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Preparing a hollow mortise chisel

February 4, 2010 By

One question from a reader prompts me to illustrate the process I use to prepare hollow mortise chisels before I even approach the benchtop mortiser.The process is called “tuning a hollow chisel”; it prepares the chisel for efficient cutting of the mortise, and eases penetration into the wood while minimizing burn marks. This results in smoother mortise walls, faster cutting, and better chip ejection while keeping the chisel cooler. So far I have not had to sharpen any of the drilling bits on any of the chisels.

In this photo you see the hollow chisel as received. The grinder marks are plainly visible:

Just like a bench chisel, the sides of the chisel should be lapped using either sandpaper or, as I show here, with sharpening stones. Following preliminary lapping on the 1,000-grit stone, I continue with the 6,000-grit or finer stone:

In this next photo you see how the steel begins to shine, and the tool marks have disappeared near the cutting edges – not quite ready for work, the chisel is getting close to being ready to cut:

Next I use a diamond-covered abrasive cone, to sharpen the inside surfaces of the tip of the chisel. The cone holder is part of a set available from various sources:

Careful inspection is a must, before using the chisel. Look carefully at the inside surfaces, to make sure the cone has left smooth, shiny surfaces:

Yup, that is the BenchCrafted tee shirt. And it is a shameless plug for the company that makes, along with 11 other winners, the Popular Woodworking magazine’s Best New Tools for 2009, the BenchCrafted Tail Vise. I was the lucky recipient of one tee shirt at the Valley Force conference:

To my friend Jameel Abraham, of BenchCrafted.com, and his brother Fr. John, congratulations for winning the award – it is well deserved!

Disclosure: I am a happy owner of one BenchCrafted tee shirt; I have no commercial or any other interests in BenchCrafted.com. And I love the vises they make.

— Al Navas

Filed Under: Blog, Education, Joinery, Mortise, Sharpening, Tenon, Tutorial Tagged With: , , , , , , ,

Using my new (old!) shooting board from Evenfall Studios

January 30, 2010 By

OK, I must admit it. I have had the shooting board from Evenfall Studios (Rob Hanson, Owner) in the shop since June of 2009. One thing led to another, and the board sat without use for several months. Even The Schwarz gave it a glowing review on his blog in early July, 2009; that review pushed me to (try to) use it – but I was unable to do so, as a result of a shoulder injury that has since healed for the most part.

With that mandatory preliminary out of the way, I found myself in a situation that needed correcting before I could assemble the standing desk. When I made the leg stretchers, I consciously left the tenons about 0.050″ too long, to be trimmed later; this made it much simpler to get the shoulder-to-shoulder length of the stretchers matched perfectly to the distance between the legs, front-to-back and near the top of the legs (in other words, square).

Later became today. You can see the gap between the stretcher (vertical) and the edge of the leg (horizontal):

The tenons are too long.

I could have used the table saw to trim the dual tenons, but I really, really wanted to try my hand with the shooting board. Of course, I don’t have a specialized shooting plane in the shop, like the one my friend Ron Brese makes (maybe Sandy will read this soon). But I had the old reliable Stanley #5 sharp and ready to go – a very good thing when you shoot the end grain (notice the end grain curlies?):

Shooting board in use.

Well…As expected, the Stanley #5 does not have the cheeks perfectly square to the sole, but it did a splendid job in trimming the tenons – all it took was a little fiddling with the iron angle using the lateral adjuster, and I was shooting square! Hint: Using a block plane, I put a little bevel on the back side of the unsupported tenons, to eliminate tearout.

After trimming off the 50 thousands of an inch or so, I was so excited I did not even realize the following photo was out of focus – the trimmed tenons, and a much tighter fit, before drawboring and tightening the stretcher to the leg:

Gap closed!

A neat feature of the Evenfall shooting board is its adjustable fence. I checked the fence for square before I started shooting, and after. The fence held very well:

Checking fence for square.

The Evenfall shooting board has accessories. I also bought the double-high fence (it comes with its own attachment hardware):

Accessories for the shooting board.

Notice the angled cut on the back side of the fences? The fences can be reversed, for angle cuts – pretty neat! And each is adjustable within a 5-degree range, very handy when shooting boards that will go into areas not quite square, such as moldings. And Made in the USA is a great thing, too, as part of the amazing revival of makers of hand tools. In case you are wondering about the features and specifications of the boards, I invite you read more on the Evenfall Studios page. And if you wish to buy one, you can place an order at the Evenfall online Store.

My Hint of the Day: Adjusting the hand plane iron for use on the shooting board (or just about any other use).

I know I have seen the following somewhere, but simply cannot put my finger where. Use a narrow strip of a softer wood; make sure only one corner contacts the sole and the blade. Now run the piece of wood across the blade from the toe toward the heel, near the corners of the iron, and at the center:

Checking iron depth of cut.

