Hollow Chisel Mortiser vs. Horizontal Mortiser

[Rick Bradshaw]

Having a floor mounted hollow chisel mortiser was always on my bucket list. Now that I start looking I see they are not really widely available like they were 10 years ago or more. The PM is the only one I see and I am upset with PM because my splined handle bracket (cast) on my benchtop unit broke in two the other day and a replacement is not available.

I will start looking for a used one, but in the mean time I see that the horizontal mortisers seem to have taken on some popularity.

Does anyone know why the floor standing units seemed to have disappeared?

Anyone have any experience with the horizontal units?

Rick

[Mike Henderson]

I've used both and the horizontal slot mortiser is much easier and quicker to use. I have a Domino now so a slot mortiser is of less interest to me, but they can do more than a Domino can do - bigger/smaller, wider/deeper, etc.

Horizontal slot mortisers have been around forever, they're not just recent tools.

Mike

[Kevin Jenness]

Plenty of old iron hollow chisel mortisers to be had, good for making rectangular mortises in edges to be mated with integral tenons. Horizontal slot mortisers make round-ended mortises in edges or ends well suited to spline tenons and reinforcing cope and stick joints, easy to set up and versatile.

[Wes Grass]

There's a General 220 in CT, on Machinio. Drool worthy for sure.

[Jim Andrew]

Have you looked at the G0846? I would buy that one, but already have the G0540, which works fine for mortises as long as you don't need angles. Both are floor models.

[Jim Dwight]

I have never used a horizontal mortiser but I suspect they make nicer looking mortises like a router or domino. My hollow chisel (Jet benchtop) makes rougher mortises and is much more time consuming to setup and use than my domino XL. I make longer mortises with the domino by plunging repeatedly on about half inch intervals. It will cut mortises about 2 3/4 deep. The largest bit is 14mm (about 5/8). I really like the domino.

[Mike Henderson]

I have never used a horizontal mortiser but I suspect they make nicer looking mortises like a router or domino. My hollow chisel (Jet benchtop) makes rougher mortises and is much more time consuming to setup and use than my domino XL. I make longer mortises with the domino by plunging repeatedly on about half inch intervals. It will cut mortises about 2 3/4 deep. The largest bit is 14mm (about 5/8). I really like the domino.

I agree with Jim. A Domino is essentially a portable slot mortiser. I'd spend the money on a Domino before I'd purchase a horizontal slot mortiser. I have the smaller Domino and it's met my needs so far.

I use it to make mortises for standard M&T joints, not just for loose tenons.

Mike

[Andy D Jones]

I agree with Jim. A Domino is essentially a portable slot mortiser. I'd spend the money on a Domino before I'd purchase a horizontal slot mortiser. I have the smaller Domino and it's met my needs so far.

I use it to make mortises for standard M&T joints, not just for loose tenons.

Mike

Just out of curiosity, do you round the edges of the tenon, or square the ends of the mortise?

I like through tenons (tusked or not) so I'm looking at the PM 719T with tilt table. I like the idea of a tilted table better than a tilted head, motor, and perhaps more importantly, operating lever. I also have a project in mind that through mortises angled at 30 degrees (from perpendicular) which is within in the range of the 719T, but not of any of the tilt-head mortisers I've seen.

-- Andy - Arlington TX

[John TenEyck]

Unless you are making though tenons I see no reason to square the end of a mortise cut with a horizontal slot mortiser. So to answer your question, I round over the edges of the tenons when using integral tenons. Most of the time, however, I use loose tenons and I round over the edges of the tenon stock before cutting them to length. Much easier and more efficient for me.

John

[Mike Henderson]

Just out of curiosity, do you round the edges of the tenon, or square the ends of the mortise?

I like through tenons (tusked or not) so I'm looking at the PM 719T with tilt table. I like the idea of a tilted table better than a tilted head, motor, and perhaps more importantly, operating lever. I also have a project in mind that through mortises angled at 30 degrees (from perpendicular) which is within in the range of the 719T, but not of any of the tilt-head mortisers I've seen.

-- Andy - Arlington TX

I generally don't do through tenons so I round over the corners of the tenon. Unless I was doing a LOT of through tenons, I'd probably make the mortises by hand.

