Thread: How Do I Improve My Mortise Chisel Technique?

Why do you want a "router quality finish"? The tenon does not care. As long as it is a good, even fit ...

Regards from Perth

Derek

Hi Helmut,

Derek has got it.. so long as the fit is reasonably ok, and not too tight, it doesn't matter what it looks like inside, a bit of roughness doesn't matter.

The most important thing is that the shoulders of the tenon pull up neat and tight. Cut the mortise a little deeper to get the shoulders snug.

Regards
Ray

Going by the two responses its seems like I am expecting to much.

Yes surface finish does not matter in real world terms. The shoulders do. But that is no problem

I have learned to be finicky. The fact remains that the better the mating surface the better the glue joint. Any voids and discrepancies between the two faces will create a weak spot, since most glues form poor adhesion across voids. In an ideal world we would be able to plane all and every face inside and out.

What about the difference the width of the mortise and the chisel? Also is 5 small mortises the limit of this tool between sharpening.

If you are really concerned about the holding power, then draw bore the joint.

http://www.inthewoodshop.com/Furniture/Drawboring.html

What about the difference the width of the mortise and the chisel? Also is 5 small mortises the limit of this tool between sharpening.

The width of the mortice and the chisel should be the same. They are marked at the same time with the same cutting gauge.



http://www.inthewoodshop.com/Furnitu...ndMortice.html

Five small mortices? I guess that depends on the hardness of the wood and what you define as "small".

You said that you were using an LN mortice chisel. As I recall this is has a 30 degree primary bevel and a 35 degree secondary bevel. These are sash mortice chisels and not a heavy-duty type. An oval bolstered mortice chisel (pigsticker) is traditionally given a 20 degree primary bevel (for deeper penetration) and a substantial 35 degree secondary bevel (for strength). These are larger, heavier duty chisels and can remove the waste pretty quickly. Still, your LN should do a very good job.

1 - The chisels is 3/16" (4.7625 mm) now the mortise however came out at around 5.1 mm. What am I doing wrong or is this normal? A 0.45 mm is a large enough discrepancy to make the productions of tenon problematic due to irregularities in the mortise. With a router I cut a 4 mm mortice, I make a 4 mm tenon and have a 0.0 mm difference. Any discrepancy means individual adjustment of tenons, slowing down the production process.

I suspect that you are not chiseling straight. Perhapsthe chisel is not sharp enough?

I like to first pare out the surface of the mortice. This makes it easier to keep the first deep strikes in line with the edges.





This defines the mortice and makes it easier to keep it all straight and square.


Regards from Perth

Derek

Hi Helmut,

Assuming that the LN is A2...
I've heard anecdotal evidence that brand new A2 blades sometimes suffer from chipping, but settle down once you get past that layer. I can't find any references just now, but I'd persevere and see if it gets better... what about a group production run of socket mortice chisels? Know any good suppliers of M2 bar stock?

As for the width of the mortise, a mortising chisel should register on the sides nicely, it might just be technique, keeping the chisel vertical and so on. I'm sure there are others here who can offer better advice than I can.

Regards
Ray

Originally Posted by RayG

Hi Helmut,

... what about a group production run of socket mortice chisels? Know any good suppliers of M2 bar stock?

As for the width of the mortise, a mortising chisel should register on the sides nicely, it might just be technique, keeping the chisel vertical and so on. I'm sure there are others here who can offer better advice than I can.

Regards
Ray

Hi Ray

I made a few smaller mortice chisels to square the ends of grooves and router-made mortices. These used HSS section from McJing.



http://www.inthewoodshop.com/ShopMad...ngChisels.html

They work very well for smaller mortices as well. Nevertheless I would not give up my pigstickers, which are trapazoid-sided.

Regards from Perth

Derek

Ciao,
I think is very difficult to reach the precision of routers by hand as well as the inside surface smoothness. So, apart to pay attention to the correct use of mortice chisels and setting-out, I use to cut the mortice with the line and the tenon just outside the line. Then a block rabbet plane help me for a fast fine fitting.

Giuliano

Ts , I've moved almost exclusively to what Wouldwood calls, horse sauce or hide glue as it seems to deal with voids in the joint far better than white glues.
X-rays I've seen of fine furniture in restoration seems to show greater space within the mortice an a looser tenon than I would expect. I suspect the idea of a piston fit joint is actually counterproductive to joint strength/efficiency as the joint may be starved of glue in many places . The rough sides may infect help key the surfaces together, similar to when we key a surface before laying veneer
The idea of a perfect internal surface of a joint is
probably more of a hang over from being taught by perversly sadistic woodwork teachers in high school.(maybe that last bit is just me .....?)
Cheers

Ian

The main thing we were taught when chopping mortices was to stand in line with the work so you could make sure you were holding the chisel vertically. Leaning a bit towards you or away didn't really matter of course as long as you weren't chopping from the ends. Once you've got enough depth you can square the ends.
Cheers,
Jim

Thumbsucker,

In one of David Charlesworth's videos he chops a mortice sitting on a stool and references an engineer's square behind to ensure the chisel is vertical.
His eyeline is almost at mortice level which means he gets the full height of the square against the full length of the chisel blade, I think this is much easier than trying to line it up from above ie standing. He demonstrates this method for width accuracy and also the end wall of the mortice where he either shifts his seat or the timber around 90 degrees (cant remember which one).

Cheers,

Sam

Originally Posted by RayG

Assuming that the LN is A2...
I've heard anecdotal evidence that brand new A2 blades sometimes suffer from chipping, but settle down once you get past that layer.

This is one of my suspicions and hope it will improve.

Originally Posted by RayG

what about a group production run of socket mortice chisels? Know any good suppliers of M2 bar stock?

Why do you think I bought this tool. I wanted to learn about it. Before proposing it, also lots of blokes are keen on something like this.

Originally Posted by ac445ab

So, apart to pay attention to the correct use of mortice chisels and setting-out, I use to cut the mortice with the line and the tenon just outside the line. Then a block rabbet plane help me for a fast fine fitting.

A technique I have come to love is using the table router to face my tenons. Getting micrometer accuracy with perfectly square tenons. I have used a borrowed LN block rabbet plane and its a great tool for exactly this job. So this is an easy sale.

Originally Posted by jimbur

The main thing we were taught when chopping mortices was to stand in line with the work so you could make sure you were holding the chisel vertically

I think this maybe my problem. I have been standing front on not end on to the mortise.

I found an article. This give different methods. However Schwarz says that the pre drill methods (Hayward) gives best interior mortises faces.

Sam - I use Charlesworth's method all the time for dovetails, i.e. sighting the chisel to a square sitting on the bench behind the workpiece. It really does work brilliantly.

As for mortise chisels, well there's always one of these

English Mortise Chisels by Ray Iles at Tools For Working Wood

D2 steel anyone??

HI TS

As Mr B suggests ..

... here is an aid to holding the chisel vertical.

I prefer to hold the stile over a leg of the bench using a handscrew. The handscrew is clamped to the bench with a long F-clamp. The shaft forms a handy sight for the mortice chisel.




I stand directly behind the chisel and in line with the red handle ..

(there is more here: http://www.inthewoodshop.com/Furnitu...ndMortice.html)

Regards from Perth

Derek

Good idea Derek - two birds with one stone and all that !

Interesting to read the blurb in the Ray Iles mortise chisel description concerning the shape of the chisel handle for mortise work. I can see that a round section handle would be less than ideal.