Milling wood saw blade steel

I'm trying to design a sharpening jig for my bandsaw mill blades that uses a
hand-held Dremel as a cam-guided router. I think I know how to make the
positioning fixture, and mill a cam to guide a bearing on the bit shank, but
I have no experience with milling moderately hard wood saw blade steel, or a
worn-out blade to practice on. Presumably the choices are ceramic or diamond
grinding bits or HSS or carbide milling cutters. The gullet curve has a
minimum radius of 3/32" which I'd like to preserve by using 1/8" or 3/16"
cutters so the blades can still be resharpened without difficulty on
commercial equipment.
The cam milling setup would be a pin the diameter of the cutter bit clamped
upright on the milling machine table, centered under an endmill the diameter
of the routing bit shank bearing OD, like 0.500. I have a short section of
new blade to clamp under the cam blank to trace the gullet shape against the
lower pin, and once the straight front and top rake sections have been
started they could be extended beyond the tooth tip by clamping the blank at
the 30 or 8 degree rake angle and moving the table. The limitation is that
there's no way to adjust for wear on the bit beyond moving it endwise in the
collet, thus an HSS or carbide cutter should be better than a stone IF they
hold up long enough.
The teeth have to be set sideways and perhaps reset to the opposite side so
they are are soft enough to file, which I just confirmed. My Scleroscope
doesn't measure the Rc hardness of objects less than ~1" thick reliably even
if they are solidly clamped in the milling vise. I checked it against
samples of known hardness while taking blacksmithing classes.
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The shop that sharpens my blades told me they recently replaced some old
equipment, so maybe the problems I'm having will be gone when my resharpened
blades arrive next week.
Reply to
Jim Wilkins
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uses a hand-held Dremel as a cam-guided router. I think I know how to make the positioning fixture, and mill a cam to guide a bearing on the bit shank, but I have no experience with milling moderately hard wood saw blade steel, or a worn-out blade to practice on. Presumably the choices are ceramic or diamond grinding bits or HSS or carbide milling cutters. The gullet curve has a minimum radius of 3/32" which I'd like to preserve by using 1/8" or 3/16" cutters so the blades can still be resharpened without difficulty on commercial equipment.
clamped upright on the milling machine table, centered under an endmill the diameter of the routing bit shank bearing OD, like 0.500. I have a short section of new blade to clamp under the cam blank to trace the gullet shape against the lower pin, and once the straight front and top rake sections have been started they could be extended beyond the tooth tip by clamping the blank at the 30 or 8 degree rake angle and moving the table. The limitation is that there's no way to adjust for wear on the bit beyond moving it endwise in the collet, thus an HSS or carbide cutter should be better than a stone IF they hold up long enough.
side so they are are soft enough to file, which I just confirmed. My Scleroscope doesn't measure the Rc hardness of objects less than ~1" thick reliably even if they are solidly clamped in the milling vise. I checked it against samples of known hardness while taking blacksmithing classes.
old equipment, so maybe the problems I'm having will be gone when my resharpened blades arrive next week.
While I don't have direct experience I can refer you to YouTube where there are a few bandsaw mill blade sharpening videos. A few show commercial sharpening systems that I found to be very educational. Most seem to us a diamond blade or wheel. The time per tooth for basic carbon or even HSS teeth is very short.
I think a simple ratchet dog and a quick clamp would work for indexing. Set the angles for your sharpener twice per simple blade. Once for left set and once for right set. Due to varying blade lengths the tooth count may not come out even so always remember to paint/mark your blade so you don't start accidentally reverse sharpening teeth when you get to the end.
For my upright and horizontal bandsaws I have pretty much decided that sharpeni8ng is not worth my time when I can buy M42 blades made to length. If I had a large gap (low pitch) bandsaw mill blade I might be tempted to sharpen. I do have one carbide tooth blade that might marginally be worth sharpening instead of replacing... and its dull.
Reply to
Bob La Londe
uses a hand-held Dremel ... --------------------------- While I don't have direct experience I can refer you to YouTube where there are a few bandsaw mill blade sharpening videos. A few show commercial sharpening systems that I found to be very educational. Most seem to us a diamond blade or wheel. The time per tooth for basic carbon or even HSS teeth is very short.
I think a simple ratchet dog and a quick clamp would work for indexing. Set the angles for your sharpener twice per simple blade. Once for left set and once for right set. Due to varying blade lengths the tooth count may not come out even so always remember to paint/mark your blade so you don't start accidentally reverse sharpening teeth when you get to the end.
For my upright and horizontal bandsaws I have pretty much decided that sharpeni8ng is not worth my time when I can buy M42 blades made to length. If I had a large gap (low pitch) bandsaw mill blade I might be tempted to sharpen. I do have one carbide tooth blade that might marginally be worth sharpening instead of replacing... and its dull. --------------------------
Thanks. My 4G LTE Internet was absorbed by another ISP who offered me a nice introductory rate of $4 per GB for a while, but has reverted to their normal $10/GB rate, so I try to stay below 50~60 MB per day and avoid videos, at least until I finish the outdoor projects and can take time to use the town library's WiFi. I've looked at several text + photos descriptions of home made blade sharpeners.
