Grit for shaping tools

[Jon Murphy]

I have just changed my main sharpening wheel to a CBN radiused 180 grit. I'm now looking to put the best wheel for shaping tools on the other end.

A bit of background. I'm quite familiar with grinding tools. I have a small shop and only room for my single 8" 1725 rpm grinder. I have been using Norton 80 grit on both wheels (the SG as my main wheel and an SX which I've radiused as the secondary). I need one radiused wheel as I do a lot of hollow forms with home made Ellsworth style cutters, and the new CBN with its 1 1/2" width and 1/4 radiused corners makes a perfect main wheel for all my resharpening as well as my hollowing cutters. I've put the 80 grit SG on the other end to be my reshaping wheel.

I was very surprised at how aggressive the CBN 180 can be if one applies pressure, and how gentle it can be with a soft touch. The 80 grit SG is almost redundant to it. Now to the question. If I want a "roughing" wheel for reshaping should I look to a 40 or an 80 grit 3X (I like the Norton wheels). I've never used either so have no idea of how they cut. I use the Geiger Plus 4X arm with a VariGrind as jigs so I can duplicate perfectly the shaping grind with the final sharpening (within the small limit of the wearing away of the AO wheel, but that is only the depth of the bevel).

I do a bit of reshaping, but not enough to spend the bucks on a coarser grit CBN for the other wheel. Should I try the 40 or the 60 for my secondary wheel?

A comment on the CBN 180, it is magnificent. It is not like a slow, wet Tormek (which I've used) as a "mirror" finish on the bevel, but who needs a mirror on the bevel - what we want is an edge, and that it gives. I've tried it on a new scraper that I hadn't reshaped - it takes steel quicker and cooler than the 80 grit if you apply a bit of pressure. Despite that I wouldn't have spent the bucks to make the switch except for the radiused edge for my hollow cutters - one can do very well with the good AO wheels if one keeps them even and balanced with the Geiger True-N-Dress. Much of the difference in sharpening, or touch ups, comes from variations in the wheel rather than the nominal grit.

[Thom Sturgill]

Doug Thompson recently gave a talk to a club about sharpening and they put a video on youtube. There was a link posted here a last month. In the discussion he says he uses the 'K' grade wheels. Much harder than the friable 3X wheels. They only come in 36 and 80 grit I believe and he uses the 36 grit for rough shaping and likes it bouncy, it cuts faster and cooler that way. Worth watching: http://www.youtube.com/watch?v=ZOc6giDP39A

BTW, I like the CBN wheels even though Doug does not, and disagree with his statement the the ones pushing them are the ones selling them. They push themselves, and more and more turners are converting.

[Dale Bonertz]

Jon, I would leave the SG on until you where it out. You said you don't reshape much so why not save the money.

Thom, you have to look at the perspective and use. Doug sharpens a lot of steel. I know a tool maker who won't use cbn anymore because he wore out a wheel in a year. It is not cost effective for that type of use. Most of us who just sharpen they will last much longer. It is like anything, there isn't one single lathe that will perform for everyone depending on what they turn. I stated my concerns that I don't think one of the designer lathes of today would hold up for what I turn and man did those lathe owners get the panties in a bunch. Saying things like "it works for me" or "it does everything I want it to do" doesn't make it so for everyone or everyone's application. I know you didn't say anything like that but those words tend to be what come up in these different perspective conversations.

[Thom Sturgill]

Dale, I love my CBN and would not go back. My comment on the K wheels was to give the perspective of someone who grinds a LOT of steel. From what I've read, and from my own experiences, I think CBN is the ONLY way to go for final sharpening of high vanadium steels, in fact for anything more than M4 steel due to the carbides that form. That said, a hard SG wheel will do a great job of rough grinding. I agree that what he has will work until worn out, but when it comes time to replace it, he should think about a harder wheel. Maybe someone in a club near him has one he can try?

As to designer lathes, I would love to upgrade from my Jet 1642 and may yet join the mustard group, but can't see the money for much more, but then the powermatic is the 'best' I've turned on. Since my turning tend to the small side, I would not need that much power, but do like well machined parts and top-of-the-line bearings, and after cleaning the bed many times, a stainless bed is also appealing, so a Robust is my dream machine right now.

[Reed Gray]

Dale, I am curious as to which CBN wheel that tool maker wore out. Dave Schweitzer is still using his original wheels after 3 to 4 years of grinding his tools.

As for shaping wheels, I would guess it depends on what you are trying to shape. If you want to reprofile a gouge, it isn't too much work on an 80 grit wheel. The 80 grit CBN will take off more and do it faster than an 80 grit standard wheel. If you are trying to reshape a 3/8 inch thick wide scraper, best bet is to take it to the local saw shop, draw a profile, and let them take it to one of their belt grinders, then you can go home and fine tune it.

Your grinder can make a big difference too. My old 3/4 hp no name blue grinder from Woodcraft isn't any where near as strong as my 3/4 hp Baldor grinder. Light pressure will stall the blue grinder, and I can really bear down on the Baldor and it barely slows down.

Of course, a high speed grinder will take steel off faster.

