Replies

1. 
   SteveSchoene | Oct 06, 2008 05:46pm | #1

   Hide glue takes dye better than PVA glue, but you can't really say that it takes just like the wood around it.  But, filling gaps with glue isn't the answer.  Inserting tapered slivers, cut so that the grain that is left matches that on the show surface is the way to go. 

   You don't say what the errors look lilke so it is hard to give good advise on how to improve the mortises.  Some things to consider: 

   Marking out is the first really important thing.  It is important the boards you are making the mortises into are four-square.  Then you must use a consistant reference surface to run your square and mortise gauge.  Remember you are marking out two mortises, one on the reveal side and the other on the inside.  With square lumber and using the same reference surface to mark each side with, the marking should place the openings directly opposite each other.  Pencils can't be precise enough, and give you no tactile mark to start your chisel, or cut to stop a splinter from running outside of the lines. 

   Mortises need to be worked from both sides.  If chopping them is better, then chop the reveal side--it only needs to be shallow, say 1/2" deep.  Then the mortise from the other side can be deeper to meet the shallow mortise on the show side.  If the meeting isn't precise, you can make adjustments entirely inside the mortice where they won't show. 

        

    

2. 
   Rich14 | Oct 06, 2008 06:49pm | #2

   Bonka,

   To add to Steve's instructions -

   You can do this. PERFECTLY formed mortises are NOT impossible to achieve! Read this through a few times.

   As he said, your work MUST be square all around. Is it?

   After you establish the (rough) location of the mortise with pencil lines . . .

   You MUST reference the long sides of the mortise from the SAME reference face of the wood. First set the mortise gauge and reference one side of the mortise on the reveal side. Don't change the setting. Using the same reference face, establish the matching mortise face on the hidden side.

   Use the tenon to establish the mortise width from that first mark, marking the width with a knife, then change the gauge setting to that mark, marking the WIDTH of the mortise using the SAME reference face as before. Mark the reveal side, then the hidden side all from that same reference face.

   Then establish the ends of the mortise. With a marking knife, strike a line establishing one end on the reveal side. With a tri-square and marking knife, carefully and exactly take that line around onto the adjacent face, then to the hidden face, establishing that same end of the mortise.

   Mark the other end of the mortise in the same way using a marking knife and the tenon to get the measure. Hold the knife in the first line, bring the tenon against it, hold the tenon in place, move the knife and mark the tenon length. Mark all around the piece with the knife and tri-square.

   You will then have the mortise marked out with the entry and exit PRECISELY opposite each other and with knife lines to hold a chisel in place.

   DON'T START CHOPPING with the chisel in those lines. The wood tissue that needs to be removed within the mortise opening will drive the chisel backward from the intended mortise walls, destroying all accuracy and creating an over-sized, out-of-square mortise. Instead, waste as much of the mortise as possible with a drill bit or router bit smaller than the mortise opening, coming as close as possible, but not touching the knife marks.

   Use a drill press or whatever you need to help you to keep a hand drill square to the work. Use a drilling jig. Or have a helper sight one axis of the drill bit for square, as you keep the other square to the work.

   With the mortise drilled out, pare/chop with a VERY sharp chisel, using the knife lines to hold the chisel edge to establish the location of the mortise walls. With the chisel edge in a knife line, bring a square block up against the face of the chisel (the face opposite the bevel) and clamp it to the work to keep the chisel square into the mortise.

   You can pare/chop halfway through from each side. Or you can go about halfway through from one side, then use a straight router trim bit (the kind with the guide bearing at the end of the bit) to reach through from the opposite (rough) side. The guide bearing rides on the finished walls and the bit exactly trims the rest of the mortise. You will then need to square up the corners.

   It all sounds MUCH harder than it is. It's faster to do than to explain. Careful, thoughtful layout with SQUARE stock, a marking knife for accuracy and knife lines to guide your chisel are the secret. Once you get the first one to work and the rest just fall in line, you will not understand how you could have struggled so much!

   Rich

   
   

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   Edited 10/6/2008 12:15 pm ET by Rich14

1. 
   Bonka | Oct 07, 2008 12:13am | #4

   I have no trouble making the mortises. I use a router which of course leaves round corners. I have marked the areas to be pared with a sharp line.  My problem is paring away the corners to square. I may be taking too large of a bite with the chisel. The chisels are sharp. I can get a shaving from pine end grain.  I must be trying to take off too much. I work from both sides half way. If I could only recall how I did the one that came out good. At the moment I am going to give it all a rest. I have had enough for awhile.  The maple I am using is harder than Woodpecker lips. The chisels do not feel right in my hand and I feel clumsy using them.  I guess I will plod on at a later date but feel I must get away from it for a time.

   Thanks to everyone for advise.

1. 
   dkellernc | Oct 07, 2008 01:08am | #5

   Bonka - I read your earlier thread about chopping these through mortises.  You've gotten good advice, but most hand-tool perfection in woodworking comes with #1 - the correct techniques, and #2 practice.  You can't achieve good results if you're not practicing the correct techniques, and with some aspects of hand tool use it may take many more than 30 attempts to do it without thinking about it.

   However -

   It occurs to me that what you're attempting to make is "Arts and Crafts" furniture, of which through tenons are a halmark feature.  Be aware that almost none of the authentic Arts & Crafts antiques made in the early part of the 20th century was made by hand, at least with hand tools unassisted with power tools.  The point here is that it may not be realistic to expect to create perfect through-tenons with a mortising chisel.  I'm not saying that it can't be done, just that's not the way it was done on the original pieces. 

2. 
   SteveSchoene | Oct 07, 2008 04:16am | #6

   This should be solvable. 

   First, make sure that the knife cut that marks your lines is accurately placed and deep enough to rest a chisel in.  But, DO NOT start to chisel at that line--not until no more than 1/16" of waste remains..  The wedge shape of the chisel would drive the flat edge of the chisel past the line.  On the ends of the mortise, start with the chisel a shy 32nd inside the line, and with it held vertically, flat side toward the line, tap it until the blade moves just to the line. 

   Then, move away from the end and pare the waste away from the lines, leaving about 1/16th of an inch of waste all around, perhaps a little less on the sides.  For the sides use a wide chisel say an inch or even more so you can par using the machine cut sides to help keep the chisel on line.  Then finally, when you have cleaned the sides, and have only a 1/16" of waste on the ends, can you use your 3/8" chisel, set firmly in your deepened cut line and pare away the remaining waste. 

1. 
   Bonka | Oct 07, 2008 04:33am | #7

   That helps me a great deal. I am going to give it a try when I get back at it. Right now a 5 piece bird house looks good. I may chop one out this weekend, but no mortises.

    

3. 
   joinerswork | Oct 06, 2008 08:45pm | #3

   Bonka,

   There are two reasons that through tenons are usually wedged:

   1) The reason you tell the customer: the use of wedges splays the ends of the tenons somewhat, ensuring that they cannot be withdrawn, even of the glue fails.

   2) The real reason: wedged tenons will nearly always fill the mortise perfectly on the show side. 

   Just be careful not to wedge so tightly that you split the mortised member.

   Dovetails are sometimes wedged this way too, "for strength" ;-))

   Ray