Saw Construction 2 - Folded Back Prep
By D. Greco
Winter 2014


As with the saw plates we sell, the folded backs need a bit of work before they are installed. All of the backs are supplied in even lengths and need to be cut down to length to work with your individual saw handles.So really it's all a matter of how long your saw plate is and how far the mortise for the saw back extends into the handle. For this example I'm using an old Disston backsaw handle I had on hand. But you should be able to apply this technique with a newly made handle.




As I mention above the first thing you need to know is that the back is almost NEVER as long as the saw plate. It almost ALWAYS is cut down by a bit. If you are installing the back into an existing handle you are one step ahead of the game. If you are installing the back into a new handle, then you need to look at the profile and determine how far the back will extend.

Let's take a look at the Disston D-4 backsaw handle template from our library here.



As you can see from the image above, the saw back extends into the handle. You need to take this into account when you determine the length.

But like I said, for purposes of this article (and because it's the only one I had on hand at the moment) I'll be using this old Disston handle (shown below)



To get an idea on how much we are talking about I will usually lay out the parts one on top of another and mess with their orientation until I arrive at what I feel is the "right look"




If you look at  the photo above you can see where I used a black magic marker to outline the radius on the right end of the folded back as well as the cut line for the left end at the handle mortise. One thing I need to add here. When cutting these saw backs down, I tend to err on the side of caution. I'd rather cut it a bit too long and need to trim it rather than cut it too short and possibly ruin it.

Cutting the steel or the brass backs is not terribly hard to do. You can go all "old school" on them and use a hacksaw, or if you have a metal cutting blade for your bandsaw, use that. Either way, mark a line with a straight edge or square and try to stay to the "waste side" of the line. While it will make less work for you, don't worry too much about a super clean cut. the next step will clean up the edge.



If you have a disc sander use the miter gauge to ensure you get a nice perpendicular edge (shown above). Otherwise, you a file and creep up on the line you marked.



Now it's time to address the rounded portion. And once again I turn to my disc sander (no pun intended). But you can use a file and accomplish the same job.



After you've completed these tasks I would suggest that you clean up the edges with some 220 / 300 grit sandpaper. Because it will be highly visible, I recommend that you pay particular attention to the rounded area. Just remove the machining marks and you'll be set.




At this point we need to take a small side trip and look at the saw plate. If you remember from the initial photo shown, these saw plates are rectangular. And in order to fit on this (and just about every backsaw handle I've ever came across) you need to trim the corner of the saw plate in order to fit into the handle.



I used the holes for the saw nuts as well as the end of the saw back to help me locate the position on the saw plate and then establish where I should trim the corner down. I just marked the holes with a pencil and that will give me an idea where the cut should be



The number one question I get from newbies is how to cut spring steel. And I tell each and every one of them that it's really not all that hard. You just need a Dremel equipped with an abrasive cut off disk, a vise and a file to clean up the edge.



All you need to do is score along the line. That means cutting but not going all the way through. Just cut to about half the thickness of the saw plate. Don't linger in one spot or you will burn the steel and it will loose it's temper. Then you clamp the saw plate in your vise and make sure the top of the jaws are right at the scored line. Hold it and SNAP!



After you cut the make the cut you need to file the edge smooth and then remove the burr from either side. I typically use a sanding block on each side and progress up through the grits until the scratches disappear. If you do not do this a burr can cause problems when it comes time to fit it to the handle.
Now that we have the saw plate ready to go, lets resume our work on the folded back.

Look at the base of the folded back where the saw plate gets inserted. What I call the "base" is the area where the two legs come together and eventually the saw plate will get installed. If you'll notice, there isn't a huge gap showing. When we form these backs the press pressed the "legs" together so that they are touching. We'll look into this later in the article. For now, don't worry about it



Now is a good time for you to make yourself a super simple jig that will allow you to work on the saw back and eventually become an aid for installing the saw plate. You just need a piece of flat 2x4 or other scrap that is about 3" wide. It needs to be about 3" longer than you saw back and just over an 1" thick. Use a table saw to cut a groove down the center that is as wide as the folded back. The goal is to have it hold the back with the portion where the blade is installed facing up. Try to make just wide enough so that the folded back just fits in. Either tack a piece of wood onto the end or clamp one in place. This will act as a stop when you start sanding the exposed portion.

Using a sanding block, start with 220 - 300 grit and smooth out the base of the folded back. Once you get it smooth move up in grit and it'll start to shine like a mirror.



Once the base is sanded remove the saw back from the wooden jig and start sanding it. The photo below is just after sanding with 320 grit sandpaper. This brass takes a shine pretty easily and anything past 400 grit will make it look like gold.



Now we are ready to install the saw plate.

There is a small scraper included with each of the saw plates you get from us. If you look closely, you will notice that one edge is rounded over.
Actually it's not a scraper, it's a shim. We use the rounded edge of this shim to open up the legs of the folded back and give us room to insert the saw plate.



As illustrated in the photo above, you insert the rounded edge of the shim in from the end at the rounded portion of the folded back. You then use a small hammer to tap it in and open the gap up (see below).




Once you get the gap opened reinstall the folded back into the wooden jig while being careful not to knock out the shim.






With the teeth of the saw plate oriented correctly (for a Western style push saw) insert the corner of the saw plate into the gap you created. Once you have the corner in use a wooden block to forcefully tap (notice I didn't say BANG) on the edge with the teeth and carefully force the saw plate into the gap.



Once the saw plate in in, remove the shim and try and work the saw plate forward until the corner is closer to the rounded edge. I usually shoot for about 1/8" in from the edge.



By tapping along the tooth line, gradually work you way down the saw plate. You will slowly see the saw plate work it's way into the gap.



As the saw plate becomes imbedded it will become harder for you to force more of it in. At this point you can use a hammer and protect the tooth line with block of hardwood.



Try to shoot for an even amount of the saw plate to be embedded. You don't want to go all the way in and bottom out. You also don't want to only in 1/16". For this case I used 1/4". If you do it right, then you are done.

Now what happens if you find that the saw plate is too far forward or too far back? Well, you need to remove the back and start over. But don't get all worried! This is the reason these folded backs are cool. Provided you do not deform the folded back, you can remove the saw plate somewhat easily.


You need a simple tool to remove the back. I called it a wedge. It's just a piece of hard wood (like hickory or ash) that is about 8" to 10" long and has a wedge shape cut into one end.



If you hold the saw plate assembly in a vise (preferably a machinist's vise like I have shown here), you can use this wedge to direct the force of a hammer blow to push the folded back off of the saw plate. I would recommend that you hold the saw plate assembly "low" in your vise and apply the wedge right above the jaws. This will minimize the deflection that the plate assembly will see. You can also tap from either side of the saw plate.



With forceful taps (not BANGS!) the saw back will slowly work it's way loose. As you move down the saw plate, loosen the jaws of the vise and move the saw plate assembly up. When you reach the bottom, carefully tap and allow the brass back to get to the point where it's just about to fall off. But don't break it totally free.

Here is where you can go back to the wooden jig and attempt to reinsert it as described above.

That's about it. If you have any questions please feel free to email me at Dominic@tgiag.com

Thanks,
Dominic

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