Chopping Mortises

[Nathan Johnson]

I'm currently working on my bench and chopping mortises for the stretchers in the legs. Using laminated SPF 2x4s and a 12mm bevel edge chisel.
I do not own any mortise chisels. No drill press. No auger bits. So I'm asking for any tips on chopping better mortises.
The chisel is square, with a 25 degree primary bevel and an approximately 30 degree micro bevel.
I seem to wander a bit as I go, and my walls are a bit out of square. Is this just a matter of getting better with practice, or are there any tricks or techniques that are greatly beneficial?

Thanks.

[Hasin Haroon]

Hey Nathan,

Here's a tip that helped me a lot. Mark out all four sides of your mortise with a marking gauge and knife, and then use your knife to score all four sides deeply. Use a chisel the exact same size (or if you can't, smaller) to peel out the wood in between the marks. If you scored them deeply, in pine, you should have around 1/16 to 1/8 shallow 'mortise' that you can now use to register your chisel for all the cuts you'll be making. It'll give you much cleaner side walls compared to the inevitable variation in chisel placement that happens when you're cutting your first mortises. I've seen this method used in a number of places, such as Derek's website.

A lot of folks prefer drilling out the mortise and then finishing up with a chisel but I find that cumbersome and less accurate. The best way (for me) is to size my mortise exactly the width of the chisel I'll be using and chop away.

[Nathan Johnson]

Hey Nathan,

Here's a tip that helped me a lot. Mark out all four sides of your mortise with a marking gauge and knife, and then use your knife to score all four sides deeply. Use a chisel the exact same size (or if you can't, smaller) to peel out the wood in between the marks. If you scored them deeply, in pine, you should have around 1/16 to 1/8 shallow 'mortise' that you can now use to register your chisel for all the cuts you'll be making. It'll give you much cleaner side walls compared to the inevitable variation in chisel placement that happens when you're cutting your first mortises.

A lot of folks prefer drilling out the mortise and then finishing up with a chisel but I find that cumbersome and less accurate. The best way (for me) is to size my mortise exactly the width of the chisel I'll be using and chop away.

Thanks. I am using a mortise gauge (well, the Veritas dual marking gauge) set to the width of the chisel I'm using, but just using the gauge lines. I'll try making those deeper and see if that helps.

[Chet R Parks]

Hi Nathan,
Along with what Hasin said I use 1/8 thick x 1 or 1.5 inch aluminum angle to register the chisel against to maintain a vertical wall. Being an angle ii's easy to clamp to the board. I have several different lengths of angle and use the length appropriate for the board. Good luck with your project.
Chet

[Nicholas Lawrence]

Paul Sellers has a Youtube video on chopping mortises. I found it very helpful, and for whatever reason when I do it that way they end up square.

[Nathan Johnson]

Hi Nathan,
Along with what Hasin said I use 1/8 thick x 1 or 1.5 inch aluminum angle to register the chisel against to maintain a vertical wall. Being an angle ii's easy to clamp to the board. I have several different lengths of angle and use the length appropriate for the board. Good luck with your project.
Chet

Good tip, I can try that. Thanks.


Paul Sellers has a Youtube video on chopping mortises. I found it very helpful, and for whatever reason when I do it that way they end up square.

Yes, his method is what I am trying to emulate. Sure looks easy when he does it.

[David Eisenhauer]

Sounds like these may be your first or at least "firster" mortises and , if so, yes it will get better as you gain experience. In my opinion, the Paul Sellers demo is one very definite way to chop them with good results. Work bench frame mortises are usually large and deep, so the joint will be solid if some small area of the entire mortise is slightly out of plumb due to minor undercutting. I run a small square along the side and end walls of the mortise to check for any "bulges" that will prevent the tennon from sliding in and tend to skip using a square guide to hold my chisel against because I don't have too much trouble ending up plumb. Certainly a wider chisel helps create a more consistent sidewall, but the 1/2" - 12mm size chisel is probably my most used paring chisel. If the wood is hard, a 35* micro bevel may be better, but that is for you to decide. If the $ is available, maybe order a wider chisel for use here and to add to the collection. Also, I don't tend to pound the chisel for maximum penetration when chopping, but just bop it a couple of whacks to take what the chisel gives me. That tends to keep my chisel better in square than when I try to go for deeper penetration by pounding harder.

