drilling big holes

[Ralph Boumenot]

Hi
I'm thinking of building a new workbench and putting in a wooden vise and screw. The required hole for the screw is 2 5/8" and the cheapest bit I can find that big is about $130. Wee bit more then I want to spend. Is there some way to make this hole with out shelling out so much money for the one time I would use this drill bit?
thanx
ralph

[Mark Dorman]

Look for Irwin® Drill Press Adjustable Wood Bit, or expansion bit. Way less than 130 more like under 40 bucks. Practice on a test board first so you know what to expect.Mark

[Bruce Haugen]

sent a pm with a reference

[Ralph Boumenot]

thanx Mark, I'll google it and see if it will work. Still in the planning stages and I want to line up my ducks and get them all quacking as one.
ralph

[Jack Curtis]

I would saw it out rough then use a smallish spokeshave to smooth it. Alternatively, you could make the opening oversized square, into which you could insert a separate square, which could be cut apart for shaping a hole in the center.

[Derek Cohen]

Hi
I'm thinking of building a new workbench and putting in a wooden vise and screw. The required hole for the screw is 2 5/8" and the cheapest bit I can find that big is about $130. Wee bit more then I want to spend. Is there some way to make this hole with out shelling out so much money for the one time I would use this drill bit?
thanx
ralph

Hi Ralph

Draw the circle (2 5/8").
Now drill a series of adjacent holes inside the perimeter. I would use a 1/4" bit to get them closer together.
Chisel/rasp out the waste.

Regards from Perth

Derek

[Zach Dillinger]

Hi Ralph

Draw the circle (2 5/8").
Now drill a series of adjacent holes inside the perimeter. I would use a 1/4" bit to get them closer together.
Chisel/rasp out the waste.

Regards from Perth

Derek


This would be my choice.

Zach

[Jim Matthews]

+1 on roughing out the larger hole.

I mounted two recessed 2" nuts in my Moxxon vise just this way.
This could be cleaned up with a router in a circle template if you wish to avoid handwork.
(I would do it by hand, that way you won't likely overshoot your desired dimension.)

[Jessica Pierce-LaRose]

Drill a few holes and paring to fit is what Chris Schwarz shows in the workbench book, although I think he started with larger holes than the 1/4" derek recommended.

What about a holesaw? Probably have to drill down a bit, knock out some waste with chisel, and repeat, to get through the thickness of the leg. The larger sizes can be a bit pricey if you're buying fancy, but you might be able to find someone with a set and borrow one, as they're pretty common.

[Sean Hughto]

Um, here is one for less than $30. Many other brands are on the market that may be slightly more, but are far under $130.

http://www.grizzly.com/products/Large-Saw-Toothed-Forstner-Bit-2-5-8-/G1828

[Jerome Hanby]

Look for Irwin® Drill Press Adjustable Wood Bit, or expansion bit. Way less than 130 more like under 40 bucks. Practice on a test board first so you know what to expect.Mark

I bought one of those a while back for some long forgotten purpose that I never fulfilled <g>. How well does it work?

[Mark Dorman]

As long as there is something for the center of the bit to grab it's not bad. You want a backer board to keep from having blowout.
If you drill a hole then want to go bigger it won't work.

Mark

[Jan Weiner]

I haven't had much luck getting clean holes with the expansion bit and would definitely recommend the hole saw. They are about $15 at the borg including the mandrel. For another $10 there are extensions to reach the depth you will need. I used a #2 philips to snap the waste from the hole as the hole saw hit bottom. If you are looking for a clean exit on the inside of the leg, just use a long 1/4" bit to drill the pilot before starting, and then drill through from both sides. Definitely use a drill with a pigtail. Batteries just don't have the power to drill that size hole.

[James Owen]

Heresy that it is -- on this forum :D -- if you have a drill press and the work pieces will fit on it, a circle cutter might also work.

[Jessica Pierce-LaRose]

I actually use holesaws in my brace quite frequently - I've a little setup for drilling holes in some jar lids my wife makes into soap dispensers - ( I should really get a punch for that thin metal but I don't even know where to start with that ) and also for chassis holes in aluminum plate for things larger than I want to use my step bit or twist bits for. They work quite well, but the thing to beware of (and the same thing goes for step bits) on these with two jaw chucks is that while a round or hex bit will work okay in a tightly grabbing chuck (my yankee drill does particularly well with round bits compared to my other braces) is that a lot of the arbors for holesaws aren't actually hex shaped - they just have three flats ground on them. This works find in a three jaw chuck, but for a two jaw chuck, it means that there aren't actually two parallel sides anywhere on the bit - even if you can get the chuck to grab the bit, it's going to be horribly off-centered and unusable. Just something to keep in mind.