I do use my 80 grit CBN wheels every time I turn. They produce an excellent burr for my scrapers, and I use scrapers a lot. Plus, it really will balance out your grinder.

robo hippy

[Wally Dickerman]

I too love my 180 CBN grinding wheel from D-Way. As for reshaping tools, expecially heavy duty tools where a lot of steel must be removed, my blue zirconia sanding belt on my venerable 1 inch belt sander is better, faster and cooler than any wheel. Zirconia belts are near the same price as alum oxide but will outlast them by many times. They are made for metal only. For reshaping I use 60 grit.

My Delta 1 inch belt sander is an upright floor model which I purchased in 1949. It's the oldest power tool in my shop and gets a lot of use. Haven't been able to get parts for a long time so I've had to manufacture a few things myself.

[Dale Bonertz]

Thom,
I agree on the CBN I was just saying that people tend to think that everyone turns like they do therefore what they have should work for everyone else. As we know, not everyone turns the same things or way therefore different equipment may be needed. Same with grinding wheels. I have four CBN wheels (two optigrind and 2 d-way) since I have two very good grinders. They are all set up for different applications and I love the edge they put on my tools. Having said that, I love the edge, I can also say now that I have had them for over a year that the edge does not last as long when I am roughing bowl blanks. My edge on the 60 grit wheels I had before lasted about a bowl longer than the 80 grit I now use with the CBN. The 180 grit does not even come close and quite frankly worthless in my opinion for roughing. I wouldn't use anything else for finish cutting tools though.

As far as lathes go I am working on a fixed head short bed lathe with outboard bed as my dream machine, Vicmarc VL300. I currently own a Vicmarc VL300 long bed lathe if anyone is interested in buying it. For what I turn I agree with Mike Mahoney that a sliding head stock is just not stable enough to keep vibrations from happening. Now before the sliding headstock police start in on me let me be clear. I think they are good for many if not most turners but I rough turn a lot of bowls every year and they are in the 14" to 18" size range and then I core them also. By years end I would have done about 1200 to 1500 bowl blanks. I just don't believe the sliding headstock lathes are designed for this type of use. Also with the coring I do I really like the cast iron and the 1" thick bed that Vicmarc has. The sliding headstock lathes have a 1/2" thick bed which is also a concern for my type of turning. Also the bearing system that Vicmarc uses is second to none in the lathe manufacturing business. Just my opinion of what I feel I need in a machine.

Reed, I have no idea what brand they were. I just heard the story and did not question the specifics. Point is, once again, just because it works for Dave, which I think is great, it may not work for everyone else who makes tools. It is obvious that Doug feels they don't work for him either. I have not watched the entire video of Doug's sharpening so I am speaking only from the several comments that I have read on forums in relation to his remark on CBN wheels.

[Jon Murphy]

Pardon me if I don't reply to all these excellent responses, my aging mind can't remember everything.

Concur with those who say to keep the 80 SG until it wears out, but the problem is that it may never wear out as the CBN 180 can take as much steel away in the same time if used properly.

I am a fan of Doug Thompson, and have several of his tools. In the future I'll buy only his tools and shape them for myself when I know what I want. Doug kindly sent me an unsharpened bowl gouge as I wanted to do an 85 dg. tip bevel for certain shapes. BTW, it worked, but I've backed it off to 80 dgs and put a small wing on the left side of the basic "traditional" shape. Borrowed the idea from David Ellsworth's book then modified it - great for working the transition of a steep sided bowl to a flat bottom, whether open or enclosed.

As I mentioned, I have only the space for one grinder. One of these days you may see an article in the AAW Journal on my bedroom shop and the use of the midi lathe. It is accepted by the editor, but I can't get around to finishing it as I'd rather turn wood.

My budget, and my space, is limited. My lathe is a PSI Turncrafter Commander 12" VS. I've worked on others, but at 78 and in an adult condo I'm limited. If I were to hit the lottery I'd get a short bed Robust Sweet Sixteen, but the fine OneWay and VicMarc's are impractical for me as the beds are too long for my space. The Robust short bed has an extension that is self supporting and easy to mount. My PSI has a long extension I use for tool handle turning and other things - but it gives me a 40" bed I don't need (and I have to use a temp support for the end).

We of the small shop don't have to be limited - and that is the title of my articled "It ain't just pens". The vendors of midis seem to promote only "project" things like pens and bottle stoppers. My PSI 12" (which replaced my Delta mini 10", which you may date when I say it was serial #00041) has the power (1 HP) to handle a bowl of 11" (yeah, 12" swing, but we lose a bit in the shaping). I seldom turn pieces of that size as I can't get the wood - we haven't had a good storm here in NJ since Sandy and I've run out of my Sandy stock. I'm on one prosthetic leg with the other weakened by "post polio syndrome" (my case was 1945) so can't take my mini chain saw into the woods. I have to await a nice hurricane when I can get my logs at curbside.

