|Project by paratrooper34||posted 07-14-2010 01:53 PM||3650 views||27 times favorited||11 comments|
Hello Fellow LJs!
So I finished my companion Marking Gauge to the Mortice Marking Gauge I made a couple of days ago. This one is made of the same wood, Koa and Paduak, and some brass to compliment the other. This one borrows the tightening knob from another donor gauge previously bought on Ebay. All other hardware is hand crafted. I will explain later.
I started by fitting the wood blanks. The Koa and Paduak fitting/milling was straight forward with the same idiosyncrasies I noted with the other gauge. Try as I might, with smooth plane freshly sharpened and tuned to a slight cut, the Paduak STILL had some minor tear-out. Wow, that wood is really crazy. In the future, I will look at getting as much finished as possible before making final cuts. Or maybe even a small card scraper. I actually tried used my card scraper on this, but it is very difficult to hold it straight enough to avoid ripping out the corners of the beam. So I decided to live with the minor tear-out on this one as I did with the other. I think if I make another, I will use a different wood, maybe ebony or rosewood.
Once I had the wood fitted, I went to work making the hardware. As I said above, the only piece donated from an old gauge was the brass tightening knob. I had to fabricate a brass wedge (more on this later), a cutting knife, and a brass escutcheon for the knob. The escutcheon was easy; I used a brass washer. Because I did not have a threaded escutcheon for this gauge, I needed to make something that would make this gauge look like the mortice gauge I made. That brass washer was perfect for the “look”. For “function”, however, the fence was tapped to accept the threads of the knob. You really cannot tell the difference and I made the threads well to avoid them being torn out. I drilled two small holes on the side of the washer and used a countersink to chamfer the edges for the screws. For the knife, I used an old jigsaw blade. I first broke it down to size. Yes, I said “broke it”. I put it in my vise and snapped it of at the length I wanted. I fyou know of a better way to do this, I welcome your suggestions. Not high tech, but I couldn’t think of a way to cut it. The rest of the rough shaping was easy on my grinder. I started with grinding off the teeth, ground it to size, ground the “Vee” shape of the blade, ground bevels on the blade, and finally ground the round end. I took special care to avoid over-heating as I wanted to keep the temper so the blade would stay sharp once honed. I then took the knife blank to the sharpening station and used a diamond stone to take all the black finish off the blade and honed the knife. All in all, not a difficult operation.
The next step was making the brass wedge to hold the knife in place. I rough cut a piece out of some brass stock I have. I then used a bunch of files to work the wedge down to the shape I wanted. Sandpaper smoothed it out and then a trip to the buffer finished it off. Now, this was a learning process as I never made one of these before. Here is what I learned: the first (yes, the first) wedge I made didn’t lock the knife in place as I thought it would. It never cinched down properly. I determined the reason why was because the wedge was just a tad too short AND the polish I put on the wedge didn’t allow it bite into the wood enough to perform a proper wedging action. So back to the drawing board to fashion a new one. On the second one, I left the area that contacted the wood inside the beam with a rough finish, just as the hacksaw left it. What shows above the beam is polished. Plus I made the wedge, when properly seated, just a hair longer than the blade. This allows me to give a little tap with a hammer to seat the wedge and lock it in place. In hindsight, I think it may have been a better idea to fashion the wedge from wood. I may just make one from wood in the future.
On to fitting the brass pieces to the wood. I started with the fence first. I drilled a hole to fit the escutcheon with my trusty Millers Falls hand crank drill press. I made the hole just a tad deep so I could plane the surface down to meet the escutcheon. It is much easier to do this than to try to make the hole the perfect depth. The fence at this point was still a little big to allow for this. I then routed the rabbet to accept the brass wear strip. The rabbet was made a little deep as well. When fitting brass like this, it is much better to set them a little deep and bring the wood to them. I simply planed the wood to “almost there” and then finished it off by sanding the fence with the brass in place. This ensures both surfaces are on the same plane and it puts the final finish on the brass at the same time. I moved to the beam after the fence. The first step was to make the mortice for the blade and wedge. I figured the angle for the mortice was 5 degrees (that was the angle for the wedge also). I chiseled out the mortice at that angle on one side and 90 degrees on the other. Pretty straight forward as well. I then routed the front of the beam for the brass strips. I initially was not going to put brass there; simply leave the beam completely wooden. But I decided that the brass strip would enhance the look and serve as protection for the wood when the tightening knob was used. To keep a uniform look, I decided to extend the brass on the entire face of the beam. I left a gap for the blade only and it made a nice look. As a bonus, the brass adds some weight to the tool. I also went through the fitting with the blade and wedge, as you read above.
I used a boiled linseed oil finish with a layer of furniture wax above it. I buffed the whole thing on my buffer and assembled the gauge. It was time for a test run. It works great. Nice, clean, crisp lines are left in a piece of cherry (in the picture, the top line is jacked up due to operator error). The beam moves easily and it locks in place with no movement. The redone wedge holds the blade fast and there is no side to side movement when marking. That was important to me as my old Marples gauge didn’t have a secure blade and it felt like I might be losing accuracy with that.
So how much did this one cost? I imagine this one was a little more expensive than the mortice gauge because it has more brass in it. I estimate this one to be somewhere in the three to four dollar range. Now I have a matching marking set that looks pretty nice (if I do say so myself!) and total cost around six dollars or so. These will be passed on to the grandchildren someday (when I get some that is!)
Thanks for reading and I hope this inspires someone to make their own. It is not really difficult to do. If you have any questions, please let me know, I would be glad to help out.