Marking out Moritises

Right, you've got your mortise chisel of the correct width (~1/3 width of the board) and armed with marking gauge, saddle square, etc.
How do you ensure that the marking gauge is set just right so that running down both sides marks out exactly the width of the chisel?
Is it just guesswork, euclidean geometry tricks, measuring or just some other method? What's the way that gets the girls.... ?
many thanks
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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Is your marking gage a mortise gage (makes two marks)? If so, I set the mortise gage to width and check it on a piece of scrap wood. When I get the width I want, I mark the work piece. If your marking gage is a single pin, you will have to play with the settings until you get it correct. I try to get the width marked so that the chisel just kisses the mark on both sides. When I'm chopping the mortises, I align the chisel on only one of the lines. I find that helps with my consistency.

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"RichardS" wrote in message

I use a mortise gauge and a 6" rule. The mortise gauge scribes two parallel lines, referenced to one edge of your work piece. It is a simple matter to hold it up to the rule and set both the mortise width and the distance from the reference edge.
If you'll be doing a lot of mortises, a mortise gauge is a real time saver.
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RichardS wrote:

Several different marking gauges for moritse and tenon
http://home.comcast.net/~charliebcz/MTPrimer9.html
If you wanta great, easy, though not inexpensive, layout/ marking tool check out the Tite-Mark. If the price tag is an issue - consider the price of the wood you'll need to mortise and tenon in your current or near future project
http://home.comcast.net/~charliebcz/MTprimer10b.html
charlie b
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Thanks for the responses, folks.
It's just a standard marking gauge, not a mortise gauge - I can see that a mortise gauge would save time 'cos once it's set to the width of the chisel the only adjustment is for the offset from the edge of the stock.
Reading Frid pt 1 last night reveals that he recommends a marker cut with the chisel to the edge of the stock to set the width, and ensure dead-centre mortise. However, this would only work if the chisel was exactly 1/3 the width of the stock, which given stock preparation discrepancies and standard chisel sizes is not a safe bet.
I'm still stuck with the problem of how to make sure the mortise ends up exactly in the centre of the stock.
I know that measuring is one possiblity, but tricks relying on geometry are usually more accurate and less prone to "user error"
thanks
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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I *think* the way I've Seen roy Underhill do that is to set the gauge to the width of the chisel, setting it with the chisel itself--no rulers are used.
Then he uses the same gauge to mark both the mortise AND then tenon. That way any offset in centering is the same for both, provided both are measured from the same side of the piece. If you cut both the mortise and the tenon right to the center of the line you should get a perfect fit.
If it is a haunched tenon then another gauge, or the pin on the other side of the mortising guage is used to set the depth of the haunch on both.
Let me know if it works. (;-)
--

FF

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snipped-for-privacy@spamcop.net (Fred the Red Shirt) wrote in message

Apologies for following up to my own article but that should read 'If it is NOT a haunched tenon...set the depth of the soulder on the narrow side of the tenon.'
Also, you can cut your tenons first, then set the mortising guage to the width of the tenon.
--

FF

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I usually find myself cutting mitred haunches when haunches are required, especially for my current project (2nd out of 8 wardrobe doors just approaching completion).
My enquiry isn't so much how to set the width of a mortise gauge to the width of the chisel (as someone else pointed out, use the chisel width as the guide!!!), but rather given a rail and stile of the same thickness, how to mark the mortise such that it is always properly centred in the stile.

Hmmm, all guides I have read say cut mortise first, the width of this being determined by the available width of the closest suitable mortise chisel. This works for me.
Tenon cutting, unless done purely by hand, is pretty much a symmetrical procedure - set fence on bandsaw/tablesaw (or in my case set depth stop of router - sorry, know that hogging off tenon waste with a router is unconventional, but it's quick and (given my quickly-constructed jig) accurate), cut one side, flip stock over, cut other side. As long as fence set correctly the tenon width will be correct for the mortise.
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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I've tried various methods, and the one I use now is probably different than most. I take a single wheel marking gage and set out the distance from the front/face side that I want. (I always reference my mortises from the front.) I scribe the front of each mortise I will be cutting. Then I lay the chisel down next to one of the gage marks and take another gage and extend it (again referencing the front side of the piece) so it reaches just past the far side of the chisel.
To make sure it's the width I want it, I take a piece of scrap and mark both sides of the mortise and check it against the marks on the scrap. I actually make my mortises a little bit (probably 1/64th or so) wider than the chisel. I found that if I aimed for having them exactly the same width, it was too easy to overrun the scribe line on one side or another. This way I (hope to) keep my scribe marks intact and can clean them up if need be with a wide chisel set in the mark.

