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Thread: More sharpening (some specific questions)

  1. #16
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    Quote Originally Posted by john brenton View Post
    I started out trying to keep things as simple and neander as possible, not just for some weird innate desire, but also because of money issues...and the time I've spent doing everything by hand is invaluable.
    This is basically the stage I'm at - I've done enough to know that I want to stick with it, and have a list of projects to last me quite a long time, so I'm starting to gradually add more tools and learn new skills. This site has been an amazing resource, and the discussions on here are definitely helping to prioritize things for me. My goal is to eventually be able to build classical guitars, which generally don't seem to benefit much from powered equipment.

  2. #17
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    If you buy already thicknessed wood,you can hand plane down the 1/4" thick tops by hand. They can be had made to 1/10" thick,but I like to determine thickness myself. That and wood selection are major issues in tonality.

    I found that I used my 14" bandsaw and drill press the most back in the 1960's. I'd have loved to have had the Delta 18-36" open side thickness sander I have now.

  3. #18
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    Not sure if you were the poster I sent this link to the other day, but in case you missed it:

    http://mysite.ncnetwork.net/resr7g3w//

    If this guy ever takes his site down I'm going to be pissed that I didn't print out the pages and keep a book. It's a wonderful site.

    Quote Originally Posted by Shaun Mahood View Post
    This is basically the stage I'm at - I've done enough to know that I want to stick with it, and have a list of projects to last me quite a long time, so I'm starting to gradually add more tools and learn new skills. This site has been an amazing resource, and the discussions on here are definitely helping to prioritize things for me. My goal is to eventually be able to build classical guitars, which generally don't seem to benefit much from powered equipment.

  4. #19
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    Quote Originally Posted by john brenton View Post
    Not sure if you were the poster I sent this link to the other day, but in case you missed it:

    http://mysite.ncnetwork.net/resr7g3w//

    If this guy ever takes his site down I'm going to be pissed that I didn't print out the pages and keep a book. It's a wonderful site.
    John, wasn't me but I have looked at that site a few times. The best resource I've found (by far) is the luthier's forum on Delcamp - pretty sure that's how I ended up finding this forum, and everything else useful. If you've never been there be prepared to waste a lot of time reading through their posts.

  5. #20
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    I am not one of those who enjoy turning a crank with 1 hand and holding a blade with the other. When I was young,every old light house we lived on had those hand cranked grinders. I hated to use them.Electric grinders can be had so cheap these days,for an import,I just can't see the point of getting a hand cranked grinder that will probably cost just as much,and need cleaning up,restoration,etc..

    You don't have to spend $300.00 on a Baldor to have a serviceable grinder. I have had an import,among others,since the 70's,and it still works fine. My other 2 bench grinders are old Sears flat front grinders from the 1960's. I actually like them well enough that I haven't needed to upgrade them. Their flat front motors allow grinding drawknives without hitting the motor. They also have double jointed tool rests. you can turn them completely straight out,and catch your chisels or gouges in the crook of their tangs. This allows you to place them at exactly the same angle on the wheels every time,so you get a neat,un faceted bevel. Or,you can put a little C clamp on a blade to catch on the tool rests to get accurate repeat angles on plane irons.

    Beyond them,anything else can be ground on my Wilton square wheel belt grinder. They are not pretty,but they are the most versatile grinder out there for making knives from scratch. I enjoy the precision that can be achieved freehand in grinding things like Bowie knives on them. Since the belt grinder cuts so much faster and cooler,it is really my most used grinder. I got one of those Jet wet wheel Tormach(sp?) grinders cheap,new in the box for $100.00 IIRC,but the stupid thing keeps breaking down. the little press on contacts in the circuit board are made from beer can gauge aluminum,LITERALLY,and they crack. Next time I get around to removing the circuit board,I'm going to solder every one of them,not just the broken one.

    Those familiar with my work know that I do much work by hand that cannot be done by machine. No offense to those who want to get crank grinders,but there is just nothing "noble",or whatever,that I can see about using a crank grinder. It's not the same as hand carving or other personal skill driven work. It is just plain work. We had to put up with those forever in Williamsburg,the large sandstone wheel types. It took forever to sharpen a plain,laminated old style plane iron on one of them. The only hard steel part on those was the thin layer of hardened steel,and it still took forever.

    This isn't meant to be a rant,though it seems to read like one. I guess I just like to save my energy for useful work before I run out of steam(which is getting easier to run out of.)
    Last edited by george wilson; 05-12-2011 at 4:45 PM.

