Drilling square holes

[Brett Nelson]

Alright guys, here I go on another aspect of my finish carpentry. Took me an entire month to finish all the trim work in the house. 6-piece built-up crown, coffered ceilings, wall frames, shadow boxes, etc.... Wheeewwww... I'm tired!!

Now I'm moving on to finishing the cabinets and the railings. It is the railings that I'm hung up on. American Cherry, over-the-post rail with 5/8" iron knuckle style ballusters, and 2 1/8" steel rope newels. I didn't have the option of getting the iron ballusters with the round dowel on the top, so now I have the problem of trying to fit a "square peg in a round hole". LITERALLY

Was looking into getting a 5/8" mortising chisel bit and just drilling square holes out for the ballusters on my drill press, but I've never used those bits before. Are they stand alone bits, or do I need to get a mortising jig for the drill press? I'm not looking to cut a long rectangular mortise, but rather just a 5/8"X5/8" square hole.

Also, do you think I should get the 3/4" bit instead, so the holes don't end up too tight?

[Lee Schierer]

The chisels have to be mounted in the holder and the drill turns the bit inside. They aren't that hard to use if your drill press has the morticing attachment. If you already have round holes you might be able to drive in the square chisel with a mallet to remove the corner material.

Another way would be to get a corner chisel and square up the round holes.http://images.rockler.com/rockler/images/92058-01-200.jpg
or the neander way with a hand chisel. http://images.rockler.com/rockler/images/47951-01-200.jpg

[Mike Cutler]

Brett

5/8" is actually a fairly good sized mortise bit. It's going to take some power to run that if the wood is hard. I don't think I would try to use a drill press mortising adapter. I would go with a dedicated Mortise press personally.

That chisel and bit set will need to be very sharp. Lee Valley sells an excellent honing cone and lapping plate for the chisel,and I would think about having a small diamond file to dress the end of that bit,and the leading edge.

I wouldn't go any larger than absolutely necessary,and 1/8" over size is too much. Stick with the 5/8" and use newly purchased, fine, 3/8" square file, or a set of riffler files to tune the opening.

This job could also be done with a router using templates. Waste the holes with you current drill press, use a 1/4" straight bit to make a nice square, and do the corners with either files, or by tapping the 5/8" mortising chisel through the hole. This way you could possibly use what you currently have on hand. If you have a lot of them to to do though, a mortising machine may be a nice investment at this time.

It sounds like an interesting project.

[Brett Nelson]

Oh... so how is the mortising machine better than just getting a mortising attachment for my current drill press?

[Mike Cutler]

Oh... so how is the mortising machine better than just getting a mortising attachment for my current drill press?

The dedicated mortising machine is a more rigid platform. While a small benchtop model is essentially a drill press of sorts. The design of even the smaller benchtop units is more rigid due to the use of a very wide "way", and an extremely rigid frame. The lever that is on the a dedicated mortiser allows for much greater leverage than can be had on a standard drill press,unless you have a pretty heavy duty DP that is more a mill/drill than a drill press.
The mortising attachment for the drill press may have some "slop" in it, which can result in movement while mortising. In the case of your project it may not be as apparent as mortising a series of holes, since you need to just mortise a single 5/8" at each location.
At times during the use of a DP mounted mortising attachment I've had to stop and realign it. I now use a Delta benchtop mortiser and there is no realignment once the fence is locked and the chisel and bit made square.

In the case of a floor standing mortiser there is no comparison. The integrated XY sliding table and vise, along with the substantial increase in weight, and greater position of leverage, allows for very quick accurate relocation of the material. A benchtop unit can also be re-fitted with an XY sliding vise too make it quicker and easier to reposition/relocate the material.

[David Schindeldecker]

For a few holes I believe the drill press will work fine. You will need the mortising attachment . . . the attachment holds the chisel as the dp chuck spins the bit inside it. You would also need to hold the stock down to the dp table to get the set out, as well. I morticed over 40 pairs of openings for the slats in my sons maple crib... never a problem on my dp. Take your time, and make sure your bit is below your chisel... the bit does the work, not the chisel.

