What angles do you grind your turning tools?

[robo hippy]

I thin, the NRS works better on spindles if you use it for a peeling cut rather than a scrape. The peeling cut is a bevel rubbing cut, and I should do a video on that some day. This is a tangent I went off on due to watching Eric Loffstrom demo a lidded box form. He used the peeling cut with the skew rather than the skewed bevel rubbing cut. The resulting peeling cut surface was not as clean as the bevel rubbing cut surface, but it was a '220' grit surface, and there were no tool marks which are standard for most of we mere mortal skew users. This, I think is the same type of cut that is shown in the Sorby clip which I now have to go find and watch again...., and clip and paste here...

robo hippy

 

[Bill Boehme]

If you're doing a peeling cut then why not use a skew? Nothing else beats it.

 

[robo hippy]

Here it is. The top bevel, I am guessing is in the 20+ degree range.... They start handle down and bevel rubbing, then raise the handle till it starts cutting, which is pretty much a peeling cut. Same on the spindles. I have used my Big Ugly tool, and other scrapers, one a 70/30 grind for the same cut. Still prefer the burnished burr. As I said above, this type of NRS on spindles gets rid of tool marks where we wiggle through the curve rather than one smooth clean sweep... Maybe some day my skill levels will approach those of Allan Batty and Richard Raffen....

View: https://www.youtube.com/watch?v=lvqwrZY2QJg


robo hippy

 

[robo hippy]

Okay, went out to the shop to try a couple of variations with a 70/30 NRS on a big leaf maple spindle. The cuts were bevel rubbing peeling cut, and non bevel rubbing cut. I used grinder burr, burnished burr, and burr totally honed off. Best cut/cleanest surface was a peeling cut with the totally honed off burr, close second was burnished burr. The non bevel rubbing cuts didn't do as well, but more of an 'okay' surface. So, that Sorby type of NRS should do better with a peeling type cut.

Dang, now I need to try it on a bowl.....

robo hippy

 

[robo hippy]

Hmm, different wood for the bowl, a particularly nasty piece of myrtle/California Bay Laurel, which does have an inter locking grain that some times wants to tear rather than cut... Best surfaces came from burnished burr shear scrape with M42 shear scraper. Didn't try gouges cause I don't use them for that. The 70/30 in peeling cut seemed to rough up the bevel rubbing gouge cut. The 30/30 NRS left a good surface if I went over it enough times, which you have to do for this type of wood, or you start with 120 or 100 grit for your sanding. Pretty much the same inside and outside of the bowl... Results didn't vary much on honed and no burr to honed and burnished burr... Since this was a more difficult wood, results would be fair to good on other more normal woods.

robo hippy

 

[robo hippy]

If you're doing a peeling cut then why not use a skew? Nothing else beats it.

Bill, most of the time, the peeling cut is used for sizing. I am using it for a finish cut. Biggest difference for me is that some thing like the 70/30 grind, that is honed, I get a really clean cut, and no tool marks. I always get tool marks with the skew, and they are difficult to sand out. I did notice that a 25/25 skew seemed to get a cleaner cut than the 30/30, but I find the 70/30 to be more comfortable because I can hold the handle more level without having to reach way out. I have a couple of 1/4 round profiles for the skew grinds, and at least one ) nose shape which is excellent for coves. Generally it leaves a 220 grit surface.

robo hippy

 

[Nick Boyd]

You shouldn't leave the wheel sitting in the water overnight or else you will wind up with the wheel frozen to the shaft because of corrosion (even if you have the stainless steel shaft with the LH threaded EZ Lock nut. But you don't always need to completely remove the water tray ... just lower it so that the wheel is out of the water ... doing this easily takes a little practice with tray empty and studying how the tray latches into position. Once you get proficient you will be able to smoothly move the tray up and down and latch it in place with the greatest of ease.