If I decided to sacrifice the factory gullet shape I could mill a blade holding fixture for my chain saw sharpener to grind only the straight front rake (hook). I think the commercial sharpener sets the teeth left, center, right first and then grinds them all the same way, a straight-across rip grind instead of an angled cross-cut like a hand saw.
The tooth pitch is a large 3/4" and the 3 tooth set pattern makes keeping track of where I am pretty easy. I've already deburred and reset two poorly done blades, the reason for considering making a sharpener. It's easier with the blades on the saw which holds them more firmly than my hand wants to. The weld is an obvious starting and stopping point where the pitch is uncertain, a consideration for indexing the teeth from adjacent ones to leave the gullet open for the cutter.
The real question which I didn't state explicitly was whether or not the cutter types I listed can cut fileable spring steel with a reasonable life.
Reply to
Jim Wilkins
A Dremel moto tool would be a poor choice for this aplication. I say this because I just made up a half dozen blades for my 12" band saw (wood) by silver soldering new and used 1/2" bade stock. I grabbed the Dremel to clean up the joint after it cooled. On the second blade I tried a mounted stone in my el-cheapo air powered die grinder and finished off the five remaining blades in less time than it took for the first blade. The Dremel just doesn't have the oomph that the die grinder packs, plus the 1/8" spindled stone is about a quarter or less the mass of the 1/4" mounted die grinder item. How did I ever live in my shop before I got my old Gardner-Denver compressor for $3 and spent ~$75 to get it up and running!
Reply to
Gerry
A Dremel moto tool would be a poor choice for this aplication. I say this because I just made up a half dozen blades for my 12" band saw (wood) by silver soldering new and used 1/2" bade stock. I grabbed the Dremel to clean up the joint after it cooled. On the second blade I tried a mounted stone in my el-cheapo air powered die grinder and finished off the five remaining blades in less time than it took for the first blade. The Dremel just doesn't have the oomph that the die grinder packs, plus the 1/8" spindled stone is about a quarter or less the mass of the 1/4" mounted die grinder item. How did I ever live in my shop before I got my old Gardner-Denver compressor for $3 and spent ~$75 to get it up and running!
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I recently used a Dremel to grind car fender rust spots back to solid metal, by feel. The stones had a very short life cutting into the edge of sheet metal, and a chainsaw sharpening stone disintegrated on it. I didn't have a cylindrical HSS cutter bit to try. The Dremel was very slow grinding down the back of lumpy old welds in the narrow gap between the fender and wheel well liner, where the larger bits of my 1/4" die grinder wouldn't fit.
1/4" bits are certainly an option, I have several air and electric tools that accept them, for grinding welds in tight corners etc. I started planning around a Dremel because I have one with the conical routing guide attachment, and its lighter weight should make it easier to guide accurately. A 12V chain saw grinder with a 3/16" cylindrical diamond bit might work too, with a suitable router guide, if the bit doesn't wear too quickly.
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A 1/4" cutter changes the gullet minimum radius and may disqualify the blade from commercial grinding. The real question is what easily available type and size of bit should I design for. I don't have a scrap blade to test cutter bit life on.
Reply to
Jim Wilkins
here you go...
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Reply to
wws
a nice introductory rate of $4 per GB for a while, but has reverted to their normal $10/GB rate, so I try to stay below 50~60 MB per day and avoid videos, at least until I finish the outdoor projects and can take time to use the town library's WiFi. I've looked at several text + photos descriptions of home made blade sharpeners.
blade holding fixture for my chain saw sharpener to grind only the straight front rake (hook). I think the commercial sharpener sets the teeth left, center, right first and then grinds them all the same way, a straight-across rip grind instead of an angled cross-cut like a hand saw.
keeping track of where I am pretty easy. I've already deburred and reset two poorly done blades, the reason for considering making a sharpener. It's easier with the blades on the saw which holds them more firmly than my hand wants to. The weld is an obvious starting and stopping point where the pitch is uncertain, a consideration for indexing the teeth from adjacent ones to leave the gullet open for the cutter.
the cutter types I listed can cut fileable spring steel with a reasonable life.
Diamond circular blade in jigged up angle grinder or more purpose built grinding drive.
Reply to
Bob La Londe
Diamond circular blade in jigged up angle grinder or more purpose built grinding drive.
--------------------------------------------
One of the sites I visited had gone to that after the stones failed.
One file stroke per tooth is quick and gives a noticeable improvement.
Reply to
Jim Wilkins
One file stroke per tooth is quick and gives a noticeable improvement. ---------------------------------------
If filing the 30 degree top of the tooth proves to be effective and acceptable to the resharpening shop, the guide could be similar to the Husqvarna roller guide which indexes solidly on the chain. I begin problem-solving with complex solutions but often end up with simple ones.