[Eddie Darby]

Even less expensive are the LV Forstner bits.




2-5/8"


06J01.42


http://www.leevalley.com/US/images/item/bulletins/diamondch.jpg


$19.10




http://www.leevalley.com/US/wood/page.aspx?p=63611&cat=1,180,42240

[Greg Portland]

Hi
I'm thinking of building a new workbench and putting in a wooden vise and screw. The required hole for the screw is 2 5/8" and the cheapest bit I can find that big is about $130. Wee bit more then I want to spend. Is there some way to make this hole with out shelling out so much money for the one time I would use this drill bit?
thanx
ralph
MLCS, Steelex, and others sell 2"+ Forstner bits for < $30 (Amazon, etc.). The shank may not be long enough so use one of these: http://www.amazon.com/Grizzly-H5943-Drill-Bit-Extender/dp/B0007D2BUM

[george wilson]

I don't like expansion bits. In the 60's I had a Woodcraft expansion bit,which at that time,and from that source,probably better quality than most of those today(especially the Irwin). It would get loose and keep expanding in the hole,in spite of being fully tightened. The hole would get bigger inside.

If you get the Grizzly,and it isn't HSS,use a VERY slow speed on the drill press. Carbon steel will heat up and lose temper.

Probably best to drill a bunch of holes,as suggested,and then rasp it out. OR, if you get the Grizzly bit,drill all around the circumference with smaller drills,retaining the solid center of the wood. Then,with the slowest speed,drill the hole out with the large bit. The drilled small homes will make the job a LOT easier for the large(probably carbon) drill.

In fact,you could also drill holes within the circumference to further relieve the big drill from turning blue. Just save the center of the hole for the center spur of the large drill to stabilize itself on.

For trying to drill from the solid wood,without relieving the circumference as explained above,I expect the drill press doesn't go slow enough. If I had to bore that hole,I'd put it in my lathe,and run it 30 RPM. Most drill presses just do not go slow enough. Not even the metal versions,unless they are VERY expensive. I have seen usually,metal drill presses that advertise that they'll drill a 1 1/2" hole in cast iron. But,with a low speed of 150 RPM,that will just burn out the drill bit.

[Andrae Covington]

Hi
I'm thinking of building a new workbench and putting in a wooden vise and screw. The required hole for the screw is 2 5/8" and the cheapest bit I can find that big is about $130. Wee bit more then I want to spend. Is there some way to make this hole with out shelling out so much money for the one time I would use this drill bit?
thanx
ralph

I bought and used the LV sawtooth forstner bits that Eddie Darby linked to. I bought the cheaper HCS ones for the larger sizes I figured I'd rarely if ever use again, and HSS for some smaller ones that I needed. I borrowed the use of a friend's drill press and set the belt to the slowest speed possible. Still kinda scary fast, and the vibration would periodically loosen the morse taper on the chuck.:( (Mind you this was a nice, new-ish drill press.)

I also did some shallow counterbores with a fly cutter on the drill press (to inset the vise garters, 5" diameter), and that was horrifyingly fast even at the slowest speed.:eek: Not recommended, even for Normites.

The sawtooth bits, once chucked up, were not quite long enough to bore all the way through the leg. So I finished the vise screw hole with a hole saw in a brace drill. It's not as smooth as using a drill press, unless you're exceptionally steady as you swing your arm around. So the walls of the hole are not so pretty, but it works, and the fear factor is quite low.

[Bill Haumann]

I recently did this for a leg vise with an Irwin expansion bit and brace. It quickly gave way to roughing the hole with smaller augers once I realized that since I wasn't tapping the hole, it did not need to be a perfect (or even close) circle.

[Jessica Pierce-LaRose]

FWIW, I was just looking at Chris Schwarz' workbench book again and looking at the section for his slab-top cherry bench - for the vise chop, he drills a series of larger holes, and cleans them up with a chisel for a roughly sized hexagonal hole, but in the leg, he just makes a big ol' honking square hole.

[Jessica Pierce-LaRose]

Since I brought up a holesaw, and since I needed a hole for the Lake Erie screw I just ordered today, I thought I'd have a go with it. Probably not the best method, but I figured it wasn't the worst, so I'd have a go at it.

The big holesaw in my cheap drill press was scary, so I went with a brace, as I mentioned.

225896

Layed things out first, finding my center point. I went with a height that will put my bench screw 10 inches down from the top of the bench, as that was what I saw in a couple of plans in the Chris Schwarz's workbench book. Scribed a circle with my dividers to allow me to make sure I wasn't way off when the hole saw came into play.