  6. #21
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    George, thanks for all your help and input with this. It's sometimes tough to tell where advice is coming from - it's great to get advice that is time tested and I really appreciate it.

  7. #22
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    If I am only making a theory,I say so. What I say is usually based upon actual experiences. I'll be the first to admit that I am as bad as anyone to use out dated methods and do everything the hard way. Being in a museum situation from 1970 to 1986,I was forced to use old methods. Most of the time,I didn't mind,as I used them anyway. The 2 things about using 18th.C. tools I liked least were methods of drilling holes(except I like using a pump drill),and grinding. Had no problem with wooden planes and still use them. No problem with hide glue. It is the best thing in many cases,and is time proven,and reversible. No problem with chisels and gouges. They haven't changed that much. Nor has sawing. A lot of hand tool work hasn't changed that much.

  8. #23
    Quote Originally Posted by george wilson View Post
    Many thousands of woodworkers use diamond stones on steel. I have since the 70's. What's the problem? An Arkansas stone is much softer than a ceramic stone. I have easily ground damaged Arkansas slip stones to special shapes on my belt grinder with ceramic belts. You can't cut a ceramic stone like that,though. It won't need flattening,ever. India stones are good stones,but pretty out dated. I used them many years ago.

    If you mean don't use a coarse diamond stone on your steel,I use a 325 and a 600 grit diamond stone on steel.
    George,

    I've written about this a number of times. This is from one of my more recent posts about it:

    "I once had a number of plane irons to do that needed accurate clearance angles ground to their sides. I decided to use the diamond grinder and ordered in a new set of grinding wheels for it. In a very few minutes and with little progress I had worn out a pretty expensive grinding wheel. I called the manufacturer and spoke to their tech rep.

    He explained that diamond grinding wheels shouldn't be used to grind ferrous metals. They're designed for things that generate a granular grinding swarf like carbide, stone or glass. The diamonds are mounted in a nickel matrix that's intended to slowly wear away as the layered structure of the diamonds fail. Each diamond is a series of brittle layers and, as their cutting edges wear, they fracture and spall away exposing another layer with fresh edges. Steel and other ferrous metals have a stringy shaving-like swarf that quickly wears the nickel, undermining and releasing the diamonds. I believe some of the diamond stones available use a resin matrix but I doubt these are more resistant to the metal shavings in the swarf of ferrous metals.


    This is why all the texts on machine shop practice say to grind away the steel backing on carbide tipped tool bits with a regular grinder before grinding the carbide with a diamond grinder. It also explains why I wore out the first extra coarse diamond stone I bought so quickly. However, the extra coarse stones we use for dressing oil stones seem to last and last."


    A link to the osculating diamond grinder we use:
    http://tinyurl.com/26pgkud
    Wheels for this grinder run about $160 each.

  9. #24
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    I have written also: grinders with diamond wheels for use on steel run at about 200 RPM. I had one at work(which was over $2000.00),and was lucky to find a used one for home very cheap,and it is a floor model. Wheels are about $275.00,so you can bet I'm not abusing it!!

    The rep did not steer you in the right direction. What he said was true for a fast grinder only.

    I understood you were speaking of the diamond bench stones,though. There is no harm in using them on steel. That is what they are primarily made for. Google diamond bench stones for steel. What kills diamond on wheels is speed,where the diamond builds up enough friction that the carbon migrates into the steel. They are,as you said,for carbide.

    I also have a high speed carbide grinder that runs 3450 RPM,and is ONLY for carbide in my shop.

    It is easy to Google that it is true that the carbon in diamonds goes into steel if used at high speeds.. I showed that to Pam last month. There are diamond wheel manufacturer's statements you can read on the internet.

    I have had my diamond stones at home for several years,at least 12,maybe longer. At the shop,we had one of the very early diamond bench stones,which,unlike today's stones,was mounted on a solid block of acrylic,instead of on a cheaper cast plastic base we were given the stone in the 1970's by a donor. That's how old it is,and we were still using it when I retired,on steel tools. These are,of course,the common nickel matrix stones now also available with a steel plate.

    Please google it for yourself if in doubt. You are denying yourself a quick and easier way to start an edge,or get rid of small nicks if you don't use a diamond bench stone.

    Google accu-finish. It is a low speed horizontal/vertical diamond grinder. It mentions HSS (machinists don't usually use plain carbon steel),as well as ceramics and carbide to be sharpened on it. Mine is a Sunnen.