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Reply to
Jim Wilkins
Well, I recently had to sharpen a saw blade. It wasn't a bandsaw blade, but it was probably similar. An old school 24" butcher's saw. It looks like an oversized hacksaw. It was dull from use, and it has lost much of its set, but there is still some. I just free handed it under a magnifier lamp with a cheap diamond blade mounted on a bench grinder. By cheap I mean a piece of thin steel with a thin coat of diamond dust glued to the sides. Harbor Freight sells them for $8-10 but I have a buddy who buys them elsewhere in bulk to sell with a tungsten sharpening kit on Ebay. Anyway, I just sort of picked an angle and set my hands up with a few practice dry runs for some short term muscle memory. I would not say it worked "great" but it worked well enough.
The saw is nothing special. At one time probably every store with a meat department had one, but my mom used this one to breaking down sides of beef that were to big to put on the bandsaw. 30-40 years ago. A couple years ago I asked my dad if they still had that saw, and if they would look to see who made it so I could buy one. A few weeks later be brought me the saw. (They have been out of the grocery business and retired for a few years now.)
Before the holidays my wife picked up several sections of standing rib roast. They were on sale everywhere. One store cut them into steaks for us at no charge, Another no longer does that so I was stuck breaking them down by hand for vacuum sealing and freezing. The first two cuts before sharpening just about wrecked me. After sharpening I was able to break down sections with a knife and cut the bone twice as fast as my wife could vacuum pack the individual steaks.
Then a few days later I found I could buy those blades online still. I don't think I'll resharpen this blade again. LOL.
Reply to
Bob La Londe
Bob La Londe on Fri, 8 Jan 2021 07:56:22 -0700 typed in rec.crafts.metalworking the following:
Cool. I have become Carver Of Meats in our house. Not as elaborate as your procedure, but 'Honey if you'll carve the roast, we can eat.' makes for a nice "chow call."
Yep. I had a lawnmower blade that was dull. Okay, blunt where it wasn't "nicked". Mentioned this to Carlin and he pointed out that when he ran a landscaping business, he bought lawnmower blades by the package. Cheaper to replace a blade than lose the downtime to sharpening one. I decided that rather than spend a day (or two) sharpening a blade to save a few buck, just go get a new one at the hardware store.
Like wise, Cliff when he was running the family heavy equipment company, had a policy that if they had to 'crack the case' of an engine, replace all the bits which wear - bearings, rings, etc. Because if he didn't, something would give in the middle of a contract, and it was much less expensive to replace "good" bearings, than stop work.
OTOH, for some things, learning to sharpen them is a skill to master. E.G. chisels and plane blades.
Reply to
pyotr filipivich
For some years now I've been sharpening my mower blade at the start of the season as it cuts the long grass so much better. I find it only take a few minutes with my small air belt sander with the mower tipped on its side and the plug lead removed for safety.
Reply to
David Billington
I keep 4 sets in rotation for my mowers. In the spring they all get sharpened as needed then I swap out the dull or damaged blades, then touch them up and put them back on the rack. There used to be hard faced blades available for the two larger decks but they really were not worth the money as the edges tended to chip and crack rather than just mushroom if you hit anything.
Reply to
Steve W.
"Steve W." on Sat, 09 Jan 2021 12:47:52 -0500 typed in rec.crafts.metalworking the following:
And there is another option: sharpen them all on your schedule, then replace as needed.
Reply to
pyotr filipivich
David Billington on Sat, 9 Jan 2021 16:34:41 +0000 typed >> Bob La Londe on Fri, 8 Jan 2021 07:56:22 -0700 typed
I have one of the "single level to adjust all four wheels" mowers, but the shroud is shot. OTOH, I spent more on new control cables than for the mower (it was a free find by an friend of mine.)
As I did not (still don't) have a belt sander, that wasn't an option. Then again, I had a tendency to ignore it till the buttercup was too high for a mower - weed whacker and 'clear cut' the 'back forty'.
Like I said - to each his own. I mean it isn't like I'm replacing the whole mower instead of just the blade.
Oh yes, and mower blades can be used to make plane blades - regular or shaped for a molding plane. All depends on where you want to invest your time.
Reply to
pyotr filipivich
You mean adjustable blades for aircraft engines?
Reply to
bruce bowser
No, like the wood shaping tool called a "plane".
Elijah ------ the flat ones make planes (math sense) out of wood
Reply to
Eli the Bearded
No, like the wood shaping tool called a "plane".
Elijah ------ the flat ones make planes (math sense) out of wood
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Adjustable blades on an airplane engine nearly killed Howard Hughes.
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Reply to
Jim Wilkins
Nowadays, the FAA (Federal Aviation Administration) certifies them, like with Hamilton-Standard's Ground Adjustable Prop.
Reply to
bruce bowser

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