[Robert Engel]

A guide block will be of great help to you.

Its not hard to ruin a bevel edge chisel chopping mortises. A firmer chisel will be more expeditious. Any fairly decent utility chisel will do, then use your bevel edge to fine tune the sides in conjuction with the guide block.

[lowell holmes]

I attended Homestead Heritage when Paul Sellers was there, we learned to chop mortises with bevel edge chisels.
You just don't pry out large chips. Try it, it works. I have mortise chisels and use them, but occasionally on a small
mortise, I will use a bevel edge chisel, especially on 1/4" mortises.

[Simon MacGowen]

Pay attention to these three things, too:

- take care to place the chisel so the cutting edge is right inside the scribed lines when you start, Close enough is not good enough as long as either edge corner cuts outside a line
- chop perpendicularly which is easier said than done unless you position yourself properly so can see you are chopping plumb. Practice and have someone stand in front to tell you if you are indeed chopping plumb. Thinking that you are plumb with the chisel does not cut it. Set up a mirror if no one can help you.
- when you pry, make sure you pry straight and not slanted, but parallel to the walls. Key word: take it slow till your muscle memory takes over.

If you rush before you are good at it, you are bound to get crappy or bruised mortises. Gappy joint? Don't listen to the videos where you see the guy fill the gap with sawdust. It does not work and will only fool a non-woodworker. Once you apply a finish to the piece, the fix will pop up.

Mortise and tenon is a good joint for using your chopping as well as sawing skills. Worth the time to become very very good at it. Remember: mortises first, though I have seen books showing cutting the tenons first.

Simon

[Nathan Johnson]

Sounds like these may be your first or at least "firster" mortises and , if so, yes it will get better as you gain experience. In my opinion, the Paul Sellers demo is one very definite way to chop them with good results. Work bench frame mortises are usually large and deep, so the joint will be solid if some small area of the entire mortise is slightly out of plumb due to minor undercutting. I run a small square along the side and end walls of the mortise to check for any "bulges" that will prevent the tennon from sliding in and tend to skip using a square guide to hold my chisel against because I don't have too much trouble ending up plumb. Certainly a wider chisel helps create a more consistent sidewall, but the 1/2" - 12mm size chisel is probably my most used paring chisel. If the wood is hard, a 35* micro bevel may be better, but that is for you to decide. If the $ is available, maybe order a wider chisel for use here and to add to the collection. Also, I don't tend to pound the chisel for maximum penetration when chopping, but just bop it a couple of whacks to take what the chisel gives me. That tends to keep my chisel better in square than when I try to go for deeper penetration by pounding harder.

Thanks for the detailed reply.
Yes, these are my first mortises, other than testing on a couple of scrap pieces. I'm brand new to woodworking really, and this bench is my first project.
12mm was the closest I could get to making the tenons 1/3 the width of the stretchers. I might try playing with the bevel angle...

[Nathan Johnson]

Pay attention to these three things, too:

- take care to place the chisel so the cutting edge is right inside the scribed lines when you start, Close enough is not good enough as long as either edge corner cuts outside a line
- chop perpendicularly which is easier said than done unless you position yourself properly so can see you are chopping plumb. Practice and have someone stand in front to tell you if you are indeed chopping plumb. Thinking that you are plumb with the chisel does not cut it. Set up a mirror if no one can help you.
- when you pry, make sure you pry straight and not slanted, but parallel to the walls. Key word: take it slow till your muscle memory takes over.

If you rush before you are good at it, you are bound to get crappy or bruised mortises. Gappy joint? Don't listen to the videos where you see the guy fill the gap with sawdust. It does not work and will only fool a non-woodworker. Once you apply a finish to the piece, the fix will pop up.

Mortise and tenon is a good joint for using your chopping as well as sawing skills. Worth the time to become very very good at it. Remember: mortises first, though I have seen books showing cutting the tenons first.

Simon

Thank you. And apologies for my cantankerous replies the other day.
The mirror idea is good.
And yes, I am cutting the mortises first and then fitting the tenons.

[Simon MacGowen]

[QUOTE=Nathan Johnson;2716368]Thank you./QUOTE]

No hard feelings at all as we all are just trying to put our points across. Once a thread is over, any disagreements are over too.

