gouge reshaping thoughts

[Ken S]

One of the tests I had been wanting to perform with the T4 was reshaping a bowl gouge. Related to this, I also wanted to see how the Norton 3X grinding wheel performs in this task with the Tormek.

Before describing the process, I will note the time involved. I was able to reshape a half inch Glenn Lucas bowl gouge from fingernail shape to a flat grind (position 0 on the gouge jig) in around seven minutes. The return trip back to fingernail grind took around the same time. For an operation rarely performed, this seems entirely satisfactory to me.

I used a Norton 3X 46 grit eight inch grinding wheel in the T4 for this. In this case, as the 3X wheel is only available in six and eight inch diameters, the 120 RPM speed of the T4 motor produced 20% more Surface Feet per Minute than the T7's 100 RPM motor speed (based on 60Hz North American power). I do not consider the SFM difference significant.

The 3X wheels are far from ideal with the Tormek. Norton uses a series of round plastic bushings to compensate for smaller diameter grinding shafts. The smallest diameter with the eight inch diameter is 5/8". I was able to adapt a short piece of Schedule 80 water plastic pipe with 5/8" outside diameter and 7/16 inside diameter. drilling out the ID of the plastic pipe to 31/64" made an acceptable spacer for the Tormek's 12mm shaft.

One area where the Tormek grinding wheels are superior to most competitors' products is the permanently attached and accurately bored center holes. In comparison, the slide in series of diameter spacer bushings seem Mickey Mouse (English idiom for second rate).

The 3X thickness is only one inch (25mm). the SG-200 has a thickness of 40mm; the SG-250 is 50 mm thick. I find the thicker wheels luxurious. No 250 mm diameter size is available. Unlike the SG Tormek wheels, only one grit size is available for each wheel. (These wheels are available in 46 and 80 grits.)

Due to the coarseness of the grits, these wheels can make short work of grinding a stone grader. (not surprising, the stone grader was never design to work with such coarse wheels.)

What the 3X wheels do well is cut fast, much faster than the SG wheels. The finish is not as smooth as with the SG wheels, however, it is not as rough as one might expect.

I have used a 46 grit 3X wheel on my dry grinder for several years with good success. The coarse grit cuts very quickly and surprisingly cool. I have recommended the 3X before on the forum as an ideal dry grinder stone. For me, the problem is the dry grinder is still the dry grinder. I do not like the heat, the dust or the sparks.

For occasional use, I believe using a 3X wheel is a viable alternative to using a dry grinder with a BGM-100. With either choice, we are getting further from the Tormek's strongest area. I firmly believe Jeff Farris' wisdom in the Tormek Turning DVD: having a separate gouge is preferable to reshaping back and forth and approach reshaping gradually. With either method, the finish cuts need to be made with the Tormek SG wheels and should be polished with the leather honing wheel.

As I stated earlier, I am not an active turner. These are just tests rather than part of my day to day routine. I share this information only to offer options. I welcome comments.

Ken

[Ken S]

I have been working more with the bowl gouge and reshaping. I was requested to bring the gouge to the show in Hartville as 2-A 65. That means using the #2 swing setting on the gouge jig; hole "A" and a projection distance of 65mm (the middle slot) on the TTS-100. To do that, I needed to reshape the gouge from "4" to "2", not a major change. Instead of using the 46 grit wheel on the T4 in the vertical position, I used the 80 grit wheel the T7 in the usual horizontal position.This configuration is less aggressive in SFM; grit: and grinding direction.

I learned that the spacer washers used to adapt the more narrow wheel to the T7 need to be positioned between the Tormek and the wheel. For the EZYlock to work properly, the EZYlock nut needs to be in direct contact with the grinding wheel. Once I figured this out, it was no problem.

Changing from a 4 to a 2 took only four minutes (rough grind only). The surface from the 80 grit wheel was probably as smooth as many turners use. At that point, I switched to the SG-250 graded first coarse and then fine. Finally I switched to the leather honing wheel with Tormek honing compound. I would guesstimate finishing up with the Tormek wheel added another five to ten minutes to the initial four. Compared with some of the horror stories I have read on the forum, my time seemed quite acceptable.