Mike

[Jim Dwight]

On my first Covid-19 project I used the domino for the carcase joints and to make the drawers of a 9 drawer dresser. Both are through joints. The dominos in the carcase hold the dividers for the drawers to the sides and show on the outside. The tenons are loose and home made. They have rounded edges. I just cut scraps to rough thickness and finished width on the table saw and use my planner to sneak up on finished thickness. Then the edges are rounded on the router table and cut to length on the table saw on a little sled made for this. The time involved is almost all setup so I try to make extra sticks for next time. The dresser used 5mm and 6mm tenons. A 1/8 round over bit works well. 12mm is almost 1/2 an inch so a 1/4 round over works great.

The pictures show a typical drawer joint and one side of the dresser upside down. The round shapes are plugs over screws, the dominos are the oblong shapes. The dresser is a bit of an experiment. I did not worry about wood movement. I may regret that but so far it is fine.

The domino mortises are very clean and precise in size. Very suitable for through tenons as long as the rounded edges do not bug you. The bits also did not break out on the second side even with no backer.

I've also used my XL to make 14mm wide mortises that were about 6 inches long in a crib. The tenons were traditional, I just rounded the edges with a rasp. When it doesn't show the round over isn't critical to make look nice. In my cherry bed, I used a bunch of 12mm thick by about 3 inches wide loose tenons I made of cherry scraps. I prefer the loose tenons because it avoids the need for cheek cuts which I find to be a little iffy. I often have to fine tune with a shoulder plane. The loose tenon avoids the extra work.

Angled mortises are not usually an issue for a domino. The fence adjusts easily to other angles than 90 degrees. I've only done miters so far and made a little jig for that. I don't know what you need to make but I am confident a domino can do it but you might have to dream up a jig.

You appear to have space if you are thinking floor standing but I do not. I like the fact the domino takes up so little shop space. But the main advantages are accurate mortises quickly and easily.

[Jared Sankovich]

Old Iron HCMs as stated are relatively inexpensive. The domino is nice (I have a xl in addition to my hcm) but doesn't replace the need for a mortiser.

[Jim Dwight]

Domino replaced my mortiser in my shop. I haven't put it on Craigs list but I will. I am space limited but I see no need for the hollow chisel mortiser. Maybe if you really need square corner mortises but you could chisel a domino mortise.

[mreza Salav]

I had a tilting spindle hollow chisel mortiser (General Int) that I specifically bought to do square holes for stair railing for our house I was doing and sold it after. Not something I would use regularly for mortises. I have used router jigs and in the past few years since I got Domino XL it will do 99% (or more!) of the tasks I'd need.
I considered buying a slot mortiser attachment for my J/P combo but don't see much value given Domino (yes, Domino Rocks!)

[Jared Sankovich]

Domino replaced my mortiser in my shop. I haven't put it on Craigs list but I will. I am space limited but I see no need for the hollow chisel mortiser. Maybe if you really need square corner mortises but you could chisel a domino mortise.

Sash is the first thing that comes to mind where a domino will not work. Really anywhere where the part is too small or delicate for a floating tenon, or where you need a square shaped mortise (not talking about the corners)

[Erik Loza]

I see them from time to time in local shops. Always some ancient cast iron beast but never actually seen any shop actively using one. Always sort of lumped them in there with things like overhead pin routers or the giant open-wheel bandsaws: From an age gone by.

Erik

[Brian Holcombe]

I see them from time to time in local shops. Always some ancient cast iron beast but never actually seen any shop actively using one. Always sort of lumped them in there with things like overhead pin routers or the giant open-wheel bandsaws: From an age gone by.

Erik

The age hasn't quite gone by since I use one nearly daily. Perhaps context should be provided, as usual.

If your factory is producing kitchens, then you won't be using a hollow chisel mortiser.

If you are making studio furniture, then you will find use for a hollow chisel mortiser.

They aren't commonly used because maintenance effort is required, you have to sharpen the chisel and make sure the machine stays in good shape.

English and Japanese mortisers are not necessarily gigantic behemoths that take up 50 sq ft.

[Mike Henderson]

I see them from time to time in local shops. Always some ancient cast iron beast but never actually seen any shop actively using one. Always sort of lumped them in there with things like overhead pin routers or the giant open-wheel bandsaws: From an age gone by.

