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3tpi rip saw sharping ?

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shim20

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ive got a disston rip saw the one with the thumb hole, all the teeth are there and even etc, but i want to sharpen it, dose anyone know what saw file i would need as there big teeth, and also how much set to put on the teeth? i want to get it done for a project coming up were im only using hand tools.
any help would be great :)
 

Cheshirechappie

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By the sound of it, the biggest sawfile you can find! Make sure it is a sawfile, though, and not an engineer's threesquare. You need the rounded bottom to the gullets that a sawfile leaves to avoid the possibility of cracks developing in the metal, which can happen at sharp internal corners, which the threesquare will leave.

On set, the usual advice is as little as you can get away with. Set to give a kerf little wider than the blade is thick to start with, say about 50% wider, especially if the blade is taper ground. The less waste you have to remove the easier the saw will be to use, especially for any length of time. If the saw doesn't like minimum set, you can always increase it a bit, but squeezing metal back the other way once it's been bent one way may result in teeth breaking off. Try to set just the tips of the teeth rather than bending the whole tooth as well, so that subsequent jointings and sharpenings will take you back to unbent metal.

Try it and see - that's the best bet.

Edit to add - a bit of rake on the teeth will help a lot. I had a new ripsaw that had no rake at all, and it kept jamming in the cut - far too aggressive. Somewhere between 5 and 10 degrees of rake seems to work much better.
 

bugbear

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shim20":2glxnhqr said:
ive got a disston rip saw the one with the thumb hole, all the teeth are there and even etc, but i want to sharpen it, dose anyone know what saw file i would need as there big teeth
You want a file whose faces are twice as long as the face of the teeth you're working. This is so that all 3 corners of the files are usable without re-using any part of the file surface.

In the case of 3 tpi, that's roughly 1/3 * 2 = 2/3" or roughly 16mm across

BugBear
 

Phil Pascoe

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Depending on the condition of the saw, it might pay to partially file the teeth then top it- it's a bit easier to get the teeth even on the second filing.
 

bugbear

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phil.p":fvynog0l said:
Depending on the condition of the saw, it might pay to partially file the teeth then top it- it's a bit easier to get the teeth even on the second filing.
Yeah - if the teeth are REALLY bad, I find a sequence of "partial topping, filing" operations easier to control than trying to go from awful to perfect in one hit.
 

Cheshirechappie

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That looks like the right sort of thing.

Two other possible sources are Cromwell Industrial Tools, who list a Kennedy 8" (best found by typing 'saw file' into the search facility on the website homepage) and Toolbank.com, who list the most comprehensive range of sawfiles I've seen anywhere. The Nicholson 8" regular has a quoted side width of 19/32", which is pretty close to Bugbear's calculated 16mm requirement, and it's a bit cheaper than Flinn Garlick as well - though I'm not sure how that's affected by minimum order sizes and postage charges.

There may well be other sources as well. I haven't been able to find any sawfiles larger than 8" regular anywhere though, so I suspect those are the largest in current regular production.
 

AndyT

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If you are buying saw files without seeing them, this blog post by Paul Sellers may be worth reading - in offshoring manufacture of their files, Nicholson seem to have forgotten what they are used for, and why subtleties of the design of a saw file matter a lot.
 

Cheshirechappie

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AndyT":wvdbr0ma said:
If you are buying saw files without seeing them, this blog post by Paul Sellers may be worth reading - in offshoring manufacture of their files, Nicholson seem to have forgotten what they are used for, and why subtleties of the design of a saw file matter a lot.
Oh f-f-f-fiddlesticks. That's another previously reliable name we can't trust anymore. But thanks for the warning, Andy.
 

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