What are you using to sharpen your scraping tools?
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    Default What are you using to sharpen your scraping tools?

    First a disclaimer: I'm just getting into scraping so take anything I post here with a couple of grains of salt.

    These are some photos of a jury rigged setup for sharpening carbide scrapers and brazed lathe tools that I made. What I would really appreciate is some suggestions on how to improve the current setup into a more permanent form. I have a plated 100 grit 4" cup wheel on the far left, then a 1200 grit charged cast iron flywheel off a DC motor for an exercise treadmill, then another iron flywheel with 3000 grit and finally a 4" 240 grit resin cup wheel on the far left. It all runs off a DC treadmill motor with PWM speed control and small ATX drive belt with surprisingly good balance at all speeds.

    So far it's worked well for rough shaping and fine polishing a 20mm square carbide insert brazed to a 16 inch flat steel bar. I can see the 100 grit plated cup wheel could do with water feed as I've nearly killed it grinding some glass at low speed dry: optometry labs have a wet bench grinder setup with a trough at the bottom of the wheels with a recess for a wet sponge in contact with the grinder wheel to keep it damp and wipe the glass paste off the grinding surface.

    There's already been a few cross contamination issues with the oil/diamond paste picking up the odd particle from the rougher grits so you get a few scratches when polishing that disappear with use. I'll probably replace the 100 grit cup with a 6" plated faceting lap in 120 grit and keep the resin 240 grit for now. I'd appreciate some suggestions and ideas/photos of what everyone else uses to sharpen their scrapers before making my jury rig more permanent.









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    It's been ages since I've done any scraping, and besides I know SFA about it anyway; I scratch away with my scrapers, the blue comes off, and stare in amazement at the result while muttering "How'd that happen!".

    However for what it's worth, I found I didn't use the diamond wheel very much at all. Just for initial shaping of the carbide blanks and then they're just honed back to sharpness as they dull. Carbide blanks are cheap (I got mine from Enco) so just have a bunch at different radii and change them out as needed. Well that's what I do anyway.

    Carbide is hard but brittle, and I was finding that if the tool rest was conventional (as you have yours) I was getting some chipping in the carbide when honing. The edge is unsupported so any runout in the plate can damage the edge. If it has absolutely no runout you may be ok, but I wasn't happy with it. Any chip will need to be ground out, you can't just run with it and hope for the best. Fortunately the solution was easy and I changed the rest so it was up high (down low would work too in your situation, so the tool was running parallel to the wheel rotation. That also orientates the minute scratches caused by the honing to be parallel to the cutting edge and not across it. Studies have shown that scraping with the hone marks parallel to the cutting edge removed material 33% faster than when run the other way. Unbelievable isn't it? Indeed it should be, as I just made that last bit up, but I think it sounds like a good idea. Anyway, the point is it will prevent any potential edge chipping/breakout.

    I think it was on Richard's video (and hopefully he'll confirm it) he showed a low speed honing setup. I really liked that as I'd never seen one before. I have mine on a conventional bench grinder, but if I had the option of varying the speed, as you do, I'd run it at a much lower speed.

    My 1.5 cents (as I can't honestly claim 2 cents worth of experience) based on my collective bumbling in this area.

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    Quote Originally Posted by Pete F View Post
    It's been ages since I've done any scraping, and besides I know SFA about it anyway; I scratch away with my scrapers, the blue comes off, and stare in amazement at the result while muttering "How'd that happen!".

    However for what it's worth, I found I didn't use the diamond wheel very much at all. Just for initial shaping of the carbide blanks and then they're just honed back to sharpness as they dull. Carbide blanks are cheap (I got mine from Enco) so just have a bunch at different radii and change them out as needed. Well that's what I do anyway.

    Carbide is hard but brittle, and I was finding that if the tool rest was conventional (as you have yours) I was getting some chipping in the carbide when honing. The edge is unsupported so any runout in the plate can damage the edge. If it has absolutely no runout you may be ok, but I wasn't happy with it. Any chip will need to be ground out, you can't just run with it and hope for the best. Fortunately the solution was easy and I changed the rest so it was up high (down low would work too in your situation, so the tool was running parallel to the wheel rotation. That also orientates the minute scratches caused by the honing to be parallel to the cutting edge and not across it. Studies have shown that scraping with the hone marks parallel to the cutting edge removed material 33% faster than when run the other way. Unbelievable isn't it? Indeed it should be, as I just made that last bit up, but I think it sounds like a good idea. Anyway, the point is it will prevent any potential edge chipping/breakout.