The result: You should have three very thin, almost identical shavings at each location, near the corners, and near the center:

Nice, thi8n shavings across the iron.

How do I like the shooting Evenfall board? My answer is that I just love it. I am certain it will become entrenched in my woodworking habits, as I integrate hand tools in the shop over time. I can’t wait to try my hand at miters! I will probably send one of my spare (old) hand planes to a shop for squaring, and to have a handle put on it. Or maybe I will try making one from some of the Osage Orange Sandy has near her lathe, since I already have the large iron from Brese Plane.

Disclosure: I am strictly a user of the Evenfall shooting board, and have no commercial or other ties with Evenfall Studios.

— Al Navas

Filed Under: Blog, Jigs, Joinery, Mortise, Shooting board, Tenon Tagged With: , , , , , ,

The Super FMT: Part 2 cont’d – more on the clamp plate

December 15, 2009 By

The weather is just about back to normal – we expect 4°F tonight, with (again!) winds around 15 mph. However, today was a good day to be in the shop; the furnace kept the shop at a toasty 65°F. I had a dovetail saw in hand, cutting dovetails for some drawers I must finish. And then it struck me: I had to resolve an issue I ran into with the Super FMT the last time I used it.

I like to check the joinery as I work, because it saves me headaches at dry-fit, and at glue-up time. So, checking each and every single joint is a hard-to-kick habit. After playing around with the Super FMT, moving clamps to and fro as I made mortises and then tenons, I found a misaligned joint:

mis-aligned-joint

See the light under the straight edge of the square? This means the joint is misaligned; there should be NO light under the straight edge. Take a deep breath, and start looking for the cause of the problem. My immediate thought: the table and the clamp plate were not at a perfect 90° angle to each other.

Now I must get ahead of the plan I mentioned near the bottom of an earlier thread. As I mentioned in that earlier post, I planned to cover troubleshooting in Part 5 of this series. But I now chose to ignore that part of my plan, and to give you the benefit of my findings right away. So, let us reason this out together – I will wing it:

  1. I moved the clamp plate several times, to remove and insert clamps as I switched from routing mortises, to routing tenons.
  2. The table moves only on one plane, in the X-axis (left-and-right) and in the Y-axis (front-to-back, and back-to-front). The table is, therefore, a good zero angle reference point.
  3. Both mortise and tenon pieces are machined with the same face facing me (I mark these surfaces with chalk).
  4. If the clamp plate is misaligned, and both tenon and mortise are machined with the work piece clamped flat to the plate, then the error introduced by a misaligned clamp plate (that is, with the clamp plate at an angle other than 90° ) is essentially doubled. This means that a 1° misalignment of the clamp plate relative to the table will result in a 2° misalignment of the joint. And even such a small error will be blatantly obvious.

Question: Why is the error doubled, as I mention in #4?

Answer: It is doubled because the top faces on the work pieces in the photo above are facing me while I machine them – let us assume each piece will have an error of 1°; the joint later goes together with the marks on the work pieces facing me. Thus, a 2° misalignment results; this is visible without the need for any measurement. But it is impressive when back-lit, as I have shown in the photo above — and it is a good way to for me to show you the results. Once again, the eye can tell and it can see the results of a slight joint misalignment; trust your eyes, and check joint alignment, always.

Solution: Align the clamp plate such that is at 90° to the table.

How to do this: My Wixey Digital Angle Gauge to the rescue. Simply set the clamp plate surface 90° to the table surface every time that the clamp plate is moved. First, the table is made the 0° (zero degree) reference surface:

table-zeroed

Then set the clamp plate at a perfect 90° to the table:

clamp-plate-90-deg

After routing the tenon and the mortise, the result is a perfectly-aligned joint when the clamp plate is set to 90° to the table:

well-aligned-joint

I double-checked, and my eyes were correct; I believe you can also tell that this joint is perfectly aligned, by simply looking at the photo above. Trust your eyes, but confirm it with a straight edge — always!

As I kept trying different things, I ran into the following – and when it happened, I felt serious vibration on the router itself, like a strong shudder:

ouch-table-loose

A little more troubleshooting revealed that I forgot to properly tighten the table; I had moved it to align a new work piece.

Edit to add: In addition to remembering to tighten the table, I suggest you also move the table as far left (or as far right) as possible, while still allowing sufficient space to route the mortise. This allows you to move the work piece closer to the clamps; the net result is that the mortise work piece will be better supported by the clamps, and less prone to vibration. And, before I forget, always use two clamps to support the work piece.

After resetting the table, and properly tightening it, I got the following result:

good-mortise

I will continue work on the drawers, aiming to finish them this week. Then on to the rest of that project. And, in between, a little more work with the Super FMT. Hang in there with me!

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—— Al Navas

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Filed Under: Blog, Education, Joinery, Leigh jig, Mortise, Super FMT, Tenon Tagged With: , , , , , ,

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