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View Full Version : sharpening cold saw at home



Tony
08-19-2011, 07:53 AM
Morning all.
'while-a-go i picked up an old cold saw works great i have two blades
(10" OD or so x 1/8" thick HSS) that I keep in rotation (pun intended)..
use one while the other is out getting sharpened. There's a local guy
(saw mill) who "has a guy" that sharpens these for about $15 each.

Does a good job, I must say.

But I'm going through my saws a little faster than I like.. and am considering
sharpening them at home.

has anyone used one of these sharpeners? its a HF model:
http://www.harborfreight.com/120-volt-circular-saw-blade-sharpener-96687.html

I figure it'll probably be junk but might make a good starting point, give
me something to 'beef up'.

I've never played hands-on with one in their store.

-Tony

Forrest Addy
08-19-2011, 10:30 AM
Might be able to do something with it. You gotta remember that a cold saw is a precision milling cutter that happens to look like a plain ol' saw. If I was sharpening a cold saw I'd use a sharpening jig or a tool and cutter grinder equipped with a CBN wheel. It's a long way around a cold saw and I doubt if an AlO2 wheel will hold up a full revolution.

Before you leap into sharpening at home, I strongly suggest you find a sharpening shop and look at the rig they use for cold saw blades. What are there? 100 teeth? What's your time worth?

I suggest you add a couple of blades to the ones you're using in rotation. Taking two blades to the shop makes for longer intervals between visits and you'll always have one blade on standby waiting for the one in the machine to poop out.

Scottike
08-19-2011, 10:47 AM
That looks like it would do ok for sharpening the gullet of your blades, but at some point you'll have to true up the OD of the blade, I don't see that capability in the sharpener. Another issue is if the blades have any "set" to the teeth (where the teeth are slightly offset from the centerline of the blade) I know this is common in wood blades and less so, if at all in metal cutting blades, so that may not even be an issue for you. All in all I'd say that the sharpener would be OK for a gentle touchup,
but you'll still have to send them out periodically to have them brought back into spec.

Rosco-P
08-19-2011, 12:07 PM
Seems like it was designed to sharpen circular saw blades (up to 10" maybe?). Wonder if it has enough rigidity? Looked at the manual, maybe I missed it. Seems to be nothing to control the amount of metal ground from each tooth face. That operation requires some type of precision in-feed control. As already mentioned, no facility to joint the blade, which would be the first step in resharpening a wood cutting blade.

Tony
08-19-2011, 01:36 PM
you know when you read something sometimes and you hear the
sound of wisdom? Thats what I heard reading Forrest's reply.

yes this blade is very much like a milling cutter. the geometry isn't
the same for every tooth.. every other tooth is relieved (10 degrees?)
on each side. there is no set. in between those are just "straight"
teeth.

Forrest Addy
08-19-2011, 02:03 PM
yes this blade is very much like a milling cutter. the geometry isn't the same for every tooth.. every other tooth is relieved (10 degrees?) on each side. there is no set. in between those are just "straight"
teeth.

Aha! It's a triple chip grind. The straight across teeth are a couple thou below the beveled teeth. The beveled teeth take about 1/2 the available kerf from the center and the straight across teeth sweep out the remainder. Each tooth takes out half the chipload and since the chips are narrow there's less interferance in the gullet. It's an excellent design ensuring zero lateral force on the blade resulting in very smooth cuts.

A triple chip grind would be almost impossible to periphery grind with the Harbor Freight gadget. You could sharpen back on the face but you'd only get about 3 grinds before you ran out of profile and got into the secondary relief..

Tony
08-20-2011, 03:25 AM
Forrest, correct me if I'm wrong but I'm picking up the vibe that I
won't be able to do this with my chainsaw file.

:)

Off to (bargain) hunt for more blades... Thanks again all.

-Tony