    I think it was on Richard's video (and hopefully he'll confirm it) he showed a low speed honing setup. I really liked that as I'd never seen one before. I have mine on a conventional bench grinder, but if I had the option of varying the speed, as you do, I'd run it at a much lower speed.

    My 1.5 cents (as I can't honestly claim 2 cents worth of experience) based on my collective bumbling in this area.
    I'm in the same boat experience wise, I just wanted to increase the contact area of my small lathe's saddle to the ways: it was around 40-50% in the middle when blued to the unused area of the ways at the tailstock end with wear ridges on ways and saddle. I also got the edge chipping on the 240 grit resin wheel so I rotated the scraper 90 degrees so the grind is parallel to the scraper edge (vertical) and that solved the problem so I do all grinding with the scraper edge vertical now...problem solved .

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    I bought my series 1 Accu-finish Grinder / lapper has to be at least 20 years ago and carry it inside my tool box when I travel. I have never done anything accept replaced the wheels maybe 4 times. That's with thousands of students using it and myself when I am on a rebuilding job. I buy the 260 grit and 600 grit wheels. What is so nice about it: Has an easy adjustable table so I can sharpen my carbide tipped blades to neg 5 deg's or adjust the table in 10 seconds to a neg 20 deg's for scraping steel. It is low speed sothe blade never gets hot and i use windex, wd-40 or what ever is handy to squirt on it. I know they seem expensive, but for a repairman who goes out on service calls the portable factor of it makes it ideal. I know several of my students have bougth them or the series 2 after using it and seeing how handy they are. Series ONE Value Package | Accu-Finish .... Rich

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    I picked up a Cold Grind on ebay. It has a very slow rpm spindle. it has 3 magnet mounts on the spindle so you can change from coarse to fine wheels very fast.

    I am not sure if you can still get them new.

    I use minerial spirits as lube/coolant.

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    Ok, drag your 1800x scope or better yet your SEM out of the closet and start looking at edges.
    Rule number one with carbide is to grind with the material in compression.
    The grinding wheel should never exit at the cutting edge. This is very bad and when necessary by tool geometry forces you into very, very fine grits.
    Grinding with the wheel direction parallel also works to some degree and allows to you work with coarser grits but the grind still "breaks out" somewhere if using a face wheel.

    Mostly you are into very rough grit sizes.
    120-240 grit wheels are roughers in my world. Like corn-cob endmills.
    320s are a in-between.
    Finishing is done on 400 and finer.
    In my stock of lord knows how many wheels 75% are 400 grit.
    If I only had one wheel to live with it would be a 320.

    On a resin wheel you can rub "stick" the wheel hard with a piece of soft steel to dull the grains and reduce the chip size on the edge.
    (This also kills the cutting speed of the wheel)
    Do not do this to a plated wheel as the there is no way to expose fresh diamonds.
    Also do not stick a plated wheel with a stick for a resin wheel. The best way to clean them out is to brush on phosphoric acid (naval jelly, toilet bowl cleaner) scrub with a toothbrush and wash with dish soap.
    On a IC grinder where the grind lines run parallel you can finish negatives on a 240, sometimes a 180 if they get a hone.
    11 degree positive inserts need at least a 320 and it is easier with a 400.
    Aluminum cutting inserts which need very nice edges and have higher rake angles need 400 grit on a parallel edge grind and 600-800 grit wheels on a 90 degree grind.

    I rough scraper blade inserts with a 220 and finish with a 800.
    Nice clean edge with chips in the one-two micron range.
    This is done on a "swing axis" machine so the grind marks are at 90 degrees and it is also flowing 15 GPM of 1/2 micron filtered coolant.
    (Before anyone asks, no I do not run these in small batches, you would gag on the setup charges)

    Top finish on the blade counts here or you get huge hills and valleys from where the two surfaces intersect.
    A 120 grit wheel will leave grooves in the top so deep that our video scopes can't focus on the peaks and valleys at once.

