to fall out of the way and the cutting goes much faster and the saws last so much longer.
Here is one I knocked out this past weekend with some A36 mild steel. 1-1/4" thick with a 2-5/8" Diameter saw. The final hole needs to be 2.72" diameter and as mentioned in this thread, the saws are not precision but do a good job of clearing the way. Yes, those dimensions are accurate despite the weird scale created by the Jacobs chuck partially visible. Thats a 1/4" chip clearing hole but I should have gone a little bigger on this depth of cut as the chips did pack up on me twice so I stopped and cleaned them out. I ended up using a boring head to finish the bore to final size.
The saw has plenty of life and was already a "used" condition. I have 3 more of these holes to bore in the same material and parts.
Just a bi-metal saw, turned at 90 rpm and fed by hand. Used some tap magic as I went.
One thing I am surprised to not see mentioned, or if it was I missed it, is for cutting thicker materials, the use of an internally tangent chip hole. When cutting downward, hole saws like to pack full. Annular cutters have external flutes for clearing chips vs holesaws typically don't. This causes the teeth to get packed full, which creates a lot of recutting and especially with metal, heat and increased cutting force.
If I am cutting anything that is thicker than the tooth depth of a saw, I try to pre-drill a chip clearing hole, or two even, that is just inside the edge of the hole to allow the chips to fall out of the way and the cutting goes much faster and the saws last so much longer.
Here is one I knocked out this past weekend with some A36 mild steel. 1-1/4" thick with a 2-5/8" Diameter saw. The final hole needs to be 2.72" diameter and as mentioned in this thread, the saws are not precision but do a good job of clearing the way. Yes, those dimensions are accurate despite the weird scale created by the Jacobs chuck partially visible. Thats a 1/4" chip clearing hole but I should have gone a little bigger on this depth of cut as the chips did pack up on me twice so I stopped and cleaned them out. I ended up using a boring head to finish the bore to final size.
The saw has plenty of life and was already a "used" condition. I have 3 more of these holes to bore in the same material and parts.
Just a bi-metal saw, turned at 90 rpm and fed by hand. Used some tap magic as I went.