I had created a two millimeter groove in the 46 grit wheel. The stone grader was no help. No shame, it is not designed for such a coarse wheel. In fact, the wheel dressed the stone grader. I was reluctant to try the TT-20, as a replacement diamond is expensive.

I decided to try an old grinding wheel dressing stone I have had for almost forty years. It resembles a cinderblock 1"x1"x6" (25x25x150mm). I moved the universal support very close to the grinding wheel in the horizontal position. I placed a single thickness of vinyl electrician's tape on the bottom to protect the universal support finish. Being beneath the USB, the dressing stick was drawn toward the USB and quite controllable. I was able to flatten the grinding wheel. Due to the depth to be removed, the operation required perhaps twenty minutes. I believe a "Norbide" stick would work better. I happen to have one, and will try using it next time. Also, I will true the stone well before it gets that bad in the future. I hesitated this time because I was not sure what to do.

The 3x wheels work with either grit on either machine and in either direction. The T has more swing room than the T4. I believe I favor the horizontal position for possibly a little more control. The 80 grit wheel seems aggressive enough for M2 high speed steel.

Based on these results, for future work, I would use the 3X wheels instead of using a dry grinder with Tormek jigs. I like the cool, dust free environment. One 3X wheel is ll that is necessary. It costs just slightly less than the BGM-100, and there is no need to purchase a dry grinder, plus decent wheels. I do not believe my 3X wheels will see anywhere near the use that my workhorse SG wheels receive. It is nice to have some reserve firepower.

Ken

[Rob]

Interesting tests there Ken.  So the Norton wheels seem a viable alternative to the perennial problem of fast steel removal (shaping).  I guess on a practical note though you wouldn't want the hassle of going to the trouble of changing a wheel every time you wanted to shape a tool.  Though one might argue that because that's not done that often it is feasible to do a deliberate setup for shaping.  On the other hand a simple dry grinder costs about £50 here and that can be permanently setup.  What do the Norton wheels cost?

The Norton wheels do perform better than a regular dry grinder do they not? I mean in terms of overheating?

[Ken S]

Good questions, Rob.

Changing wheels with the EZYlock shaft really is no hassle. In fact, from start to finish, you would be well into turning with the Norton wheel, even with a wheel change, long before you would complete reshaping with a Tormek wheel.

How often? You are one of the most active turners on the forum, Rob. How often do you reshape your turning tools? Would two or three sessions cover most users?

Does the "simple £50 grinder" come equipped with wheels equivalent to the Norton 3X wheels? Or with a Tormek BGM-100? Or with eight inch (two hundred millimeters) diameter wheels?

The Norton 3x wheels cost $40 to $60 each, depending on diameter. Either the 46 or 80 grit suffices; we don't need both. Costwise, for someone who already has either size Tormek, adding the Norton wheel for the odd reshaping occasion is less expensive than the dry grinder route. And, used wet with a Tormek, the process is quite cool.

For those who already have a dry grinder, the 3X wheels work very well dry. I used a six inch 46 grit 3X wheel on my dry grinder with good results long before venturing into using them with the Tormek.

Would a 3X wheel work dry with a Tormek? I have not tried. Using the Tormek with a 3X wheel give speed with a cool water bath environment with no dust or sparks. For me, that is he best of both worlds.

Is a 3X wheel ideal with the Tormek? Definitely not. The width is only 25mm (1inch). Ideally it should be as wide as a Tormek wheel. Adapting the bore to 12mm requires a little modification. For the price, the 3X wheels work very well and work with either a T4 of T7.

Ken

[Elden]

For those who already have a dry grinder, the 3X wheels work very well dry. I used a six inch 46 grit 3X wheel on my dry grinder with good results long before venturing into using them with the Tormek.

   Out of curiosity, has anyone tried applying coolant to BGM-100 dry grinding process? It has the potential of being messy, but what if a very fine mist or fog of a small amount is used? I have wondered about it during past discussions of this type of topic. We used such to cool hogs in the hot summertime on the farm.

[Ken S]

Elden,

I remember an article in a very early issue of Fine Woodworking (back when it was in black and white). I believe the man's name way Ryerdal. He used a mister with his grinder to sharpen turning tools (freehand, no jigs). The idea has always fascinated me, however, I believe using the Tormek is more practical. With the 3X wheels (especially the 46 grit wheel), the Tormek cuts fast and cool.