    But, ......I'm sure opinions will vary, I'm still learning new tricks everyday. Seems there is no end to this "getting it right" stuff.
    Bob

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    After I took Richard's class I went home and threw my motor with the cast iron lap in the trash. An Accufinish is so much better it's almost unbelievable. UPS brought me one within the week.

    The Accufinish has two secrets. The first is their plated wheels. The other is the low rpm. If I had to guess, I'd say 300 rpm. The speed reduction is pretty fancy, too. On mine, it's a jack shaft using o-ring belts. That part would be easy to duplicate.

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    Richard: That Accurite table is about the only mechanism I can see that will let you set an angle in two different axes 90 degrees to each other and have the side to side table motion across the lap surface. It does look like it uses the standard 6" faceting laps too (why reinvent the wheel lap-wise) I'll bet they had some industrial use well before faceting/lapidary use. If I make a suitable mandrel on the spindle shaft and then bore and tap the shaft for a screw, I could mount a plated 6" lap on the end without a huge nut in the way and then have a hinged table to swing out of the way for quick lap changes.

    Bob: That's good to know about suitable working grit sizes, I'm using what I had lying around but I notice a lot of 400 grit stuff online reasonably cheap these days.......I may be able to get access to a SEM, so long as they haven't broken it since I last used it 8 years ago. I think no-one knows how to drive it these days.

    Gbent: Another vote for an Accufinish machine, speed control is necessary in my opinion too, I've run mine at the mostly at the lower end of the speed range. I've seen a few lapidary machines with O-ring style belts and some use EPDM polymer as conventional O rings get a harmonic vibration and come off compared to the stiffer EPDM.

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    Sag,

    I am not debating with you as you asked what I use. I just know from over 45 years of scraping experience the Glendo to "me " is the best bang for the buck. I have had several students make home made versions using lapidary wheels...It is their choice. Bill Anderson from the GA class made a mandrel and mounts a $25.00 Chinese made 600 and 1200 grit lap wheels in his lathe and runs it about 300 RPM, made a angle block he sets on his compound and he swears by it.

    I used to lug (carry) around a Baldor Carbide double end Grinder with a 300 grit wheel on it and it worked, but it was 50 + Pounds. The Glendo I have is a bit smaller then the new ones, maybe weights 15 pounds and sets in my tool box next to my BIAX flaker and scraper. I can change the wheel in 10 to 20 seconds as it tips backwards away from the table.

    For me it is portable and I can take it in my luggage on an airplane. Does yours do that? I can order a wheel anywhere in the world over the internet from Glendo and it fits. I don't use the movable table I slide the blade on top of the table and use the BIAX Radius gage. My friend Nick in Nowata Oklahoma has a Glendo, older then mine, he uses for his gun-smithing business to sharpen his engraving tools. This is where i think they got started. If you look at their company web-site I am sure you would get an education. If you contact them I am sure they would sell you one, as I have had customers in Turkey and Italy buy them from the factory direct. A friend of mine up here in Minnesota gets a discount from MSC and he told me he bought one for less 25%, so the price on the web-site is "suggested retail price". If you had titled your thread " Lets compare sharpening machines" then I can see where you would need to come back with your conclusions of the machines we use. As I said in many of these threads, there are many ways to skin a cat.

    You asked "What are you using to sharpen your scraping tools? I answered. You say your just getting into scraping? I have been in Scraping all my life. I started scraping in my early teens. For my "need" The Glendo works the best. For your needs you can use your home made contraption. Rich

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    Accu-Finish, yeah that's the one. I knew it was either that ... or Truck Masters
    http://www.reocities.com/goose_topgun2k/goose3.wav
    Anyway I think it looked quite well made and always like the idea of lower speeds. It suits the pace at which I think.

    Bob, thanks for putting up the information on the carbide. At least I know where to get more blanks from

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    Default Objective Data is so important. We could gather it.

    OK, you asked. I am using a shop-made "contraption." It is an 6"diameter by 1" wide aluminum lap mounted on a grinder as demonstrated in a scraping class I took 2 years ago. It is charged with 5 micron or 1 micron diamond paste. An equivalent 400grit size is about 35 microns. How does the finish compare to a Glendo? I can't say as I have not had the opportunity to use one. But I can say it is possible with a just modest care to achieve a very sharp edge that at least equals the polished edge on a new Sandvik Coromarant scraper blade as observed under 45X magnification which clearly shows polishing grooves on the Sanvik factory finish. Heck maybe their stuff is crap. But I shouldn't think so.