    I know you have had disagreements with Ron about carbon migration. It is not necessary to debate this subject,as anyone who cares to can google around and see that diamond carbon does migrate into steel(at high speed),and slow speed grinders with diamond wheels can grind steel. Your rep did not supply you with complete enough info about your diamond options.
    Last edited by george wilson; 05-12-2011 at 9:04 PM.

  10. #25
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    Larry, Would you please expand on this;

    Quote Originally Posted by Larry Williams View Post
    All the oil stones require is appropriate dressing before each use to stay flat and fast cutting.
    Thanks

  11. #26
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    I have not found it necessary to flatten or dress an India stone before each use. Maybe after months of use.They are aluminum oxide,and a pretty dense,hard stone. I used them all the time in the 60's,and still have some in my bench . You can clean them if they get full of crud,but that can be done with a stiff brush and powdered cleanser and water without wearing them out by frequent flattening.
    Last edited by george wilson; 05-12-2011 at 8:56 PM.

  12. #27
    Chris,
    Oil stones, both novaculite (Arkansas) and aluminum oxide (India), dull with use. In that regard they're like grinding wheels. Light dressing with a diamond stone refreshes the cutting surface, just like dressing a grinding wheel. Careful application of the diamond stone when dressing oil stones will maintain a flat face on the stone. It doesn't take a lot of dressing and leave the slurry on the stone for use. Try it, you'll be amazed at how fast India and Arkansas stones cut.

  13. #28
    Quote Originally Posted by george wilson View Post

    The rep did not steer you in the right direction. What he said was true for a fast grinder only.

    ... What kills diamond on wheels is speed,where the diamond builds up enough friction that the carbon migrates into the steel....
    George,
    The grinder we have is very low speed, maybe even less than 200 rpm.

    Diamonds migrating into steel is a wives' tale. Diamonds, like coal, are pure carbon and they'll burn just like coal. Yes carbon does migrate through steel but only above critical temperature which is is in the 1400+ F range. Diamonds auto ignite at 700 C or 1295 F, long before steel reaches critical temperature. Those who think they're observing diamonds migrating into steel don't seem to realize the diamonds burned up and turned to CO and CO2. The diamonds go away but they go into the air, not the steel.
    Last edited by Larry Williams; 05-12-2011 at 10:08 PM. Reason: clairity

  14. #29
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    True,I would dress an India stone to sharpen it,but not to flatten it. Scrubbing out the crud helps,too.

    There are manufacturers of diamond wheels that specifically state that the carbon migrates into steel. I urge you to do some more research if you think this is a wive's tale. When I was discussing this with Pam,I googled diamond dissolving into hss. I got an article put out by SP3 Diamond Tool Makers. It specifically stated that microscopic examination proved that diamond carbon does migrate into steel. Now,of course I can't find that article. You have my word that this is exactly what was said,though.

    The Accufinish grinder also mentions that it is for HSS as well as carbide,ceramics,etc.. That CAN be found.

    This is all I can tell you.The subject has also been discussed at great length on the Practical Machinist's Forum,where there is an agreement that diamond carbon does go into steel. I will continue to get the ease and benefits of using diamonds on steel. You will just keep over working yourself doing it the hard way,and that is fine,too. To each his own. I haven't worn out my diamond bench stones yet after many years.

    Technique might have some bearing on wearing out diamonds. You must not bear down too hard on them.
    Last edited by george wilson; 05-12-2011 at 10:42 PM.

  15. #30
    Some how I messed up the link to the grinder. Here's the right one:
    http://tinyurl.com/26pgkud

    If diamonds migrate into steel, it would absolutely have to be on the atomic level. The one distinct feature of a diamond is its crystalline structure. Remove a carbon atom from a diamond and it's just a carbon atom. Are you saying, George, that someone can tell if a carbon atom came from a diamond? How do they do that? It's no longer crystalline, as a single atom it can't be.

    HSS grinds much like carbide. Surely you've noticed the difference between the spark patterns when grinding HSS vs. high carbon steel. I'd be comfortable grinding HSS with our diamond grinder but I know what happens when one grinds high carbon steel with it. Want to buy an expensive diamond grinding wheel with few diamonds and little nickel left? I have one I can spare.

    Trust simple physics, George. Diamonds burn up before steel reaches critical temperature. Those that think diamonds migrate into steel inhale a lot more diamond than migrates into the steel.
    Last edited by Larry Williams; 05-12-2011 at 11:44 PM.

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