Mortise in thin and narrow stock - which is the easiest and fastest way?

[Niels J. Larsen]

I needed to create a mortise (15mm or ca. 3/5") wide in some thin (8mm or ca. 1/3") and narrow (20mm or ca. 4/5") stock.

After thinking a bit about it and trying to rout it freehand, I settled on using a 15mm forstner bit and cleaning it up with a chisel.

I can't explain why, but I just like the very clean look that is easily achieved with a router. It can of course be obtained by the method above, but it takes me longer.

Is there an easy and fast (and safe!) way to do this with either a freehand router (Bosch GMF 1400, Festool OF1010 or Festool OF1400) or a router table?

By the way - the stock is approx. 38cm (or ca. 15") long.

Thanks,
Niels

[Bill Huber]

I am not sure you can get them over there but a Mortise Pal would work.

http://www.mortisepal.com/

[Joe Chritz]

I make a "box" that my plunge router just rides in front and back with no sideways play. Route a slot through the bottom and attach a stop to limit front to back movement. That slips over what ever I am putting the mortise in and gets clamped on while I route the slot.

With very thin stock you would likely have to double face tape it down to something else first but I don't see why it wouldn't work.

It is one of my regular router jigs and gets rebuilt often. Someday I want to build a better permanent version.

Joe

[Niels J. Larsen]

I am not sure you can get them over there but a Mortise Pal would work.

http://www.mortisepal.com/

Thanks for the suggestion.

I was thinking along those lines but according to their specifications it won't work for this exact task:

Maximum Mortise Width = 1/2"
Maximum Mortise Length = 3-1/2"
Maximum Stock Thickness = 3"
Minimum Stock Thickness = 3/4"
Minimum Edge to Mortise Center = 3/8"

/Niels

[Frank Drew]

Niels,

Find someone with a horizontal slot mortiser (basically an easier way to do the same job as the router) and the appropriate size bit. Zip, zip, zip, zip... and you're done.

[Niels J. Larsen]

I make a "box" that my plunge router just rides in front and back with no sideways play. Route a slot through the bottom and attach a stop to limit front to back movement. That slips over what ever I am putting the mortise in and gets clamped on while I route the slot.

With very thin stock you would likely have to double face tape it down to something else first but I don't see why it wouldn't work.

It is one of my regular router jigs and gets rebuilt often. Someday I want to build a better permanent version.

Joe

Thanks Joe, but after having read your post three times I'm still unsure exactly what your jig looks like :o

Do you by any chance have a picture?

Again - I'm not sure I understand it correctly - but wouldn't your jig require me to use a router bit matching the width of the mortise?

/Niels

[Niels J. Larsen]

Niels,

Find someone with a horizontal slot mortiser (basically an easier way to do the same job as the router) and the appropriate size bit. Zip, zip, zip, zip... and you're done.

Thanks Frank.

The problem is I don't know anyone apart from a pro, that would have a horizontal slot mortiser.

I could buy one myself, but what I've seen so far, I think it'd run into the same problems as I would if I was using the "Mortising Pal" - namely that the stock is too small to fix in a safe manner.

/Niels

[Michael MacDonald]

Thanks Joe, but after having read your post three times I'm still unsure exactly what your jig looks like :o

Do you by any chance have a picture?

Again - I'm not sure I understand it correctly - but wouldn't your jig require me to use a router bit matching the width of the mortise?

/Niels

I have done this before with some success... Think of the box as a picture frame... The router plays freely within the frame and can move side to side or up and down... if the stock and the frame are fixed tightly, no matter where the router goes it will stay within the frame...

[Dave Gaul]

How about something like this?

http://www.sawmillcreek.org/showthread.php?t=142768

I just finished it this past weekend... easily customized to whatever size you need...

[Niels J. Larsen]

How about something like this?

http://www.sawmillcreek.org/showthread.php?t=142768

I just finished it this past weekend... easily customized to whatever size you need...

Great suggestion!

Thanks a lot!

/Niels

[Frank Drew]

Niels,

Before I got my slot mortiser, I used this plunge router jig for years and it was very simple to construct and use and it did very accurate work.

http://www.highlandwoodworking.com/tagefridsmortisingjig.aspx

As for fixing small work when using a slot mortiser, I never found that a problem, and I sometimes cut mortises in the end grain of small pieces; lengthened screw holes in hinges and other work in small metal pieces; etc.. I removed the single point fixing device that came with my machine and make a new bracket to hold two De-Sta-Co plunge clamps, mounted vertically.

http://www.destaco.com/img/prod/603-r.jpg

[Niels J. Larsen]

Niels,

Before I got my slot mortiser, I used this plunge router jig for years and it was very simple to construct and use and it did very accurate work.

http://www.highlandwoodworking.com/tagefridsmortisingjig.aspx

As for fixing small work when using a slot mortiser, I never found that a problem, and I sometimes cut mortises in the end grain of small pieces; lengthened screw holes in hinges and other work in small metal pieces; etc.. I removed the single point fixing device that came with my machine and make a new bracket to hold two De-Sta-Co plunge clamps, mounted vertically.

http://www.destaco.com/img/prod/603-r.jpg

Superb!

That's just what I was looking for!

Thanks!

/Niels

[Joe Chritz]

Clear as mud?

It isn't as adjustable as some of the others but it is very easy to make and re-make to fit projects. I have found that as long as I have more than two or three mortises to make that use the same stops it is well worth it.

Joe

[glenn bradley]

Thanks for the suggestion.

I was thinking along those lines but according to their specifications it won't work for this exact task:

Maximum Mortise Width = 1/2"
Maximum Mortise Length = 3-1/2"
Maximum Stock Thickness = 3"
Minimum Stock Thickness = 3/4"
Minimum Edge to Mortise Center = 3/8"

/Niels

I have used 3/8" stock with my Mortise Pal and use 1/2" frequently. I use spacer blocks to alter the minimums. Be that as it may I think a quick shop made jig would be faster than waiting for the overseas shipping (cheaper too).

If you have template collars for your router, use your Forstners to drill a couple holes and connect them with a jigsaw or a fret saw to make your mortise template. Screw on a "fence" and away you go.

These may help:

http://www.highlandwoodworking.com/tagefridsmortisingjig.aspx

http://www.woodstore.net/semojigpl.html

I like the second one myself.