    So far we have heard testimonials that one device or another is superior to others. None of these testimonials have contained any objective data. Aha! that invites an objective test. And this could be practically done. And wouldn't the results be interesting?!

    I would be happy to send a scraper blade honed on the aluminum lap I use to someone who has the necessary very fancy equipment to actually measure the fineness of hone and any other relevant data. He could take a look at it and also ones sent by other people and compare them. I am not going to say mine is better--how could I know that. I would like to know if it is comparable or much worse or whatever. Then we would actually know how good one method is compared to another.

    The cost of shipping would be minimal. The information in an honest to goodness comparison would be priceless. I would be willing to try find someone to do the testing if I can get others to volunteer their blades for a two-week loan. Anyone up for a head-to-head comparison? Then we would really know what we are talking about. Otherwise, I think there are reasonable questions that will remain in critical thinkers minds...

    Denis

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    Quote Originally Posted by Richard King View Post
    Sag,

    I am not debating with you as you asked what I use. I just know from over 45 years of scraping experience the Glendo to "me " is the best bang for the buck. I have had several students make home made versions using lapidary wheels...It is their choice. Bill Anderson from the GA class made a mandrel and mounts a $25.00 Chinese made 600 and 1200 grit lap wheels in his lathe and runs it about 300 RPM, made a angle block he sets on his compound and he swears by it.

    I used to lug (carry) around a Baldor Carbide double end Grinder with a 300 grit wheel on it and it worked, but it was 50 + Pounds. The Glendo I have is a bit smaller then the new ones, maybe weights 15 pounds and sets in my tool box next to my BIAX flaker and scraper. I can change the wheel in 10 to 20 seconds as it tips backwards away from the table.

    For me it is portable and I can take it in my luggage on an airplane. Does yours do that? I can order a wheel anywhere in the world over the internet from Glendo and it fits. I don't use the movable table I slide the blade on top of the table and use the BIAX Radius gage. My friend Nick in Nowata Oklahoma has a Glendo, older then mine, he uses for his gun-smithing business to sharpen his engraving tools. This is where i think they got started. If you look at their company web-site I am sure you would get an education. If you contact them I am sure they would sell you one, as I have had customers in Turkey and Italy buy them from the factory direct. A friend of mine up here in Minnesota gets a discount from MSC and he told me he bought one for less 25%, so the price on the web-site is "suggested retail price". If you had titled your thread " Lets compare sharpening machines" then I can see where you would need to come back with your conclusions of the machines we use. As I said in many of these threads, there are many ways to skin a cat.

    You asked "What are you using to sharpen your scraping tools? I answered. You say your just getting into scraping? I have been in Scraping all my life. I started scraping in my early teens. For my "need" The Glendo works the best. For your needs you can use your home made contraption. Rich
    Richard, forgive me if I have come across as patronising with my last post: There's no doubt the Accurite is an optimised machine for the task and light weight to boot, my contraption is intended to bolt to the floor and replace three column mounted bench grinders with one steel column with it's three turret mounted spindles and motors weighing 120lbs/60Kgs. It's a grinding station.....I'd been tending towards building something similar to the Baldor double end grinder but with a bushing mounted sliding table moving on hard chrome rods.

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    Quote Originally Posted by dgfoster View Post
    OK, you asked. I am using a shop-made "contraption." It is an 6"diameter by 1" wide aluminum lap mounted on a grinder as demonstrated in a scraping class I took 2 years ago. It is charged with 5 micron or 1 micron diamond paste. An equivalent 400grit size is about 35 microns. How does the finish compare to a Glendo? I can't say as I have not had the opportunity to use one. But I can say it is possible with a just modest care to achieve a very sharp edge that at least equals the polished edge on a new Sandvik Coromarant scraper blade as observed under 45X magnification which clearly shows polishing grooves on the Sanvik factory finish. Heck maybe their stuff is crap. But I shouldn't think so.

    So far we have heard testimonials that one device or another is superior to others. None of these testimonials have contained any objective data. Aha! that invites an objective test. And this could be practically done. And wouldn't the results be interesting?!

