Ever get a saw you couldn't file?

[David Weaver]

I got a disston #7 this past week, I figured it'd be a good saw for me to cut down into a panel saw - 10 points crosscut and 26" long, lots of plate, plenty to cut down and file in another nib.

So I got it out, and it felt like ice when I was trying to joint it, dinged up the bastard file I used to joint it. It can be filed on the very ends, but in the middle, nothing - file won't touch it. If you insist on ruining the file, the saw and the file are a pretty close contest regarding which is tougher, ruined a simonds saw file instantly.

Has anyone ever seen that? The plate is pit free, but has a varnished look or tempered color and some staining, same straw color you'd have if you tempered steel by color. I can't see any etch on the plate to confirm that it's actually a #7.

Contemplating a diamond three-square machinists file to sharpen it and then use it, anyway if I can manage to get it sharpened. It sure wouldn't wear quickly.

[harry strasil]

Only time I ever came close to what you have is a HD nail saw, thick plate, 14 tpi, no fleam, no set.

[george wilson]

You will probably also ruin the diamond file. The diamonds will most likely become dislodged before you do more than a few teeth.

File only very lightly with any diamond product. The narrow width of the saw teeth will hasten the diamonds coming loose.

[harry strasil]

If you are lucky enough to find a file from long ago, the files from the past were made of about 10104 or what they called 104 points of carbon, the newer files may be 1095, if you can find a supplier of industrial files, they often are 10100 the same as timken bearing races.

[george wilson]

Actually,David,if the saw is that hard,you will break off the teeth trying to set them. I think it might be best to not use it at all If I HAD to sharpen it,I'd dress a grinding wheel to tooth form,and make a jig to evenly GRIND the teeth. No cure for setting a saw that hard,though.

[Roger Davis IN]

Is it something like a Disston No. 240? That one was filed rip, but was made (and marked as) for cutting metal. I think the metal cutting saws were heavily tapered and used without set (IIRC).

[Marv Werner]

David,

You might try a new double cut file and bare down hard on it as you file. You have to force it to cut. Make sure the gullets are just barely clear of the vise jaws. You need a vise that clamps the blade tight and even. You don't want any vibration going on.

You might end up with a saw with zero set. Do the teeth look as if they have set in them now? If so, when you reset them, make sure you set them in the same direction they are now set and give them very little set.

Before you set them though, hold the blade in the light just right so you can sight down the side of the blade from top to bottom so you can see if the teeth protrude out from the blade at all. Do this on both sides. If there is some set and they look to be the same on both sides, leave them as they are and just lightly side joint both sides. Then do a test cut.

Marv

[george wilson]

I HOPE David doesn't BARE down on the saw!! I assume he's wearing clothes while doing it!

[Marv Werner]

I'm going to take that as a joke, I just hope David does too....

[David Weaver]

David,

You might try a new double cut file and bare down hard on it as you file. You have to force it to cut. Make sure the gullets are just barely clear of the vise jaws. You need a vise that clamps the blade tight and even. You don't want any vibration going on.

You might end up with a saw with zero set. Do the teeth look as if they have set in them now? If so, when you reset them, make sure you set them in the same direction they are now set and give them very little set.

Before you set them though, hold the blade in the light just right so you can sight down the side of the blade from top to bottom so you can see if the teeth protrude out from the blade at all. Do this on both sides. If there is some set and they look to be the same on both sides, leave them as they are and just lightly side joint both sides. Then do a test cut.

Marv

They have plenty of set. they look like they are as-from factory. Someone used the saw some and made it mildy dull. I'll bet they tried to sharpen the saw and set it aside.

I have some second-cut files that I've been wondering if I'll ever use them. I'll get them a shot at this.

I don't mind peculiarities, I guess, I just wish they were on someone else's dime and someone else's time

The old sheffield saw I showed the other day is a hard saw, but it can be filed. I kind of expected it from that saw given its age, but for this one to be a lot harder than that yet, I didn't expect it!

Were disston saws breasted when new? This one is.

Whatever did the teeth last time (set and sharp) was a machine.

Might be an interesting exercise to anneal a worn out file, then file its teeth off and see if I can embed some 100 grit loose diamond in it and try it on this.

I really should just throw it away, but I paid what I'd consider to be a lot for a #7 with a tote that's in bad shape ($30) because it was a full plate and a tooth count that I wanted.

[harry strasil]

I never saw a saw saw, like that saw I saw saw down in Arkensaw.

[David Weaver]

I'm going to take that as a joke, I just hope David does too....

I can imagine explaining things at the hospital.

"Doc, they told me that I had to use this type of file in the buff and the saw slipped out of the vise....


... i swear."

[Marv Werner]

David,

Yes, the better saws were breasted from the factory, some as much as 3/8". Your saw being breasted, you will have to lower that area of the tooth line down lower in your vise so the gullets are barely above the vise jaws. Make sure your vise is sturdy and doesn't move as you force that file to cut. You mentioning the blade being breasted gives me a glue as to why it is harder to file in the middle area. The teeth are not being supported as well and are vibrating.

With the teeth having plenty of set, it should be relatively safe to reset them if you need to. Most saws I get, will usually have too much set.

Marv

[george wilson]

David,a fine cut file will cut harder steel than a coarse cut one. If you have been using a bastard file,a switch might be in order. IF that saw has been set without the teeth being broken,which you just revealed,perhaps it's your coarser file that is a problem.

Old new stock triangular files are among the easier type files to find. Keep a lookout for them. Harry has a point.

[Jonathan McCullough]

Can't really say I've run into a saw like that. I wonder if they didn't temper it correctly. Given the millions of saws they must have made, isn't it possible?

I try to not joint saws if I can avoid it, but when I do, I joint to get it flat, then do strokes forward starting at the middle and going toward the toe, then an inch forward of the middle and going toward the toe, then two inches from the middle, etc., repeat from the middle to the heel, etc. to get a little belly on the saw.