The honing cone for keeping the chisel sharp is a GREAT suggestion. Mine's from Rockler.

I actually have 2 Delta morticing attachments. I went to get a new chisel size . . and the entire attachment set was on clearance at the BORG w 4 chisel sizes. It was cheaper than one individual bit . . ! No Duh .

[Russ Boyd]

Or you could go with the shoes (and drill round holes) that are made for this exact reason. They also give you great flexibility. You need to epoxy or (my favorite) polyurethane adhesive the balusters to the rail and plate or you will get some rattle when the wood shrinks and expands. The shoes are made for every application including the rake on the stairs. Check it out. Just google wrought iron balusters. Good luck, that's one of my favorite styles of railing. Russ

[Brett Nelson]

Or you could go with the shoes (and drill round holes) that are made for this exact reason. They also give you great flexibility. You need to epoxy or (my favorite) polyurethane adhesive the balusters to the rail and plate or you will get some rattle when the wood shrinks. The shoes are made for every application including the rake on the stairs. Check it out. Just google wrought iron balusters. Good luck, that's one of my favorite styles of railing. Russ

Yeah, I'm using shoes at the base of the ballusters, but not at the handrail. That gets a bit chunky for me. The railing profile is pretty dainty, and I think 5/8" ballusters with knuckles in the middle and shoes on both top and bottom would kinda overpower it.

[Russ Boyd]

Yeah, I'm using shoes at the base of the ballusters, but not at the handrail. That gets a bit chunky for me. The railing profile is pretty dainty, and I think 5/8" ballusters with knuckles in the middle and shoes on both top and bottom would kinda overpower it.
Then try this. It worked for me the one time I tried it. Drill the hole the size of the square (1/2"?) then use a rubber mallet to drive the rail onto the ballusters, thus making the hole square.

[Brett Nelson]

Then try this. It worked for me the one time I tried it. Drill the hole the size of the square (1/2"?) then use a rubber mallet to drive the rail onto the ballusters, thus making the hole square.

Yeah, I've heard of that, but the fittings are $100 each, and if I happen to break one then I've lost as much as I would've spend just buying a bench top mortiser. Seems a little bit "penny wise; pound foolish".

[Mark P. Brown]

Using a router cut the hole square but at each corner extend the cut at a 45 degee angle about 1/16 inch. No chisle work required.
Mark

[Brett Nelson]

Using a router cut the hole square but at each corner extend the cut at a 45 degee angle about 1/16 inch. No chisle work required.
Mark

That's some difficult router work. I've never tried to rout a piece that is held at a 35* angle before. Simply buying a $200 bench top mortiser isn't a problem.

[Prashun Patel]

Alright guys, here I go on another aspect of my finish carpentry. Took me an entire month to finish all the trim work in the house. 6-piece built-up crown, coffered ceilings, wall frames, shadow boxes, etc.... Wheeewwww... I'm tired!!

If there are no pictures, it didn't happen..... Post em high!

[Josiah Bartlett]

I'm not sure a benchtop mortiser is going to handle a 5/8" chisel very well, mine gets pretty hard to operate with 1/2" in hardwood, even when sharpened. However, you could use a 1/4" chisel to form the corners and then drill the rest out with a round bit, or you could just neanderthal the thing. with a rasp or a mortise chisel.

One thing to watch out for is that wood and iron expand and contract at very different rates. You may end up with split wood or loose iron after a few years when your holes change size.

[Terry Brogan]

Gently tapping the ballusters into round holes at the top that are just slightly undersized, with epoxy of the five-minute set variety, as thick as you can get away with (System 3 has some powder thickener) works fine. Same deal at bottom. Set all the ballusters into the rail, upside down, first, then just before they harden, flip the rail and set the bottoms. They don't budge after that. No need for the shoes at the top. Just blue-tape the balluster in case you have a little leakage. If you want more open time, get the longer-set epoxy.