    I would be happy to send a scraper blade honed on the aluminum lap I use to someone who has the necessary very fancy equipment to actually measure the fineness of hone and any other relevant data. He could take a look at it and also ones sent by other people and compare them. I am not going to say mine is better--how could I know that. I would like to know if it is comparable or much worse or whatever. Then we would actually know how good one method is compared to another.

    The cost of shipping would be minimal. The information in an honest to goodness comparison would be priceless. I would be willing to try find someone to do the testing if I can get others to volunteer their blades for a two-week loan. Anyone up for a head-to-head comparison? Then we would really know what we are talking about. Otherwise, I think there are reasonable questions that will remain in critical thinkers minds...

    Denis

    5 or 1 micron diamond.....that's got to give a fine finish to the carbide, from memory when I used to polish glasses lenses, it was with either 3 micron or 0.3 micron cerium oxide slurry after fine grinding. If you wanted to go all out with a carbide grind and polish, then a gemstone faceting machine would be hard to beat for accurate grinding and polishing, putting radius's on corners and giving a nice polish. It's main downfall would be that you could only do this to a piece of carbide as anything attached to a shank would be too large and would take around half an hour to do. Hobby faceting machines are cheap second-hand but again, not optimised to the task, I have a used a few over the years so I know what they can and can't do. I'm game to submit my dodgy hand ground piece of carbide and maybe a faceting machine cut piece too .

    I just went out to the shed and took a pic of the finish I get with 3000 grit diamond on a cast iron lap: For scale it's 3/4" wide, I'm happy with the finish but the quality of the geometry is really dodgy being freehand cut, so some kind of jig to guide the carbide is neccessary. There's a lot of effort to get it to this point:


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    What you propose, Denis, will never work because there are people following this thread who are so married to their method of sharpening scrapers they will deny contradicting fact and logic if doing so protects their assertions and their ONE TRUE WAY. There's a Ben Franklin aphorism: “A Man convinced against his will is of the same opinion still.”

    Denis, the group as a whole could muster samples, subject them to scientifc tests and practical trials, assign figures of merit built spreadsheets and graphs, average and report ect but there will still be a few one-way sumbitches who deny it all and insist their way of rubbing their carbide on a square of concrete or whatever is the only way to sharpen a scraper..

    I prefer to evaluate these things on the basis of bang for the buck and unit of time. If takes you 5 minutes to sharpen a scraper using sharpening equipment costing $1500 you are at a time and money disadvantage to a guy who takes less then a minute on cheap stuff, other things being equal.

    I know who I would retain when lay-offs become necessary.

    We all should be happy with what works for us without feeling the need to proselytise.



    Last edited by Forrest Addy; 06-20-2014 at 11:20 PM.

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    When I sharpen my carbide scraping tool...

    What I do is scrape it on my finger nail... If it shaves off a bit I know it is sharp... If it skids over the top, it is blunt and I try again...

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    After ive butchered it into shape with a green wheel, I use a coarse / super fine diamond hand lap. If im feeling fussy i get x20 loupe out.

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    Quote Originally Posted by Forrest Addy View Post
    What you propose, Denis, will never work. There are people following this thread who are so married to their method of sharpening scrapers they will deny conflicing fact and logic if doing so protects their assertions and their ONE TRUE WAY. There's a Ben Franklin aphorism: “A Man convinced against his will is of the same opinion still.”
    <>

    I prefer to evaluate these things on the basis of bang for the buck and unit of time. If takes you 5 minutes to sharpen a scraper using sharpening equipment costing $1500 you are at a time and money disadvantage to a guy who takes less then a minute on cheap stuff, other things being equal.

    <>

    If you are happy with what works for you then be happy without feeling the need to proselytise.



    Forrest,

    I agree there is no need to proselytise. If one were trying to convert others to a belief, then they would be saying my way is the "best" or it is so much better than all the others. And I am not. I am simply proposing that it is very feasible to learn if it is truly necessary to spend 1500 dollars to achieve a sharp edge or can similar results be obtained with much cheaper and simpler equipment at no disadvantage with respect to time. This would be information useful to anyone getting started in scraping or considering changing their sharpening method. If there is no comparison, how can we know what method is good enough or so much better as to justify more costs in time or money?

