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View Full Version : So, you always wanted to build handsaws...slotting fixture...



Alan DuBoff
11-18-2008, 7:11 AM
Been a fair amount of saw making on this fora, good to see!:cool:

I thought I would post this, even though saw making involves a fair amount of metalworking, and you will see that I was doing just that this past weekend.

First, how about a little background...because most handsaws were made with a folded back for more than a couple centuries, until about a dozen years ago when Pete Taran started to slot the backs out of brass. Some folks still prefer a folded back, so a slotted back is not for everyone. Others prefer the slotted back, it's all really a matter of preference.

There's been much written about the sleek design of the slotted back, it really does produce a nice looking tool, IMO, so I won't bore folks with too much detail...suffice to say that this is a modern design that has only been done for about a dozen years. I guess this is to say that slotting the back is not a traditional method, but a handsaw is still a traditional tool...;)

I'm sure that each maker of such slotted backs has their own way of slotting them, and I will show you how I plan to do mine as I spent the weekend building this fixture to hold metal so I can slot it on my Nichols horizontal mill. A horizontal mill is actually the preferred machine for slotting handsaw backs, although some will argue that similar work can be done on a vertical mill, I prefer the prior. This fixture will hold the stock vertical, so that it can be slotted with the overarm and horizontal arbor.

My intention with this design was that I would have no obstruction above the top surface of the fixture, since some blades are only available in small diameter, such as 2 3/4". This is not a problem with a small arbor used on vertical mills, but a horizontal mill has a 1" arbor, and the spacers take another 1/4"-1/2" more...this doesn't leave much depth to cut, so if you have bolts/clamps above the surface of the fixture, it will limit the cutting ability of the mill and in this case probably completely. This will only leave me with about 5/8"-3/4" cutting depth under the arbor/spacers. So, clearance is tight. That is enough for what I need, providing I have the clearance.

This fixture will slot up to 19"-20" in one pass, so should be excellent for most backsaws, only the very largest being a concern, and one can reposition the stock if needed...just easier to not be forced to do that.

(linky pic)

http://www.softorchestra.com/images/slotting-fixture.jpg (http://www.softorchestra.com/metal/slotting-fixture/)

Stay tuned for my next saw, but it will probably take me a couple more weeks. I'll try to slot the back this coming weekend, possibly make the handle. If I focus on it, I can finish a saw in a day.

Dave Anderson NH
11-18-2008, 1:59 PM
I am envious of your selection of metalworking machines and the obvious fact that you evenhave the space to put them. I won't complain too much though since I have access to a Bridgeport, 2 surface grinders, a metal cutting bandsaw, oxy-acetylene and mig welding gear, and a 16" x 48" engine lathe at work.

I look forward to your continuation of this post with as many more pix as you feel you need.

Alan DuBoff
11-18-2008, 4:34 PM
Dave,

I don't have very much metalworking machinery, fairly sparse compared to woodworking...but my mill is pretty flexible. It also has a vertical head that I don't have in full operation yet...I don't have very much space at all, and need to move things around and move my car out of the garage to use them.

I have been pondering how I could setup the garage better, get rid of a couple things that are not being used, and create a more usable space, kinda like "The Not So Big House", if your familiar with that concept.

The great thing about the Nichols is that it only takes up about 2 feet by 3 feet of floor space, so it fits into a pretty small space, at least for a 1200# hunk of iron. Quite amazing when you consider it was built in '44 when steel and iron was at one of the all time lows in America while they were building for the war. I love WWII era machines.

I have a small South Bend 9A that came out of the Levi Strauss factory, and another small mini-mill, but that along with my tooling is the extent of my metalworking machines (albeit I do have some blacksmithing tools :) ).

I do like how things have been headed with my space at home, I have all the power tools/machines in the garage for the most part, and only hand tools out in my shed/office. The concept is dimension with power, join/assemble/detail by hand. Aside from cutting out the handle shape on a scroll saw, the handles are all done by hand with rasps, shaves, knives, etc...

Attached is what the results looks like, that was the last back I slotted out of bronze. I have some dimensioning to do on a piece of brass to slot it for the next saw, so couldn't get that done this past weekend.

I confess, I'm not nearly as competent of a toolmaker as yourself, but I'm trying! ;)

Johnny Kleso
11-18-2008, 8:10 PM
Alan,
I would only clamp the blank not more that 1/8" above that will be the unslotted section of the blank..

Your fixture might pinch the sides in after the cutter slotted several inches..

If your going to chamfer the blanks I would do this before slotting...

Looking foward to see how it works, I might have to trade you some brass for some sloted blanks :)

Alan DuBoff
11-18-2008, 10:12 PM
Johnny,

What I learned on the last fixture was that I had used 5/16-18 cap screws and the diam. prevented the ability to have the top without clamping pressure from the screws.

On the old fixture the depth of the slot was 3/4", so if you were to slot a 1/2" wide back, there was little if any that was not under tension when clamped in the fixture.

To eliminate that problem, I made the slot only 5/8" deep on this, and used smaller 1/4-20 cap screws. The screws are almost in the bottom of the slot, so the tension is only on the bottom of the slot, allowing as much to be clear of tension for slotting. You can still slot if the tension is against the area being slotted, but that is not ideal, IMO.

On this new fixture there is nothing above the top surface, no bolts, no strap clamps, nothing. The large slots in the ends seem like they will hold the fixture plenty tight for slotting brass and bronze.

If your going to chamfer the blanks I would do this before slotting...
I have only done chamfering with by draw filing it. I have a cutter that has a 45 degree angle on both sides, the idea is that I would use it, but haven't gotten around to it yet. For that I might need a very shallow slot in this fixture, or use a vise with parallels.

Looking foward to see how it works, I might have to trade you some brass for some sloted blanks :)
Could be a possibility if you make it bronze! I'm a bearing bronze junkie!;)

Johnny Kleso
11-19-2008, 8:47 PM
I have two sheets of brass 1/4" x 12" x 48" that I paid $100 each for and the seller had six more but I couldnt afford them..

Bronze is hard to come by at ebay these days I have been checking every week for some 1/2" for lever caps and no luck this year at all :(

Alan DuBoff
11-20-2008, 3:06 AM
Johnny,

Those are pretty big sheets of brass, would hate to see the shipping charges...:o

You can get 1/2" bronze rod from Enco reasonably, in 12" lengths. I love working bronze, it is my favorite so far.

I have some 1/4" brass I got at SIMS (recycler), they charge about $2.50/lb, or about half the cost of new. I got a couple bars that are 1/4" thick x 1 1/2" wide, by about 24" long. The problem with this type of stock, and more so the sheets you have, it's the time it takes to prepare the material that is a time sync. It's cheaper or me to buy stock reasonably close to what I want. In the case of brass, 360 is available in most sizes I would need. For the bronze I don't have much choice, for the smaller size it needs to be milled down.

I guess you could cut those sheets on a band saw, but unfortunately I only have a wood cutting band saw. I have heard folks cutting brass on them though, I haven't done it myself as I don't have a blade.