Ken

[stevebot]

I want to mention wax as a coolant for grinding operations.  I say mention instead of recommend because of some reservations I have. If you use wax on a wheel and do not like it, I do not know how you would remove it. Perhaps melt it out in the oven and follow with a solvent?

Wax has long been used as a coolant/lubricant on paper knife sharpening wheels.  These have a sandpaper-like coating on the wheel, and it can be removed and replaced fairly easily.  In addition to lubing and cooling, wax modifies the grinding by filling the valleys between the grains of abrasive, making it cut like a finer grit.

If you want to experiment with wax modified grinding, I suggest you start with your belt sander. A belt is only a few $$ and can be easily replaced.

[Rob]

Interesting idea, not come across that one before.  Thanks Steve.

[Elden]

http://www.arboristsite.com/community/threads/kool-grind.150721/

   I have seen Kool Grind advertised along with the chainsaw chain grinding accessories by Foley Belsaw. According to the above discussion, as Steve alluded, the jury is still out.

http://granberg.com/product/kool-grind

[Ken S]

The big flap about reshaping fascinates me. I am not an active turner, however, I have had some good instruction in turning. I think Jeff Farris made two very wise comments about reshaping turning tools:
1) Consider purchasing a tool in the configuration you want. That way, if you change your mind, you still have a tool in the original configuration.
2) Make changes in steps.

I had the opportunity to reshape a bowl gouge several times last fall. Reshaping with the SG-250 was noticeably slower than with a 3X wheel. I did not try using the SB-250, something I regret. Spending approximately $60 USD for a 3X wheel is definitely less expensive than outfitting a dry grinder or belt grinder.

Unless you need a lot of reshaping with turning tools, I believe the most cost effective methods are:
1) Trudging along with an SG wheel, or an SB, if you already have one.
2) Buy the tools you want pre shaped. If you are buying top of the line tools, like Thompsons, talk with Doug Thompsom about having the tools reshaped. Doug is very client friendly.

Using a dry grinder or belt grinder puts you back in the dusty, sparky, hot environment. I have a belt grinder which I like. It does a few tricks not easily done with the Tormek, however, each time I use it I am reminded how pleasant the cool, dustless and sparkles the Tormek is to use.

Ken

[Rob]

Turners are a funny bunch Ken.  There is a fair degree of variation in the personal taste of the kinds of grinds they want.  Also, quite often folk over here will buy 2nd hand tool steel with no handles from shows for which they turn their own handles.  That's a significantly cheaper way to access good quality steel but of course it means you don't have anything like a factory grind in many cases.  That's where reshaping comes into its own and also as stated above where the turners want to "play" with different profiles to determine their effect.

I've seen all sorts in my club...even a pen knife was ground in a way that caused it to vibrate when pressed into the wood to get a deliberate textured effect (this was to save the owner spending best part of £100 on manufacturers spiralling tools).  So what I'm saying is I witness first hand the thirst from turners at club meets to do experimental grinds on gouges skews and box cutters all of which are lots of metal removal and therefore in the category of reshaping.  It just seems to be in the nature of turners to push the boundaries on what tools can do.  That's not to say there aren't a set of standard grinds and profiles that are widely accepted and duplicated from one manufacturer to another...of course those exist but they're not typically the same and in fact very few gouge manufacturers make an off the shelf swept back wing profile.  Most do a standard straight across grind with a bevel at 45 deg and leave the user to sweep back the wings.

So I guess what I'm saying is that once one is really ensconced in turning there is a genuine need to shape on a pretty frequent basis.  I've come to realise that the T can indeed perform the task but it's not it's forte.  That is sharpening so I now reach for other methods to shape but then feel confident I'll never match the sharpness of a water cooled edge once the heavy lifting is complete.  The other great advantage of the T in sharpening is it only takes a tiny amount of metal off so it does preserve the longevity of turning tools and frankly they're not cheap so that's a result.

[Ken S]

Excellent post, Rob, and well reported "from the trenches".

I certainly agree that the Tormek's forte is sharpening rather than reshaping. I am in favor  of using "the right tool for the  right job" (quoting Engineer Scott). Sometimes that means tools.

Time to pick up my grandchildren from school.

KEN