Chiseling a Mortice

[ballen]

Has anyone ever posted a tutorial on what to do after you use the boring machine?  I'm sure my chiseling technique could use some refining.  I've already nipped my finger once chiseling out the thru tenon:-(

I also need a reference on sharpening a chisel. Like an idiot, I was working on my table saw (using a short practice timber) when I first chiseled thru the thru tenon...yup, I just caught the steel table top and now have a slight flat section on my nice new-to-me framing chisel.

Thanks in advance.

[Dave Shepard]

Once you have bored the mortise (mortice), clean up the sides the best you can, getting fairly close to the corners. Some use a corner chisel, but a chisel that is right size for the width works better, in my opinion. Just put the chisel on the end of the mortise and drive it home. Now pull it towards the cleaned out mortise, and it should break the corners out nice and clean. If you didn't get the width of the mortise cleaned out wide enough, you will get the chisel stuck, not good. Once you get a feel for it, and the proper order, it becomes very fast.

Best way I know of to keep from getting cut is to keep both hands on the tool at all times, unless you are striking with a mallet. I would say most chisel/slick injuries come from resting one hand on the timber either for balance, or to support an un-clamped timber. Not good.

I'm sure there is some sharpening advice around here somewhere. I use a combination of diamond (DMT brand) and waterstones. I also use a Veritas MKII jig to make it easier to maintain the angle. If it's really bad, you need to start with a very coarse stone and get the nick out, then progress up to the finest stone you have. It cannot be too sharp. As an example, I go up to 8000 grit on the waterstone, and then strop with the green compound. Stropping when you feel the edge starting to dull lets you go longer before you have to put the tool in the jig and hone off some meat on the tool.

[Jim_Rogers]

Bill:
Check out Tim Beal's videos on YouTube if you want to see some fancy mortise clean-ups.... very good job in both videos...


oops forgot the link:
http://www.youtube.com/user/MoonHillFarm

[Jim_Rogers]

Also, there is a thread around here somewhere about establishing some "General frame rules" used when you are designing a frame.

They are such things as each joint is made 1/2" under the size of the timber.
All layout is done from the west end of the building except the east most bent.

And also, layout is 2" off the reference face and then 2" thick..... for smaller timbers it is 1 1/2" off reference face and then 1 1/2" thick.....
But it really doesn't matter.

What is important is that you use these rules as a process order as well as a layout order.

What I mean by that is you need to make sure the mortise is 1 1/2" or 2" off the reference side first, then make it two inches wide.

That way you're not making it too wide if you work on the wrong side first. Once you have the width of the mortise done from end to end; you can then work on the ends.
And if it is the right/correct width the 2" or 1 1/2" chisel you're using won't get jambed in if the mortise is two narrow at the ends.

Check the width of the mortise with a framing square if making them 2" and 1 1/2", as I know you're making your mortises narrower for your out building project, use a steel ruler like the one from your combo square to check your 1" mortise.

Hope that helps,

Good luck.

Jim Rogers

[Jim_Rogers]

For my own education I just checked the spelling and mortice is a variant of the word mortise according to Merriam Webster's online dictionary.

My online spell checker underlines mortice as an incorrect spelled word, so I just wanted to know why....

Basically it can be used but to be correct the spelling is "mortise"......

[Dave Shepard]

My spell check likes mortice, and mortise. It usually prefers UK spellings, I think I have a UK version of Linux. :D

[Brad_bb]

Boy, where to start here...
First, Chiseling on top of your table saw??  Not good for either tool.  If you're going to do this, you need timberframe sawhorses or Cribbing ponies.  There is a past post with plans for each, or ask and you shall receive.  I like the cribbing ponies.  They are smaller and can be stacked, you just need to add cribbing timbers to get your workpieces to the proper work height.  Here are my ponies:



   Do not attempt to work on a short or small timber without clamping it.  That is how you end up in awkward positions and end up putting your hand where you should not.  Larger timbers that are heavy enough to resist movement do not need to be clamped, but brace timbers and other small stuff need to be.

   There are quite a number of ways to sharpen- machine like Tormek or Worksharp.  Costly but have their advantages especially if you have to sharpen a lot.  Sandpaper and glass method, cheap and effective- my preferred method.  Then there are natural stones, Synthetic stones, and diamond sharpeners.  If I missed a method my apologies.  You don't need a special angle guide for sandpaper or stones.  Your sharpening method will be what works best for you.  Here's some additional info from a past post:

https://forestryforum.com/board/index.php/topic,41576.0.html

Here's my sharpening station:



   Yes watch moonhills vids as Jim suggested.  Proper technique with the chisel, a sharp chisel, is critical for good performance and preventing frustration.  Do you understand how to pare and work with the grain?  Scoring your lines can also help you have a place to rest your chisel tip exactly on the line.  Doing the end grain is physically harder.  Make sure you are chopping vertical and not letting the chisel angle.
   I too originally spelled it "mortice".  But being on these forums, everyone spells it "mortise", so I do now as well.

[Dave Shepard]

The first video shows good use of the corner chisel. Whenever the holes don't overlap just a little, it can be tough to get that wood out with a chisel. Going down the middle with the corner chisel gives the wood somewhere to go when paring with the slick or chisel. The second video shows how handy an axe can be for roughing out joinery. Great videos! 8) Thanks.

[Piston]

In regards to learning about sharpening techniques, I would recommend reading "The Perfect Edge" by Ron Hock.  I just started reading it about 3 nights ago and have learned so many things that I had been doing wrong.  I am by no means an expert at sharpening (actually not even really a novice yet :D) but it's amazing how much I've learned about technique, now I just need to practice. 
http://www.amazon.com/Perfect-Edge-Sharpening-Woodworkers-Woodworking/dp/1558708588/ref=pd_sim_b_2

[routestep]

I bought some Hock irons for some of my hand planes. They are very nice pieces of steel, hard and thick.

When I chisel out a mortise I have a combination square handy to measure as I go. I have the combination blade down in the mortise hole and check that I am going straight down as I chisel the sides and ends. I have to check a lot and I'll still might under cut the width. I also use the framing square to check the width of the finished mortise. If the blade (or tongue for 1.5") doesn't fit smoothly all along the length of the mortise then I chisel a little more.

On timbers that are not square I have to use the combination square in combination with the framing square. The framing square is pressed up against a reference face and the combination square handle is on the framing square. Then the combination's blade can check the mortise sides and ends.

Keep your chisels sharp.

[ballen]

Thanks all,
Since posting, I have built a sharpening station (sandpaper on glass) since I had these items lying around.  I have achieved a mirror finish on my old chisel in no time with 5 grades of paper (280 to 2000 grit).
I still hesitate to use my chisel as a "lever" to clear out the wood on the bottom of the mortice to get it flat but I now realize it doesn't need to be as perfect as the sides because you want a little gap so the tennon doesn't bottom out anyway.  None the less, is there a better way to get the bottom flat between the boring holes?
After fixing my chisel, I now have a grand total of 2 mortices under my belt.  Lot's more to do in the next couple weeks. 
Thanks again.