If your Tormek is an older model like mine that has the older water tray without a magnet to collect the filings, here is a solution that I posted in the Tormek forum about nine years ago:

View attachment 23546

Many Tormek users place small super magnets in the water tray to collect metal filings which helps to keep the stone clean. However cleaning the fine metal powder from the magnet is a messy and somewhat tough job because of the high strength of the magnets. I use a slightly different approach in which I use one of the larger 3/4 inch super magnets glued to the bottom of the tray near the back edge as shown in the photo. I used a product called "Goop" which does a good job of adhering to the plastic. Other adhesives like epoxy and super glue have poor adhesion to the plastic. After the Goop dried, I applied a thick coating of Goop over the magnet for two reasons.

• To make it easier to remove any metal particles from the outside
• To prevent the tray from grabbing the lower frame of the Tormek when the tray is removed to dump the water

After the second application of Goop cured, I used my belt sander to flatten it to about 3/32 inch thick (this can be seen in the inset to the picture). This step isn't necessary, but it helps the water tray to sit more level without rocking when I lower it to get the stone out of the water, but don't plan to dump the water.

BTW, John, if you have the older style water tray like mine that doesn't have the flared sides, I personally think it is better for sharpening turning tools because the flared sides on the new style water tray can sometimes interfere with sharpening certain bowl gouge grinds. I have both water trays and I very rarely use the new one.

I wonder if yours is older or newer than mine - yours though green and a supergrind 2000 has that front top angle whereas mine is square

 

[Bill Boehme]

View attachment 24415

I wonder if yours is older or newer than mine - yours though green and a supergrind 2000 has that front top angle whereas mine is square

I was looking at the picture that you posted and very surprised to see the difference. I believe that I got mine in 1999 or possibly 1998. I would guess that your Tormek is older since all of the Tormek 2000 grinders that I have seen since I bought mine as well as the T-7 have the same body style.

 

[RichColvin]

I wonder if yours is older or newer than mine - yours though green and a supergrind 2000 has that front top angle whereas mine is square

Nick,

Yours’ is older, and those didn’t come with the horizontal grinding ability. Obviously, yours has been modified to add that ability. Some upgrades are nice like the stainless steel shaft and EzyLock nut are worth adding.

Don’t worry about the age. The original Tormek were driven by a drill, and they are still being used, so you’re doing well with yours. It is still a very formidable machine.

Rich

 

[Nick Boyd]

Nick,

Yours’ is older, and those didn’t come with the horizontal grinding ability. Obviously, yours has been modified to add that ability. Some upgrades are nice like the stainless steel shaft and EzyLock nut are worth adding.

Don’t worry about the age. The original Tormek were driven by a drill, and they are still being used, so you’re doing well with yours. It is still a very formidable machine.

Rich

Thank you - I didnt do the mod and I bought it new around 1995ish. Please clarify - to start getting the wheel off - the stone, from the front label side, do I turn the nut counterclockwise - I thought I saw a conversation that to hold the wheel and tap a wrench with a hammer but clockwise..?.

 

[RichColvin]

Yep, that’s right. The EzyLock s much easier !

 

[Bill Boehme]

Thank you - I didnt do the mod and I bought it new around 1995ish. Please clarify - to start getting the wheel off - the stone, from the front label side, do I turn the nut counterclockwise - I thought I saw a conversation that to hold the wheel and tap a wrench with a hammer but clockwise..?.

I thought that all the Supergrind 2000 may have come with the horizontal base, but the ones before that didn't. However, 1995 sounds too old for the Supergrind 2000. I thought that they came out around 1998. My memory isn't too good on this matter.

The original shaft on mine wasn't stainless and I believe that the threads were RH. I do recall that tightening or removing the nut required the use of a hammer to deliver two or three sharp raps on the back end of the wrench handle. Somewhere around 2006 - 2008 I upgraded to the stainless steel shaft and EzyLock nut. I also upgraded the horizontal base to the one used on the T-7 that has two locking screws and also got the new water tray. As I mentioned earlier, I don't like the new water tray. I also have a bunch of the tool bars. The original one wasn't very good and each new version made incremental improvements.

