Looking for a tip to center my forster bit in my mortise

[Dick Snyder]

Unless this is a rather small item, consider making your mortises wider than your Forstner bit. As far as straight drilling goes, do you have a drill press that swivels to drill next to a good wood vise? It's hard to beat the accuracy of a well-mounted vise, and a little shimming will keep the wood in the right place for through drilling. If there are lots of pieces to be pierced, replace the stationary wood jaw with a customized one of the correct thickness.

For deep holes, an auger bit is nearly as accurate as a Forstner, and the chips clear easier. If you really want

1/4" mortise, consider an undersized (7/32"? ) brad point drill bit.

----------------- I am making 1/4" wide and 1/4" deep mortises in a leg that is 7/8" square. I can not move my drill press to a vise. Before I started this project I experimented with twist drills and brad point drills as well as forstner bits. Each was 1/4". I didn't try a smaller drill bit. That is actually a good idea as it leaves me totally in control of the edges of the mortise with my chisel. I am making a set of stacking tables. Each table has 4 legs (naturally) and each leg has 2 or 4 mortises. I am finishing up tenons tomorrow (I hope) on the first table. When I start the next set of legs I will experiment on some scrap with an undersized brad point bit to see how that works for doing my mortises. Thanks for the suggestion.

Dick

[Dick Snyder]

Before starting this project I thought about beadlock. I talked to the guys at the Rockler store and they weren't crazy about beadlock. I could never pin them down as to exactly what they didn't like and they even sell beadlock at their store. I assume you have had good experience with it since you suggested it.

[David G. Nagel]

I have used the beadlock system and I really can't recommend it. There are a lot of holes to drill with it and the locking knobs for the slide are a bitch to tighten down. I replaced them with a hex head bolt. Still they do a good job considering and if the need comes again I will use them.

Dave N

[Lew Hodgett]

I modified this design:

follows:

Hardware:

All Stainless steel

1/4-20 x 2" HEX head bolts, flat washers and wing nuts.

10-32 x 1/2" flat head machine screws to attach jig to router base.

Runners:

Maple 3/4 x 1-1/4 with 5/8" dia x 1/2" dp counterbore and 9/32' thru hole for hex head bolts.

I refuse to use carriage bolts, the the counterbored holes above.

Assemble a washer under head of bolt and insert into counter bore and snug up with another nut.

Pour epoxy fairing putty into counter bores a little proud and let cure 24 hours.

Table:

1/4" plywood rather than hard board.

Get some 16x16 grid graph paper and glue it to the plywood with contact cement of 3M spray 77.

Align the graph paper with a major grid line running down the long (major) centerline of the plywood.

Working from the graph paper side, layout the slots for the 1/4" bolts, 2" thru hole and your router base(Mine was a PC-90).

Using clear packing gun tape, cover the graph paper to seal and protect it.

Perform all machining operations including c'sinks from opposite side to accept router body mount screws.

Remove 1/4x20 hex nuts used to sung bolts previously, while epoxy cured.

Break any rough corners with some 150 grit, then seal all raw wood with 3-4 coats of 1/2lb shellac. (I get better results than with 1 coat of 2 lb).

Let cure a couple of days and have at it.

You may not have picked up on it yet, but using the graph paper to locate the 3/4 x 1-1/4 runners, you need no other layout tools to get dead nuts, repeatable mortises, piece after piece.

The only pencil layout required are the end lines for the mortises and you will be able to visibly see the cutter come in contact with the pencil line.

Have fun.

Lew

[Dick Snyder]

Thanks Lew. That is the same one that I made. I have printed out your mods and will study my version for application.

Dick

[Pat Barber]

Beadlock will work in a "drilling" situation.

I have one and it is used very little but it can do things no other jig can do very easily.

The Beadlock can do offset mortises very easily but the Beadlock requires some practice to very effective.

I "strongly" recommend going to a router for your mortising work.

Here are a couple of jigs:

another way to do m&t joinery at Swingman's jig that he built:

Dick Snyder wrote: