what grits for belt-sander sharpening?

[johnkelsey]

Like many I've been sharpening with a two-speed 8" grinder, I've heard great things about sharpening on a jigged-up belt sander but in digging through old threads I couldn't find discussion of belt types and grits. What is best grit for on-going belt sharpening of tools that are in good shape to start? Touching up the edge then back to the lathe.

One fellow recommends blue zirconia belts over aluminum oxide, what other choices?

How do you use different grits, if you do use more than one?

And can anybody compare honing with buffing? by honing I mean a fine and small secondary bevel achieved by hand with 600 and 1200 diamond stones, I use flat Norton-brand waterstones, any burr inside a gouge wipes off with a slender round diamond waterstones. I come at this from furniture and general woodworking, that honing is second nature and takes seconds. I hone several times between grindings, including scrapers. Can anybody compare this kind of edge with a buffed edge? Which is sharper, which lasts longer?

Thanks in advance!

 

[Joe Wiener]

Maybe as a start, you might look at the Sorby web page regarding the sorby pro edge and you will see what grits and types they offer as part of their belt sanding system.

 

[Syd Sellers]

Belt sharpener

Hi,
I was just like you, spent hours honing tools while turning. I then read an article by a famous wood turner in which he stated "I like to turn not spend my time sharpening tools." I started looking at sharpening systems. My biggest issue was repeatability from sharpening to the next sharpening, I wanted the bevel to be the same each time. I choose the Pro Edge by Sorby. It uses a 2" wide belt of a number of grits from 60 to 400. If you have some old chisels that need to have their bevel angle fixed up, I use a 120 grit belt to do the job quickly then I change to 240 grit to improve the smoothness of the finish and the fineness on the edge.

Now I spend my time turning not sharpening. This same machine will handle all types of blades from plane blades, chisels, jointer blades even scissors. It also will do all the various grinds we turners like to use like fingernail and the Irish grind. You have to purchase or make your jigs to perform these grinds but the machine will do them all.

Hope this helps.

 

[MichaelMouse]

I sharpen my brush hog blades on 40 grit, the push mower on 80, and my lathe tools on 100. Seems a suitable scratch pattern for the tasks each must perform. The one thing I don't do is press hard into the belt, because it heats up the tool. Finer the grit the faster a bit of carelessness will burn. You can find your own compromise between durability and price based on grit composition, adhesive, shape, and whether of not you can get them at the local Borg.

Secondary bevels are for striking tools. Or plane irons, where the edge meets the wood straight on. Not as fragile as a more acute sharpness angle. That said, and the obvious - harder alloys are more brittle - reiterated, we don't use many tools ground to 25 degrees in turning, so it's probably not a problem we need to address, even when we're taking more of a scrape than a slice.

Honing of wear-resistant alloys is tough on a stone, so the diamond with steel is what lasts best. Necessary? Depends on the turner with whom you speak. If s/he slices, the wood runs down the edge, so it's a bit like a saw. Some say they like the "bite" they get entering a cut with a coarser edge. At the other end are the "shave with my skew" set. I'm a slicer, not a stabber, so my 100 grit grinder then to work routine does just fine. I hone my high carbon tools occasionally because they'll bend a bit rather than break on the edge, and honing renews them.

Buffing - stropping with compound to a shining bevel and smooth edge - is for human-power tools. I hone and strop a lot with carving tools, but they're used largely straight ahead and very few are make of wear-resistant hard alloy. With just a bit of skew into the cut they produce a shiny depression, not squashed grain. But the wood's stationary and I move the tool.

Been here? http://www.woodturnersamerica.com/i...-little-time&catid=99:jerry-wright&Itemid=149

 

[AlanZ]

I typically use either a 240 or 120 grit belt on my 2"x72" belt grinder.

 

[ihmserv]

i have a 4 x 36 system similar to Jon Siegels.

I use the 150 mostly, and 220 for skews.

IAN

 

[Bill Boehme]

I thought that grits only came in one size.

I like my grits plain -- no cheese.

 

[Gretch Flo]

Gretch

I thought that grits only came in one size.

I like my grits plain -- no cheese.

Bill-you must have alot of Taste buds. I can't stand their blandness without lots of butter and sa/pepper the kitchen sink. But then I have only had them a few times when I ate them out of courtesy, Gretch

 

[john lucas]

Gretch That how I feel about Couscous. I'll take grits any day. I guess I'm just a southern redneck.

 

[Bill Boehme]

Grits are actually just a carrier for the stuff that it is used to "dress it up". I would put it ahead of beets which are nothing more than plate decoration and should not be eaten except under the most dire of situations. I did eat some when I was in the Army. Garbanzos are OK in the right (or wrong) company. I am unfamiliar with couscous -- is it something like kudzu?

 

[hockenbery]

Don't forget to true your grit before using

 

[Gretch Flo]

couscous/grite

Grits are actually just a carrier for the stuff that it is used to "dress it up". I would put it ahead of beets which are nothing more than plate decoration and should not be eaten except under the most dire of situations. I did eat some when I was in the Army. Garbanzos are OK in the right (or wrong) company. I am unfamiliar with couscous -- is it something like kudzu?

Couscous ranks right up there with grits, John. On the other hand Bill, beets from my garden are very sweet, hardly needing any butter. IT does make your pee red, tho as we found out when the babysitter said there was blood in the urine of my 2 yr old daughter. Now my husband is/was a clinical pathologist but you know who took the urine into the vet clinic to run it HERSELF!!!!Gretch

 

[Gretch Flo]

"true grit"

Don't forget to true your grit before using

John Wayne will forgive you for that one Al, Gretch

 

[odie]

From what I'm seeing here, it looks like those who are using belt abrasives for sharpening are not going above 240 grit for the job.

I can remember using a 4x36 belt sander to sharpen back in the early 80's when I was turning on a Shopsmith. I don't believe I ever went above 240 grit then, but I may have.....just don't remember. Anyway, I didn't use the belt for long before I got some good grinding wheels for a 6" 3450rpm grinder and honed with slip stones.

These days, I'm using an 8" grinder with 80gt SG wheels and honing with 600grit diamond hones.

True, it's been a long time since I last used a belt......but, what I don't understand is how a 240 grit belt can possibly sharpen a lathe tool to the degree that the 600 grit diamond hone can.......or, am I understanding the belt sanding process as it's currently being used by lathe turners.....?

Are you using the belt, and then honing by hand?

ooc

 

[AlanZ]

Odie,

Yes, I use the belt then hone by hand.

Of course, if I wanted to, I could switch belts... to a very fine grit... I have some 1,000 grit trizact belts that are amazing.

 

[john lucas]

Odie when I took a 1 day class with Frank Sudol he used a worn 400 grit 1" belt on a strip sander to sharpen. He claimed it was about like a 600 grit. I never could sharpen on that thing and by the end of the day couldn't wait to get home and go back to my old sharpening routine. I think since then I've improved my touch a lot because I keep a 600 grit belt on my 1" strip sander and will often use it when I'm making tools carving tools from scratch to get rid of that last little bit of groove marks left from courser shaping and sharpening.

 

[odie]

Odie,

Yes, I use the belt then hone by hand.

Of course, if I wanted to, I could switch belts... to a very fine grit... I have some 1,000 grit trizact belts that are amazing.

Odie when I took a 1 day class with Frank Sudol he used a worn 400 grit 1" belt on a strip sander to sharpen. He claimed it was about like a 600 grit. I never could sharpen on that thing and by the end of the day couldn't wait to get home and go back to my old sharpening routine. I think since then I've improved my touch a lot because I keep a 600 grit belt on my 1" strip sander and will often use it when I'm making tools carving tools from scratch to get rid of that last little bit of groove marks left from courser shaping and sharpening.

I started to post yesterday, and had gone as far as typing it out.....but, after having a few "revelations, and memory stimulations", I decided to think this through a little more........

John, I think I can understand your frustration with the "strip sander" and doing this on a flat platen. A flat platen is also what the Sorby "pro edge" system has......and, I think this is the source of the problem you are having, as well as when I was sharpening on a belt in the past......unless you also hone to the final edge with the belt, as Alan Z does.

With a perfectly flat bevel, you cannot hone by hand without introducing a secondary bevel. No matter how it's done, you will be producing a secondary bevel, unless you are hand honing the entire surface of the bevel.

With a perfectly flat bevel (as opposed to a hollow grind produced on a grinding wheel), once a secondary bevel is produced, you cannot ride that bevel at all, because the initial ground bevel (at the heel) will prevent the cutting edge from presenting itself fully to the wood.........the honed edge will always be prevented from dipping below the surface of the wood while the bevel is in contact. Thus, this prevents your keenly honed edge from cutting as well as it could.

The hollow ground bevel, produced by a grinding wheel, allows for several successive honings (by hand) to be done before the secondary bevel is large enough to prevent the keen edge from producing a clean cut......because the hollow ground bevel allows for the edge to actually dip below the surface of the wood right from the start, and the flat bevel produced by the belt only allows the honed edge to meet the wood but not undercut the surface, when riding the bevel.

I believe all this flat bevel vs hollow ground bevel was explained in a video I once saw......but, the memory of it is so vague that I can't remember what video it was that I saw, or who made it. When it is explained this way, and in context with after having a little experience with the lathe.....it makes a whole lot of sense to me now, whereas when this concept was first embedded into my memory, it probably didn't mean as much to me back then.

ooc

 

[Bill Boehme]

From a real world practical point of view:

• it is not possible to produce a flat bevel from a belt running on a flat platen -- the bevel will always be slightly convex.
• except for really long bevels such as found on a thick skew, the amount of hollow in the bevel is so slight that it only has meaning if using a diamond hone as the final step of sharpening.
• the meaningful difference between the two above methods of sharpening is indistinguishable for most turning tools like bowl gouges or scrapers.

Another observation is that you can get a smooth continuous bevel if using a jig to hold the tool, but i have never seen anybody who is able to do this freehand -- including the most well known proponents of freehand sharpening. I also observed that whether the bevel was perfectly smooth or had more facets than the Hope diamond (but with a truly sharp edge without glint), the difference in actual cutting results were not readily apparent.

My conclusion is that it is OK to be pedantic about sharpening as long as it is not obsessive.

 

[Gretch Flo]

600 diamond hone grit vs 600 grit sandpaper

Are they the same?? Was trying to look back on bookmarks about sandpaper (thought it was in Vince's website(http://vinceswoodnwonders.com) which is no longer there. Is he still in business???) and comparing PS to ? other letters-(which I don't buy) . They do not equate so when progressing thru the grits you can't mix them. Gretch

 

[Bill Boehme]

Are they the same?? Was trying to look back on bookmarks about sandpaper (thought it was in Vince's website(http://vinceswoodnwonders.com) which is no longer there. Is he still in business???) and comparing PS to ? other letters-(which I don't buy) . They do not equate so when progressing thru the grits you can't mix them. Gretch

I think that there is a fine line between the two.

I am not up to snuff on buying sandpaper online -- I generally stock up for the year at SWAT. Steve Worcester is always there and also Bruce Hoover (the Sanding Glove) who has really gone "big time" in the past few years. I believe that Vince used to be at SWAT, but I do not remember seeing him there last year.

p.s. -- I just checked and he is still there at http://vinceswoodnwonders.com/

Maybe the Internet connection was a bit slow when you checked.