Erik

Are you speaking of a hollow chisel mortiser, or a horizontal slot mortiser? Your mention of an ancient cast iron beast leads me to think horizontal slot mortiser.

I used a horizontal slot mortiser in school (a few years ago). It got quite a bit of use by students making furniture. It was the easiest and most accurate way to make a mortise.

But I agree that they are big and take a lot of space for something you won't use that often. Today, I make most of my mortises with a Domino.

Mike

[Erik Loza]

Mike, I'm talking about a free-standing vertical hollow-chisel machine. Wish I had taken photos of the last one I saw in a shop in Waco.

Erik

[Darcy Warner]

The age hasn't quite gone by since I use one nearly daily. Perhaps context should be provided, as usual.

If your factory is producing kitchens, then you won't be using a hollow chisel mortiser.

If you are making studio furniture, then you will find use for a hollow chisel mortiser.

They aren't commonly used because maintenance effort is required, you have to sharpen the chisel and make sure the machine stays in good shape.

English and Japanese mortisers are not necessarily gigantic behemoths that take up 50 sq ft.

Also, comparing domino's, floating tenons, etc. to actual M&T joinery is laughable at best.

Let me know how long that passage or entry door holds up with modern lazy joinery vs. actual M&T.

I find it basically impossible to be without a chain mortiser or HCM. Have no real use for a slot mortiser.

[Kevin Jenness]

"Let me know how long that passage or entry door holds up with modern lazy joinery vs. actual M&T."

Is 35 years long enough for you?

A well proportioned, fitted and glued spline tenon is quite sufficient for most purposes. In conjunction with cope and stick tooling it can be a good choice for doormaking. I have a hollow chisel mortiser for situations that call for square-ended through mortises or where the pieces are too small for inserted tenons like sash joinery. Otherwise I find myself using the stationary slot mortiser or Domino.

[Joe Calhoon]

Here’s a pair of doors I made 42 years ago with a slot mortiser and loose tenons. Joints are as tight today as when they came out of the clamps. This is a fairly unprotected exposure as well. The corner connection is important and properly done - dowels, dominos and loose tenons are fine for most applications. I like to do true M&T whenever I can but not practical in all applications if you are in the custom joinery business.
To me what’s laughable is shops using push pull tenoners and sash stickers for building custom doors and windows.

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[Darcy Warner]

Sure thing Joe. Laughable.
I can make more tenons on a tenoner then a shaper any day.

Btw, check will be in the mail.

[mreza Salav]

Also, comparing domino's, floating tenons, etc. to actual M&T joinery is laughable at best.

Let me know how long that passage or entry door holds up with modern lazy joinery vs. actual M&T.

I find it basically impossible to be without a chain mortiser or HCM. Have no real use for a slot mortiser.


In most documented tests a floating tenon of proportionally proper size isn't far from a traditional M&T. If you think of it, a M&T has two non-symmetric ends and a floating tenon has two symmetric ends. If a floating tenon is going to fail for the same reason M&T has a 50% chance of fail too. Again, in most (not all) situations they are equally good.

[Don Peters]

I have one of John TenEyck's horizontal router mortisers, and it's the cat's meow at a very reasonable price. It does everything I need including angles. He doesn't advertise, but you can PM him from this site.

[Don Peters]

I have one of John TenEyck's horizontal router mortisers, and it's the cat's meow at a very reasonable price. It does everything I need including angled mortises. He doesn't advertise, but you can PM him from this site.

dp

[Jim Dwight]

Do you mean square like a square dowel? If so I agree a domino won't do it. i would just use a dowel. I'm working from memory but I think the width of one plunge of a domino is 13mm plus the diameter of the bit. So for a 4mm bit, the width would be 17mm or under 3/4 inch. If you need a smaller mortise you would need another tool. I am confident I will not have that need often enough to keep another tool in my space challenged shop.

[Brian Holcombe]

Nice work, Joe. Great looking doors.

I have found little need for a domino, personally. I have a router, milling machine, hollow chisel mortiser and a swing chisel mortiser. If I added another, given some change in the current amount of space available I would consider adding a Balestrini style mortiser for round ended tenons rather than something like a domino.