It's all in how you use your tools.
Chuck Vance
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On 25 Feb 2004 05:13:00 -0800, snipped-for-privacy@swt.edu (Conan the Librarian) brought forth from the murky depths:

Paying attention, having good lighting, and wearing clean eyeglasses all don't hurt, either.
---------------------------------------------------------- --== EAT RIGHT...KEEP FIT...DIE ANYWAY ==-- http://www.diversify.com/stees.html - Schnazzy Tees online ----------------------------------------------------------
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(Conan the Librarian)

That helps you get girls?
Chuck Vance
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On 26 Feb 2004 04:57:51 -0800, snipped-for-privacy@swt.edu (Conan the Librarian) brought forth from the murky depths:

Just Molly Mortice.
P.S: Time to clean my computer glasses. I hadn't even noticed the sentence in question.
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One way is to use a motising guage, set to the width of the chisel.
--

FF

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Graham Blackburn demonstrated his technique at a recent (Oct, Costa Mesa, CA) ww show. He's a tenon first guy. He determines the tenon width based on the chisel that most closely approximates the calculated width (I forget if he's a half or 1/3 guy). Once he makes the tenon, he uses the tenon to mark the mortice. He marks both ends of the mortice, but only one line for the width, offset from the face of the stock. He figures if he works off this one line, the other side will take care of itself (the chisel tends to remain a constant width).
Cheers, Eric
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Right, I've figured out something that works fairly well for me.
I'm just using a normal marking gauge for this at the moment - a mortise gauge is on the cards next time I'm at the toolshop. I was wondering how a mortise gauge would help me mark a dead-centred mortise even though setting the width of the mark is trivial (set to width of chisel), but the answer is obvious - trial and error adjustment until marks taken from both sides coincide.
I set the gauge to mark a mortise that is obviously a few mm narrower than the chisel - light marks made from both faces.
Then, light mark with the chisel from one mark, crossing the other side's mark.
Reset the marking gauge so that it bisects the "overhang" on the chisel mark - this is easy to do with relative accuracy by eye.
Then mark both sides and it should be pretty much the width of the chisel, dead centred on the stock (if you have been accurate in the bisection reset).
Conan, I hear what you say about only ever marking from the reference face - this would seem to me to be the only "correct" strategy for accurate marking. However, unless you are cutting the tenons by hand, the tenon cutting process is generally symetrical - ie you'd not want to have to continually reset the fence on (eg) the bandsaw to cut each side of your tenon to bang on the marks (which might not be centred on the stock). You'd ideally just want to flip over your stock and cut the other side of the tenon, which would result in a symetrical tenon, which might not marry exactly with your marked mortise.
Anyway, thanks for the suggestions, sorry if it sounded like a trivial and obvious question to ask.
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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Precisely. I saw them by hand. :-)
Sorry I didn't realize that your original question related to exactly centering things. It's so rare that I do a m&t that is exactly centered that it didn't dawn on me. :-) Many times I intentionally offset them towards the face (i.e., when m&t's meet in a stile), and other times I just don't worry. As long as they are flush when they're supposed to be, I figure it's no big deal.
Chuck Vance
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: I'm just using a normal marking gauge for this at the moment - a mortise : gauge is on the cards next time I'm at the toolshop.
Before spending his lolly, Richard might like to look at my web site - Marking Out Notes - Make Your Own Gauge.
Jeff G
-- Jeff Gorman, West Yorkshire, UK Email address is username@ISP username is amgron ISP is clara.co.uk Website www.amgron.clara.net
I was wondering how a : mortise gauge would help me mark a dead-centred mortise even though setting : the width of the mark is trivial (set to width of chisel), but the answer is : obvious - trial and error adjustment until marks taken from both sides : coincide. : : I set the gauge to mark a mortise that is obviously a few mm narrower than : the chisel - light marks made from both faces. : : Then, light mark with the chisel from one mark, crossing the other side's : mark. : : Reset the marking gauge so that it bisects the "overhang" on the chisel : mark - this is easy to do with relative accuracy by eye. : : Then mark both sides and it should be pretty much the width of the chisel, : dead centred on the stock (if you have been accurate in the bisection : reset). : : Conan, I hear what you say about only ever marking from the reference face - : this would seem to me to be the only "correct" strategy for accurate : marking. However, unless you are cutting the tenons by hand, the tenon : cutting process is generally symetrical - ie you'd not want to have to : continually reset the fence on (eg) the bandsaw to cut each side of your : tenon to bang on the marks (which might not be centred on the stock). You'd : ideally just want to flip over your stock and cut the other side of the : tenon, which would result in a symetrical tenon, which might not marry : exactly with your marked mortise. : : : Anyway, thanks for the suggestions, sorry if it sounded like a trivial and : obvious question to ask. : : -- : Richard Sampson : : email me at : richard at olifant d-ot co do-t uk : :
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wrote

Jeff,
your website is pretty much my instruction manual on mortise-cutting. Technique coming along nicely, many thanks for the detailed instructions!
Never again will I feel the urge to pre-drill a mortise, and I'm not remotely bothered about acquiring a mortising machine.
Time constraints have unfortunately meant that I had to resort to power tools to cut the tenons, but this works fairly well for me and I'll return to hand cutting them when I get my hands on a decent saw (considering one of the reasonable priced axminster japanese rip saws at the moment).
many thanks Richard
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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