Good luck with your mortise & tenon attempt. It really is a cornerstone of furniture joint. In some ways, it (through m.t.) is more demanding that a through dovetail joint.

Simon

[ken hatch]

Sounds like these may be your first or at least "firster" mortises and , if so, yes it will get better as you gain experience. In my opinion, the Paul Sellers demo is one very definite way to chop them with good results. Work bench frame mortises are usually large and deep, so the joint will be solid if some small area of the entire mortise is slightly out of plumb due to minor undercutting. I run a small square along the side and end walls of the mortise to check for any "bulges" that will prevent the tennon from sliding in and tend to skip using a square guide to hold my chisel against because I don't have too much trouble ending up plumb. Certainly a wider chisel helps create a more consistent sidewall, but the 1/2" - 12mm size chisel is probably my most used paring chisel. If the wood is hard, a 35* micro bevel may be better, but that is for you to decide. If the $ is available, maybe order a wider chisel for use here and to add to the collection. Also, I don't tend to pound the chisel for maximum penetration when chopping, but just bop it a couple of whacks to take what the chisel gives me. That tends to keep my chisel better in square than when I try to go for deeper penetration by pounding harder.

David,

The best advice of the bunch. This is a case of slower is faster, less is more. Bench or pig sticker it should be tap, tap, lever, tap, tap, lever, repeat till finished. Going Conan makes for a bad mortise and will slow the process.

ken

[Jim Koepke]

Just to echo what others are saying, it is like learning many tasks in life, work toward accuracy and speed will come naturally with time.

jtk

[Joe A Faulkner]

It is not critical for your mortises for your stretchers in your bench to be a perfect tight fit for the tenons. So don't sweat it if the tenons are not square. If you draw ore the joints you will get a strong, sturdy joint.

[Nathan Johnson]

I'll just say it's a good thing the apron is going to hide my first one. Yikes.

[David Eisenhauer]

Work your way around the table and then re look at the first one. It should be OK, especially if you are drawboring them (good idea) as Joe says. If you are really still unsatisfied with the first one, you can trim the mortise out a little to clean it up and then glue a thin shim on the tennon (on the correct side) and slowly skin the fat side of the tennon down to the correct thickness. That can be done with a chisel, router plane, shoulder plane, flat rasp or saw if you can hold it to the line. Plane shavings (curls) make especially good tennon shims for minor increment changes or you can glue up an over fat shim to the side of the tennon and then recut it with a saw and start all over with that side.

[Brian Holcombe]

On big mortises I cut them differently than I cut small mortises. I generally cut mortises right to the line, but large through mortises I often cut in from the line then pare toward it. I Don't leave a lot, just 1/32" or so on either side so that I can tune the fit.

[steven c newman]

Have tried the bevel chisel routine.....have an 8mm from Aldis.

Biggest thing I do is do the tenons first. then trace around the tenon to mark out the mortise....I try to leave those lines.

Chopping is a matter of tap, move, tap, move. One whack of the mallet/hammer, move the chisel forward a bit, and whack again. After a couple, clear the chips. This will leave room for the bevel to push the chips out of the way. When you get to one end, make sure the chisel stays vertical, no leaning allowed. Do not wiggle the chisel side to side, either. Clear the chips, and repeat....doesn't take all that long. Do a dry fit to check on the fit, and the depth.

Clear chips by laying the bevel down. push the chisel a bit to raise the chips right out. No need to pry.

[Patrick Chase]

Paul Sellers has a Youtube video on chopping mortises. I found it very helpful, and for whatever reason when I do it that way they end up square.

I don't use Sellars' technique, but it's probably worth noting that he demonstrates chopping mortises with a bench chisel, which is exactly what the OP needs. IMO there are more efficient ways to go about it if you used pigstickers.

[steven c newman]

IF you had any, of course....

[Nathan Johnson]

I'm sure I'll end up with mortise chisels eventually, but yeah, for now I just have the bevel edge.
I've got the first four chopped and the tenons cut to fit. Certainly not perfect, but number four is markedly better than the first one was.

I guess the good news is my sawing is better than my chopping. Really liking these Japanese saws.