[Jared Sankovich]

Do you mean square like a square dowel? If so I agree a domino won't do it. i would just use a dowel. I'm working from memory but I think the width of one plunge of a domino is 13mm plus the diameter of the bit. So for a 4mm bit, the width would be 17mm or under 3/4 inch. If you need a smaller mortise you would need another tool. I am confident I will not have that need often enough to keep another tool in my space challenged shop.


Yes square mortises for square tenons, or any variant of tenon shape not readily produced by the domino. (Less then the minimum width)

432987

432999

I'd take a horizontal or maka (the small one) over the domino.

[Andy D Jones]

Nice work, Joe. Great looking doors.

I have found little need for a domino, personally. I have a router, milling machine, hollow chisel mortiser and a swing chisel mortiser. If I added another, given some change in the current amount of space available I would consider adding a Balestrini style mortiser for round ended tenons rather than something like a domino.

Okay, I'll be the dummy; what is a "swing chisel mortiser"?

-- Andy - Arlington TX

[Jared Sankovich]

Okay, I'll be the dummy; what is a "swing chisel mortiser"?

-- Andy - Arlington TX


https://youtu.be/D_QNcFfWLwE

[Jim Becker]

I have found little need for a domino, personally. I have a router, milling machine, hollow chisel mortiser and a swing chisel mortiser. If I added another, given some change in the current amount of space available I would consider adding a Balestrini style mortiser for round ended tenons rather than something like a domino.

Where you might find it convenient is for things like large surface assembly and glue up...the portable tool is a lot easier to work with on long and heavy stock that is typical of those kinds of things. The knock-down features are also nice if required for a project. You (you personally) would get less benefit from Domino/Domino XL for other joinery because of the two amazing mortisers you already have reconditioned and put into use in your operation. If you haven't played with one, we can do that next time you visit if you want to.

[Andy D Jones]

Nevermind, found the following video that shows how it works (about halfway through)

https://www.youtube.com/watch?v=E2Kk8wD-D7A

Kinda sorta like a domino mortiser, but with a funky chisel, not a rotating bit. It creates rectangular mortises, but with the bottom slightly radiused. Very interesting!

Oops, thanks for the informative replies.

Does anyone make a "portable" swing chisel mortiser that clamps onto the work?


-- Andy - Arlington TX

[Kevin Jenness]

Andy, that's an interesting observation. I would have said the only thing they have in common is the oscillation, but I guess there's no reason you couldn't mortise the end of a rail for a spline tenon. Each size of mortise (width x thickness) requires a separate and I would guess not inexpensive tool. I'm not aware of a portable unit.

A round end tenoner is best paired with a round end oscillating slot mortiser, so Brian may wind up with 3 mortisers shoehorned into his shop.

[Joe Calhoon]

Nice work, Joe. Great looking doors.

I have found little need for a domino, personally. I have a router, milling machine, hollow chisel mortiser and a swing chisel mortiser. If I added another, given some change in the current amount of space available I would consider adding a Balestrini style mortiser for round ended tenons rather than something like a domino.
Thanks Brian,
I have a Domino but only use it for odd joinery. Mostly connecting curve door and window parts that are difficult or too large to get to the mortiser. It would be tedious doing a lot of mortising with one. However they are a ideal mortiser for the hobby - home type shop with limited machinery.
the DM is becoming my favorite mortiser now with my reduced work load.

[Joe Calhoon]

Nevermind, found the following video that shows how it works (about halfway through)

https://www.youtube.com/watch?v=E2Kk8wD-D7A

Kinda sorta like a domino mortiser, but with a funky chisel, not a rotating bit. It creates rectangular mortises, but with the bottom slightly radiused. Very interesting!

Oops, thanks for the informative replies.

Does anyone make a "portable" swing chisel mortiser that clamps onto the work?


-- Andy - Arlington TX

Andy, don’t think it would be possible to have a portable swing chisel Maka type mortiser. There is a lot of pressure on the chisel requiring high clamping pressure of the workpiece. I had a piece come out of the Maka once and it went airborne with tremendous velocity. They make portable chain mortisers and I believe portable HC mortisers.

[Tom Dixon]

I purchased the Grizzly G0840 (https://www.grizzly.com/products/Grizzly-Mortising-Machine-with-XY-Table-and-Stand/G0840) about a year ago and I'm pleased with it's performance so far.
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