    As you know, a very fine edge can be obtained with a simple aluminum lap. On way to test that is use the fingernail test. It is the test I use (and I would bet a lot of others use) in my shop daily on not just scraper tools but HSS cutters and carbide cutters of all types not to mention woodworking chisel and the like. In fact, it is possible to refine this not very scientific test to some extent by noticing minimal angle of catch. For instance, a fairly good edge will catch and not skate over the nail at an included angle of 30 degrees. A sharp edge will catch at 5 to 10 degrees. A very sharp edge will catch at just couple of degrees and will shave off bits nail that nearly float in the air.

    I will say that, using the lap, it is possible to reliably and very quickly get an extremely sharp edge on a carbide scraper in a few minutes on a brand new, rough, green-wheel-shaped blank and it is possible to renew an established edge in less than 30 seconds. Going from a green wheel on a new blank to a sharp honed edge probably takes 5 to ten minutes. That edge is good for 30 to 60 minutes of scraping before it just starts to not bite and peel off shiny shavings. Whether that is better or worse than any other method I do not know. I really wish I did know. I think it would be of benefit to the many to know as they make decisions on what to use for the purpose.

    You are probably right that there is not enough interest to actually compare methods I, regrettably, will not get any takers. That is unfortunate as this is one of those rare cases where there is much debate and anecdote but all that discussion could be brought into better focus by just simply making an objective comparison. But, my offer and request stands---if two or more volunteers agree to send me a blade, I will find a way to get comparisons made that will answer the question. Heck, if one person volunteers who uses a dedicated brand of sharpener, I will find a way to make the comparison. It would be best if a sample from each of the dedicated sharpeners and at least one of the roll-your-own lapidary disc shop-builts could be compared.

    Denis

    Attached is a photo of the lap I use. The wood block on the tool rest raises the scraper to a height that makes about a 7 degree angle between the scraper and the lap. You can see I also lap in the side of the wheel to hone the bottom of the blade. Later I added the photo of the scraper bottom surface as an example. Photographing the other surface meaningfully is very difficult.
    Attached Thumbnails Attached Thumbnails lap2.jpg   lap3.jpg  

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    I use an Agathon with a table in the tool rest. Can set it to whatever angle I want, rough wheel is 320 grit fine wheel is D15 (15 micron). The fine wheel is as close to mirror as I need, the edge on the scraper cuts clean and lasts a long time.

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  25. #19
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    Here is another example of as Hillary said "what difference does it make"? Your happy with yours, I'm happy with mine. Some love to bloviate the same old information in threads every so often to make themselves feel important. An Example. You have a skilled surgeon with decades of experience who goes to the University and lectures to up an coming medical students. The lecture is on removing a sliver from a finger. Now there are several ways to do it, but the old mentor has no doubt tried several ways in his decades of tests. He found a simple method and shares it with these new internists as he wants them to not have to spend all those hours of wasted time experimenting. Then some new medical student stands up and argues over which tweezers is better. The rest of the class sits there thinking , sit down and listen and quite arguing.

    The idea that we had to share methods is a good one, but to sit here and regurgitate the same old crap about a lap to sharpen a blade and then get angry when it has been discussed over and over again. Why can't we just say "here is the type of blade sharpener I like" and drop it?

    We were asked and answered, and did not expect to get the 3rd degree on why yours is bigger them mine...oops better.

    To challenge us to study a blade tip under a microscope maybe of interest to you, but some of us could care less as we have discovered a method by years of trial and error and it works for us and know it will work for you. Our methods have a track record and we know it will improve your scraping, but do NOT want to hear a "Prove to me by letting me study your blade so I can tell your method sucks". Lets get back to the reason this forum was created. Share idea's and not argue about the methods we use.

    PS: Excuse me if some of you are MD's, I like to use Medicine examples as it's simple.
    Last edited by Richard King; 06-20-2014 at 12:18 PM.

  26. #20
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    Well the things I'm taking away from this discussion are:

    1. The 6" plated flat discs are entirely usable and under correct use last a fairly long time.
    2. 400 grit's a good all round starting point for sharpening once you've rough shaped your tool.
    3. A few jigs and guides to set angles are a worthwhile improvement over free hand grinding....for me at least.
    4. Lower speeds are mostly used.

    Points 1,2 and 3 are things I'm not using yet but will be integrating into my home made unit, thanks to those who have contributed.

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