[Patrick Chase]

I'm sure I'll end up with mortise chisels eventually, but yeah, for now I just have the bevel edge.
I've got the first four chopped and the tenons cut to fit. Certainly not perfect, but number four is markedly better than the first one was.

It's a surprisingly fast learning curve to get to where you can produce perfectly usable results. What isn't so easy to develop is speed. People who've been doing it for a very long time can bash out a good mortise in a minute or so, where it would take somebody like me significantly longer.

The Sellars video is here (https://www.youtube.com/watch?v=q_NXq7_TILA). It's important to keep in mind that the "end-in" technique he uses is reasonable for a bench chisel, but IMO not optimal for a pigsticker. His failure to adapt his technique to each type of chisel is probably why he finds the bench chisel to be faster :-).

[Simon MacGowen]

The Sellars video is here (https://www.youtube.com/watch?v=q_NXq7_TILA). It's important to keep in mind that the "end-in" technique he uses is reasonable for a bench chisel, but IMO not optimal for a pigsticker. His failure to adapt his technique to each type of chisel is probably why he finds the bench chisel to be faster :-).

It should also be noted that because the plastic guard worked as a guide for placing the chisel, Paul could chop and pry out the waste relatively quicker. Without the guard, he would have spent a bit more time each time he raised the chisel and re-placed it on the mortise.

I have seen his perfectly clean mortise & tenon work and so I am sure he did the video in a less careful way just for demo purposes, because I don't like the way he pried the last bits of bottom waste with the mortise chisel, bruising the ends of the finished lip. In other clips, he was a lot more careful in the prying.

Simon

[Patrick Chase]

I have seen his perfectly clean mortise & tenon work and so I am sure he did the video in a less careful way just for demo purposes, because I don't like the way he pried the last bits of bottom waste with the mortise chisel, bruising the ends of the finished lip. In other clips, he was a lot more careful in the prying.


Even if you could get the bottom perfectly "clean" it wouldn't matter, because the glue joint between it and the end of the tenon is end-to-long grain and therefore quite weak. Basically all of the strength of an M&T comes from the long-to-long grain interfaces between the cheeks.

To be clear, I have no concerns about the mortises Sellars produced in that video. My critique was that the pigsticker would have been faster if he'd taken the time to optimize his technique for it.

[Simon MacGowen]

I mean clean lips, not the bottom.

[Patrick Chase]

I mean clean lips, not the bottom.

Maybe he was going to put tiny matching haunches on the tenon :-)

Seriously, most of the time the end lips don't impact structural integrity either, though obviously they will if they meet a shoulder-less tenon face. I've seen people with far more skill than I rapidly bash out mortises with rather ugly ends and bottoms, but immaculate cheeks. IMO they're onto something :-).

[Nathan Johnson]

Taking smaller bites and paying closer attention to chip removal helped a lot on this last one. They seem to be getting incrementally better, although I'm painfully slow and working on sawhorses is killing my back.
5 down, 3 to go.

[Warren Mickley]

Both the bevelled edges of your chisel and the secondary bevel on the edge make for instability and sloppy mortises. You can make mortises with a chisel like yours, but it isn't as easy. In the long run you will want a mortise gauge, set to the width of the chisel and used to mark both timbers, and a mortise chisel with a flat bevel.

Since you are working on saw horses, I recommend sitting on the piece you are mortising. This will keep the piece steadier and be better for your back.

[Brian Holcombe]

I agree with Warren, and I apologize I scanned the OP quickly and assumed since this is a bench-building topic that we were talking about much larger mortises. 12mm is best done as Warren describes above.

I have mortise gauges set to the exact size of my mortise chisels for that same reason. I have also found sitting on the piece to help significantly with mortising.

[Patrick Chase]

I have also found sitting on the piece to help significantly with mortising.

I gave that a try last night after seeing your post and Warren's, and I see the benefit. Among other things it's easier to eyeball and maintain vertical from that position. Thank you Brian and Warren.

[Pat Barry]

I gave that a try last night after seeing your post and Warren's, and I see the benefit. Among other things it's easier to eyeball and maintain vertical from that position. Thank you Brian and Warren.
Just make sure the board you are working with is long enough and wide enough or you could be in a painful situation. :)

[lowell holmes]

Why buy pig stickers if you don't have to have them?

