Hope the new jig helps

[Scott Clausen]

I am wanting to make a frame and panel door for of all things the access to the basement/crawlspace. I like to use a task that would do just fine with plywood and turn it into a skill builder. My first practice tenon is spot on but the mortice was a total fail. The mortice chisel wondered to one side a bit and while I can true the protruding side the other could not be saved. I re-watched Paul Sellers and noticed he made a jig to reference the side of the chisel to so it "may" stay true. I made my jig today and kept having this thought of these parts are small so what hand tool can get this done? Jig is built but in the end it was the low angle jack, manual miter saw, shooting board and the band saw made a cameo appearance. Band saw (hangs head) so ashamed. Just having fun, The more hand tool I do the more I like it.

[Jim Koepke]

The mortice chisel wondered to one side a bit

A few things can cause this.

Derek Cohen has demonstrated a method he uses with a clamp holding the piece being mortised. The clamp is set to be perfectly vertical and is used for aligning the chisel by eye.

If the edge on the chisel isn't square it can cause a chisel to wander.

Another problem can be caused by the bevel being at an angle from side to side causing the chisel to twist as it is driven.

You might also have a better result if you first drill out most of the waste.

For a simple process, there is a lot going on.

jtk

[Scott Clausen]

Thanks Jim,

The mortice chisel is square but I have sharpened it for the second attempt hopefully later today. I am pretty sure that it was me guessing that I am close enough to vertical to get the job done, I wasn't. For large mortices like my bench legs I do drill out the waste with brace and bit but this is a 3/8" mortice so it is kind of tight in there. I will try with my alignment block and if success eludes me I will try drilling and can still use my jig as a reference surface to pare down the side walls. One way or another I am going to get this. Thanks again

[Edward Weber]

I would also suggest drilling out the waste, at least as much as you're comfortable doing. Mortise chisels are designed to be hammered and cut end grain, which can be a difficult job. Drilling out and removing as much material as you can, leaves more room in the mortise for the chisel debris you cut away and makes it much easier to square off the corners.
Even on a power mortiser, the first cut is the most difficult. One there is more room for the waste to go and reduce the binding of the chisel, everything is easier.

[Charles Guest]

Watch the whole video:

https://www.youtube.com/watch?v=XhtD14Qn5pM

[steven c newman]

F&P Box Project, almost there.JPG
About the same way I fixed this...
F&P Box Project, ready to plane.JPG
Tenon vs groove..one was tilting a bit...

[Charles Guest]

I just clamp a piece of wood a few inches away from the joint and sight the chisel that way. I think Ian Kirby mentioned this in an article he did for FW decades ago. I don't particularly care for registering the side of the chisel to a jig, but it certainly would work.

Nothing new!

When my elbow is hurting (and that's a lot these days), I drill them out with a brace and use the same piece of wood to sight the brace and bit.

[Scott Clausen]

20210711_144026.jpg
20210711_144006.jpg
That seemed to be the ticket, one side is a bit off but that was because I mucked up the shoulder a little with a shoulder plane when I was trying to right the ship on the last attempt. I am happy enough to proceed with milling the styles and rails now.

[Jim Koepke]

Here is an alignment tool made for auger bits:

Auger Square Alignment Tool in Use.jpg

The base is a made so the dowels are at 90º to each other in relation to the bit. Something similar could possibly work to help keep a chisel aligned.

jtk

[Charles Guest]

Here is an alignment tool made for auger bits:

Auger Square Alignment Tool in Use.jpg

The base is a made so the dowels are at 90º to each other in relation to the bit. Something similar could possibly work to help keep a chisel aligned.

jtk

I appreciate that Jim. I've used a Stanley 59 for alignment but it was a little too slow. I'm still good with something to sight against, but I imagine my time will run out on that soon enough. My doctor says tri-focals or something like them are in my near future. Good excuse to start looking at power mortisers!

[ken hatch]

Here is an alignment tool made for auger bits:

Auger Square Alignment Tool in Use.jpg

The base is a made so the dowels are at 90º to each other in relation to the bit. Something similar could possibly work to help keep a chisel aligned.

jtk

Jim,

Clever, I can see something like your jig, with slight modification, helping with drilling leg mortises for chairs. Once I return to Tucson and the shop I will give it a go.

As to the OP, most of the problems with chopping mortises come from using too much force. Tap, tap and flick works much quicker and better than whack, whack and lever. About the only time drilling is better is when the mortise is wider than your chisel or the mortise is too deep and narrow.

ken