225897

I used my cheap drill press to drill a hole for the lead drill of the hole saw, this should help me a little bit to guide the hole saw square through the full thickness of the leg. My drill press (nor the bit I was using) have enough length to get through the whole leg, and even if it did, there's enough runout in this silly thing to be a problem, so I drilled from each side.

225898

The holes lined up pretty darn near perfect.

225899

Not bad for this rusty thing I think I bought out of the back of a truck.

225900

My Yankee 8" brace. It's got the best jaws out of my braces for holding these round-shank bits. Because a hole-saw means you aren't removing a whole lot of waste, I can get by with the 8" sweep. If I was ripping up the whole width with an auger, I'd want to use something with a much larger sweep!

225901

A little paste wax on the sides of the bit helps a little if things start binding . . .

225902

Also remember, this kerf fills with sawdust pretty quickly, since you aren't drilling through a board, but just keep going . . . and going . . . so I stop pretty frequently to clean up the sawdust with my little shop vac.

A key point to remember, I find, is the "saw" part in "hole saw" - you can push harder, but it's not going to saw much faster. Let the weight of the tool do the work. Also, a lot of times, with the cheap holesaws, (particularly if you've been drilling stuff like drywall or plaster, which is pretty abrasive) the things aren't that sharp. You can sharpen these carefully with a small file, and things go a lot better. I should have stopped to sharpen this before this job, and I'm regretting I didn't.

225903

Working with a longish chisel (well, you don't need to start long, but you need a long one as things get deeper) and going across the grain, you can knock out pretty big chips as you go along. This Witherby socket chisel I usually use for more delicate work, but it got the job done. Remember, unlike a mortise, there's no going back and doing the final cuts afterwards, so be careful when you lever not to bruise things.


More to come . . ..

[Jessica Pierce-LaRose]

225906

225905

Getting there . . .
225904

Like I said . . . big chunks. No need to be delicate.

225907

Because speed, not torque really seems to be the key here, I tried switching to this little 6" Stanley/Fray brace for the other side. (Switching sides, again, seems to help on keeping things squarish. It was a little faster because of the smaller swing, but I found it harder to keep level for whatever reason, and the chuck didn't do as good a job as the Yankee on the round shank bit. That 8" Yankee seemed to be the sweet spot for me.

By the way, if you're trying to figure out why the bit is slipping, it's probably something in the whole hole saw assembly - in my case, the set screw on the drill shank loosened somehow, and it took me a while to figure out what was going on.

225908

I couldn't chisel out the last bit - but the more you chisel away, the closer easier going it is, if for nothing else than the sawdust can get out of the resulting shallower kerf easier. Here's what was left when I was done.

225909

A little hair between the two cuts, but they don't seem too far off from each other.

225910

And a nice, pretty perfect looking hole. Granted, one that you really won't ever see, but a really nice hole nonetheless. A perfect clearance fit at 2 and half inches and

wait? 2 and a half inches? Wasn't this going to be a clearance fit at a hair larger than 2 and a half?


225911

Yeah - make sure you have the right hole saw chucked up *before* you start drilling.

Darn it.

[Jessica Pierce-LaRose]

225912

In the end, it looks pretty nice, although I'm going to have to open it up and ruin that look, but like I said, you're not going to see it.

Speed? I should have time it. Too slow, but having worked with these things before, I've got a feeling it's because I should have sharpened the holesaw first. I don't know why I didn't. I also wasted a lot of time fiddling with that set screw. Still probably would have been faster to drill a series of holes and then whack out the waste, either roughly, or done a series of quarter inch holes like Derek recommended.

So yeah? The holesaw thing I mentioned? Probably not worth it, but it looks okay in the end. For a hole you really won't ever see. But it was cheap. But so is drilling a few more holes and knocking things out with a chisel.

Strikes me that the drill press in these photos is the first use of a powered tool on this "bench" build. Also, I have a lot more respect now for folks like Derek who can get something done *and* take nice photos of it in the progress. Also makes me realize I need better lighting in the work room.

[Ralph Boumenot]

Hi Derek,
I actually thought of doing this but I was hoping that there was something easy. That said, I found my fly cutter and I'm going to experiment with that this weekend.
ralph

[Ralph Boumenot]

Hi Sean,
I didn't think of Grizzly and they don't come up on a google. For $30 I might go that route.
ralph

[Ralph Boumenot]

Thanks to all the great info I got. Nothing like the collective brain power of Neanderthal Haven to solve problems. I think I'll go with drilling a bunch of holes around the perimeter and using chisels and rasps to clean it up. I can use the $30 plus on wood.
ralph