Of course, many of us including me, have to have one of each tool.:)

I will go for months not buying anything, and then see something and . . . . . .............

[Kevin Perez]

My critique was that the pigsticker would have been faster if he'd taken the time to optimize his technique for it.

Just curious--what is the optimized technique for using a pigsticker for a mortise? (I just use Seller's technique with bevel edge chisels in furniture and have had good results. But, I'm not adverse to "having" to buy a better/ another tool...)

[steven c newman]

There is no "optimize' with a pig-sticker chisel.......brute force is what they are all about. Maybe one could try such a chisel when chopping dovetails?

[Brian Holcombe]

I disagree, finesse is useful in chopping mortises.

[ken hatch]

There is no "optimize' with a pig-sticker chisel.......brute force is what they are all about. Maybe one could try such a chisel when chopping dovetails?

Sorry but that is Bull. The design is optimized for chopping mortises, not for brute force. All pounding on a EOBMC will do is slow you down and make a mess of the mortise.

ken

[ken hatch]

Just curious--what is the optimized technique for using a pigsticker for a mortise? (I just use Seller's technique with bevel edge chisels in furniture and have had good results. But, I'm not adverse to "having" to buy a better/ another tool...)

Kevin,

Not much different from any other chisel. Controlled taps on the chisel stopping when the chisel tells you to stop or slightly before and having space to lever the waste. Of all the factors space to lever the waste with out excessive effort is most important. Going Conan on either the tapping of the chisel or levering is slowing and counter productive as well as likely to damage the walls of the mortise.

ken

[steven c newman]

366082
My usual tool kit....
366083
Results in Curly Maple.

[Patrick Chase]

I disagree, finesse is useful in chopping mortises.

I agree with this.



Not much different from any other chisel. Controlled taps on the chisel stopping when the chisel tells you to stop or slightly before and having space to lever the waste. Of all the factors space to lever the waste with out excessive effort is most important.

The part about having space to lever out the waste is key as Ken says, and is also where Sellars' technique was non-optimal. In the video (https://www.youtube.com/watch?v=q_NXq7_TILA) he starts at one end and simultaneously works down and towards the other end, which is what I meant when I described it as "end-in" technique. IMO he develops an initial bottom profile that is overly "steep" (i.e. each sequence of cuts forms a very acute "V" shape) and lacks space for waste clearance.

Simultaneously working away from the center of the mortise in both directions works better for me, because the resulting "V" profile is much shallower. There are at least two other ways to achieve adequate waste clearance that I know of, and probably more, but that's the one that works for me.

[steven c newman]

Used to be a series of videos from GE Hong......maybe some people should watch them again? He does show a few ways to chop a mortise....and does it FAST. He is still moving the chisel when he start the next swing...and never misses. Look it up, sometime when you get bored....

25 videos on Youtube.....look up "Traditional Chinese Woodworking"

[Nathan Johnson]

I agree with this.



The part about having space to lever out the waste is key as Ken says, and is also where Sellars' technique was non-optimal. In the video (https://www.youtube.com/watch?v=q_NXq7_TILA) he starts at one end and simultaneously works down and towards the other end, which is what I meant when I described it as "end-in" technique. IMO he develops an initial bottom profile that is overly "steep" (i.e. each sequence of cuts forms a very acute "V" shape) and lacks space for waste clearance.

Simultaneously working away from the center of the mortise in both directions works better for me, because the resulting "V" profile is much shallower. There are at least two other ways to achieve adequate waste clearance that I know of, and probably more, but that's the one that works for me.

Maybe this is a stupid question, but I haven't tried it so....would starting in the center work fine with a bevel edge chisel also?

[Brian Holcombe]

It should work fine.

Mortise chisels offer a genuine advantage in that they're shaped in a way that self jigs once the cut begins to be established. Bench chisels can work fine but I feel the process is overly harsh toward them at certain stages of the work.

[Nathan Johnson]

Really appreciate all the suggestions here.
Two things have helped a lot:
1. Sitting on the workpiece.
2. I switched from my Narex chisel to my Aldi chisel, and it seems to wander much less as I strike it. Thicker sides? I'm not sure, but I can tell the behavior is different.