 

[john lucas]

Well you are the expert on scraping. I seldom do it anymore except to clean up some minor lines on bowls or platters. Almost never on my mirrors and boxes and never on spindles. What I did find when I did some testing about 6 months ago was that different steels raise burr's differently. I did find on my 2 negative rake scrapers that less than 90 degrees makes a better burr. One is a Thompson scraper and one is a Sorby. I found this out because I decided to grind my flat scraper to a negative rake. Well when all you do is grind off the top angle you actually increase the included angle. My scraper was ground to something like 70 degrees. When I ground the top down it was now closer to 100 or more. It seemed to work. When I ground my Thompson round scraper to a negative rake and ground both sides to the same angle that was less than 90 it raised a really good burr. so I reground the bottom bevel of my flat scraper so I had an included angle of less than 90 and got a much better burr than before. Now that's only 2 tools so not much of scientific base.

 

[hockenbery]

I seldom do it anymore except to clean up some minor lines on bowls or platters. Almost never on my mirrors and boxes and never on spindles.

I’m like you. Some crotch figure Natural Edge bowls the inside bottoms will have twisty grain difficult to get a clean cut with the gouge and upward pointing fibers pull,out. Repeated light and lighter cuts with the gouge will likely fix it but too many repeated cuts and the bottom gets to thin. So I will use the scraper to clean up the torn grain.

I used to use a scraper for the insides of goblets but now use the hunter #4 as a cutter and scraper.

 

[Gerald Lawrence]

Well you are the expert on scraping. I seldom do it anymore except to clean up some minor lines on bowls or platters. Almost never on my mirrors and boxes and never on spindles. What I did find when I did some testing about 6 months ago was that different steels raise burr's differently. I did find on my 2 negative rake scrapers that less than 90 degrees makes a better burr. One is a Thompson scraper and one is a Sorby. I found this out because I decided to grind my flat scraper to a negative rake. Well when all you do is grind off the top angle you actually increase the included angle. My scraper was ground to something like 70 degrees. When I ground the top down it was now closer to 100 or more. It seemed to work. When I ground my Thompson round scraper to a negative rake and ground both sides to the same angle that was less than 90 it raised a really good burr. so I reground the bottom bevel of my flat scraper so I had an included angle of less than 90 and got a much better burr than before. Now that's only 2 tools so not much of scientific base.[/QUOT

Stuart Batty says on neg rake the included angle should be 70 . I reground a scraper I got at TAW to I think about 75 and that is working well.

 

[Emiliano Achaval]

Last year I hosted Guilio Marcolongo, he stayed with me a few days. During the club demo someone asked him about angles. He says he doesn't care about them, they dont matter as long as the tool works. He said people worry too much about angles... I was trying to hide my protactor as he was saying that, lol

 

[john lucas]

The only reason I know is because people ask. I used to say the same thing as Guilio but then someone told me afterwords that it was rude. So I measured so I could answer the question. Now I have conciously been making decisions on what angle mostly for ease of sharpening. It may not mathematically be the optimum angle for each tool but what I use works for me and that's what counts.

 

[hockenbery]

Bevel angles are like lathe speeds.
There are acceptable ranges for the tools and there intended use.
A degree or two doesn’t matter much.
10 degrees off can make a tool perform poorly and 20 degrees make the tool unusable for a particular application.

People new to turning want to know what the center range is.

If I get asked about speed - my answer is to explain how I dial in the speed. Then I will read the rpm - then explain this may be the only piece I turn this year at this pm.

With bevel angles I aswer with - about xx

 

[robo hippy]

The biggest difference I can see between NRS's with included angles of less than 70 or so degrees, and more than 70 or so degrees is that the more acute angles don't take a burnished burr very well. It can be done though. The burnished burrs do better on the more blunt angles. I like a 70/30 or so, more for end grain work though.

robo hippy

 

[Bill Boehme]

With lol angles I and with - about xx

I couldn't have said that better myself.

 

[RichColvin]

These types of questions are what drove me to catalogue what works for me.