Oh my, got off topic - but it might have been a bit of an introduction to you fine lads of Sawmill forum. I went with the CBN on David Ellsworth's advice, and as I understand it from other threads on this forum the radioused CBN was a collaberation between David and Dave Schweitzer. I need the radiused edge for my hollowing cutters, I do a lot of hollow forms with Ellsworth style tools I make myself from blanks. (Not bad, I can get an average of three cutters out of a $2 blank, depending on size. I make them in 1/4", 3/16", and 1/8" sizes, so the average varies - but the price of the square blanks is almost the same).

David has been happy with Dave's CBN for over a year (we talked about it a while back). I was quite happy with my setup, the SX 80 with the radiius for the cutters and the SG 80 for my gouges and chisels. I'll toss in kudos to Don Geiger, his True-n-Dress diamond device keeps a wheel in perfect balance (given replacing the silly plastic arbor adaptors with a proper steel adaptor). I had no need to change, except that I had to use a mini 120 wheel (3") for my 1/8" cutters as the 80 grit SX was too aggressive. I bought the CBN with trepidation, but a trust in David. My trust was not misplaced. I can touch up my small cutters, or my "big" ones on the same wheel by adjusting my pressure. I get a perfect burr for my purpose.

Now for what might sound silly. The reason that I went this way is the 1 1/2" width of my radiused CBN, It gives me a full face of about an inch for my gouges and chisels and also my rounded corners for my cutters. Good advice from you all, even if it got a bit off topic. I've covered that by taking it ever further off topic.

One can do all sorts of things with a $450 lathe in one's bedroom shop, as long as one can make a few "fixes" for the lack of alignment that is the nature of mass produced lathes. I do pens and bottle stopper project work when my lady asks for them as gifts - but my main work is hollow forms, and particularly the small and thin walled "spirit forms" that David describes. When I'm lucky enough to get a big log, or have a few bucks to spare to get some pieces of 12/4 (3") lumber from my local specialtiy wood firm, I do big bowls. But I never turn my nose up at small pieces that can be quite pretty. No reflection on the pen turners, but the pen blanks don't talk to you the way a branch does. There is both art and craft on the lathe, the art comes out when the wood says no and you have to change your original plan. That can be done with a small lathe or a large one, just on a different scale.

[Reed Gray]

Dale,
I really need to come out there to play some time. I used to turn maybe 800 bowls a year, though never kept any type of count. It is difficult for me to keep track of how long a tool edge lasts. I can put a good burr on a scraper (80 grit CBN seems to work best), and I can easily rough out a bowl or three with one. When doing my shear scraping, I generally touch up the edge before starting. Depends on how it is cutting. I have thought for some time, that along with card scrapers, some times the burr can clog up with fibers which is one reason why they seem to dull. I can take a triangle burnisher and flatten the burr on my scrapers and then turn a new burr to start cutting again. I know, some say it is impossible to burnish a burr in high speed steel, but it isn't difficult and doesn't take a lot of pressure. I haven't found the burnished burr to be better than the one from the grinder, even if I hone off the grinder burr and burnish a burr after that. Now, I have to experiment with Jimmy Clewes burr that he generates by turning the scraper up side down on a coarse wheel. He says that is better, but I am wondering how it compares to the burr from a CBN wheel. I will have to get together with him in Phoenix and see.

Gouges, for me, are used for finish cuts only. I don't have a 60 grit wheel to play with, but again, I almost always touch up the edge before starting a cut, though with some woods, I can get a couple of bowls before I need to touch up again. The thing with the platform sharpening, I can do it as fast as I can hone.

I want to play on a Vega lathe too.

I am not sure about the sliding headstock thing. I never noticed it, but haven't had a chance to compare. My Robust had a much bigger pressure plate under the headstock than my PM did. I have noticed that a bigger throw lathe will have more vibration than a shorter one. Also, the designs have changed a bit too. The Oneway and Robust have a headstock spindle that will unbolt from the headstock assembly so you can more easily take it to a machine shop to get the bearings replaced if that is necessary. This does make a bell type housing that pushed the spindle out another 1 to 2 inches away from the main frame of the headstock. Add to that how my Vicmark chuck inserts are not longer, and my bowls are now 2 inches farther away from the headstock frame. This does add some vibrations because of the longer levers. Part of the reasoning behind extending things out farther is being able to access the bottom of a reversed twice turned bowl. Since mine are finished turned, this is not a concern of mine. My old PM 3520A had the spindle coming out of the headstock base. Since things are closer to the headstock, I didn't need the tailsock. I did wear out a set of bearings in about 5 years from turning chainsawn blanks, which are more bumpy than bandsawn blanks. Part of the reason the bearings wore so quickly. With my Robust, the tilt away set up is great, and I use it on bowls over about 12 inches. Some times on smaller bowls if they are out of balance.

Every time I am starting to think that I have things figured out, some one throws some thing else in to the fire pit..... Pondering again....

robo hippy

[Dale Bonertz]

I would love to have you out any time, sounds like a lot of fun to experiment and play in the shop together. God knows I have enough wood to keep you here for well around a year or two or three. For awhile I thought I may be in your part of the world for visits because my son was considering either Washington or Oregon for college (he ended up Alabama with a full ride academic scholarship). As a side note my daughter just accepted the same scholarship to the University of Alabama last night. As Bob barker used to say "Come on down".