[Jim Koepke]

I switched from my Narex chisel to my Aldi chisel, and it seems to wander much less as I strike it. Thicker sides? I'm not sure, but I can tell the behavior is different.

Different chisel designs will react differently when used in different methods of work. That is only one reason there are so many different types of chisels.

jtk

[Patrick Chase]

Maybe this is a stupid question, but I haven't tried it so....would starting in the center work fine with a bevel edge chisel also?

Yes, but space for waste clearance typically isn't as critical with bevel-edge chisels because of their lower profile, so they aren't as sensitive to which technique you use.

[Kees Heiden]

I agree with this.



The part about having space to lever out the waste is key as Ken says, and is also where Sellars' technique was non-optimal. In the video (https://www.youtube.com/watch?v=q_NXq7_TILA) he starts at one end and simultaneously works down and towards the other end, which is what I meant when I described it as "end-in" technique. IMO he develops an initial bottom profile that is overly "steep" (i.e. each sequence of cuts forms a very acute "V" shape) and lacks space for waste clearance.

Simultaneously working away from the center of the mortise in both directions works better for me, because the resulting "V" profile is much shallower. There are at least two other ways to achieve adequate waste clearance that I know of, and probably more, but that's the one that works for me.

Not sure about that Patrick. The 'Sellers' technique has the benefit of reaching depth much quiker. And it saves the effort of turning around the chisel on each cut. In the end I think it hardly matters and you could become just as quick with both methods if you practice enough.

[lowell holmes]

I'm sure I'll end up with mortise chisels eventually, but yeah, for now I just have the bevel edge.
I've got the first four chopped and the tenons cut to fit. Certainly not perfect, but number four is markedly better than the first one was.

I guess the good news is my sawing is better than my chopping. Really liking these Japanese saws.
Well, get nice tenon saw, maybe Lie Nielsen or Lee Valley.

[Kevin Perez]

Well, get nice tenon saw, maybe Lie Nielsen or Lee Valley.

I have one of each and can definitely concur with Lowell's comment. Both seem to work equally well. The LV appealed to my wallet, but the LN appeals to my soul (with the gorgeous materials and classical lines). That said, I went through a Japanese tool phase and really liked the saws. I still use them for rough work, though there's no reason I couldn't use them for fine work, too.

[Nathan Johnson]

I have a Lee Valley dovetail saw, and a couple of older tenon saws.
Then I have a Ryoba and Dozuki.
I'm still new, and learning, but so far I prefer the Japanese. I have a seriously messed up right shoulder and the Japenese are definitely easier on my shoulder.
Still experimenting though.

[Mark Stutz]

I'm little late to the show, but just don't make the same mistake that I made. My first mortices were drilled out, but I cleaned them up with a chisel and a RUBBER mallet!

[Nathan Johnson]

I'm little late to the show, but just don't make the same mistake that I made. My first mortices were drilled out, but I cleaned them up with a chisel and a RUBBER mallet!

How do you sharpen a rubber mallet?





:D

[lowell holmes]

Beat on the pointed end of the chisel.

[Mark Stutz]

How do you sharpen a rubber mallet?





:D

Frequently!;)


Beat on the pointed end of the chisel.

It was almost that bad. The said chisels were Marples blue chip right out of the box. New chisels should be sharp. Right?:D

[Patrick Chase]

It was almost that bad. The said chisels were Marples blue chip right out of the box. New chisels should be sharp. Right?:D

It takes a confident and secure individual to admit to that on SMC :-)

IMO the loss of knowledge and traditional training opportunities almost guarantees that we all start out doing stupid sh*t. I certainly did (and still do).

[Mark Stutz]

Not really! I don't post in a lot of these threads because so many here have more experience and knowledge. I just try to keep people from making the same mistakes I did.

The little computer desk that I built, however, is still rock solid!:D

[David Eisenhauer]

Alls well that ends well Mark. Good on you for the rock solid computer desk. In an uncertain world, at best, it does not get much better than a solid build project. Photos please.

[Mark Stutz]

Really surprised I even still had any! From a long time ago, back in the day when little plastic discs called compact discs, CD for short were used to store electronic data!:D


Alls well that ends well Mark. Good on you for the rock solid computer desk. In an uncertain world, at best, it does not get much better than a solid build project. Photos please.366707366706