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. http://www.detroitflame.com/HardnessTester.htm
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.
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On 11/4/2020 5:41 AM, Jim Wilkins wrote: > 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. > http://www.detroitflame.com/HardnessTester.htm > > 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. > >
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.
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"Bob La Londe" wrote in message
On 11/4/2020 5:41 AM, Jim Wilkins wrote:

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.
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On 11/4/2020 4:24 PM, Jim Wilkins wrote: > "Bob La Londe" wrote in message > > > On 11/4/2020 5:41 AM, Jim Wilkins wrote: >> I'm trying to design a sharpening jig for my bandsaw mill blades that > 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. >
Diamond circular blade in jigged up angle grinder or more purpose built grinding drive.
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"Bob La Londe" wrote in message

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.
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"Jim Wilkins" wrote in message
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.
https://www.firewood-for-life.com/husqvarna-chainsaw-file-kit.html
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On Wed, 4 Nov 2020 07:41:37 -0500, "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!
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"Gerry" wrote in message wrote: >I'm trying to design a sharpening jig for my bandsaw mill blades that uses

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!
--------------------------------------
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. https://www.ebay.com/b/12-Volt-Chain-Saw-Sharpener/85915/bn_7023355232
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.
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On Wednesday, November 4, 2020 at 6:42:19 AM UTC-6, Jim Wilkins wrote:

here you go...
https://www.youtube.com/watch?v=TEVvd81V7Ms&t20s

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