looking for more aggressive than stock SG250

[ZedMek]

I find that it takes a very long time to do anything more than modest regrinding the apex of a knife.

If I have to change the overall curve of a knife edge it takes very long.
Also after I use my bench grinder to grind off the part of a solid bolster left behind from many previous grinds( the swale), then it also takes a long time to reshape the curve of the edge.

So I think a coarser grit wheel would be faster?
Are the diamond wheel the only option or are there stone wheel that are appropriate?

[Ken S]

Welcome to the forum, ZedMek.

Starting with the most basic option, when you have to do heavier grinding, refresh your SG-250 with the TT-50 Truing Tool. This will make your wheel more coarse than the stone grader.

Tormek makes two grinding wheels designed for heavier grinding. The SB-250 blackstone is the traditional choice for harder steel alloys and heavier grinding. It now seems overshadowed by the DC-250 coarse diamond wheel. If you read this before the Monday morning live Tormek online class, be sure watch it. After the live class,Tormek will include it on its youtube channel. This class covers the new series of diamond wheels for the T4. Except for the wheel diameter, the wheel information is the same.

The DC-250 is Tormek's most aggressive wheel.

Ken

[RickKrung]

Beyond strictly Tormek are:

1) Belt sander, particularly if variable speed and can be slowed really low,
2) Traditional grinding wheel (at least 8" on a T7/8 machine),
3) Slow speed bench grinder (~1750 rpm) (Rikon in my case) with the matrix grinding stone (don't know what it is called),
4) CBN, either on a bench grinder and/or the 10" on the T7/8s.  (8"ers are available for T4s).

I have all four.  Controlling head, particularly right at the apex is difficult with the slow speed grinder.  Traditional grinding wheel adapted to a Tormek machine works pretty good and preserves the water-based grinding process.  Variable speed belt grinder is great also.  It took special adjustments to the speed pots on the circuit board to achieve the really slow speed, but that could compromise the warranty.  It also too special setups to be able to use the Tormek jigs and platforms, so the belt grinder option may take some additional work to get it up and going.  I have only recently started using CBN, on both the slow speed bench grinder (80 grit) and a 10" one at 180 grit (Woodturners Wonders) on my T8.  I liked both for their grinding action, but do not like the grinding grit/dust from the bench grinder.  I follow the CBN with the Tormek diamond wheels and SJ wheel, depending on what objective. 

Rick

[cbwx34]

I find that it takes a very long time to do anything more than modest regrinding the apex of a knife.

If I have to change the overall curve of a knife edge it takes very long.
Also after I use my bench grinder to grind off the part of a solid bolster left behind from many previous grinds( the swale), then it also takes a long time to reshape the curve of the edge.

So I think a coarser grit wheel would be faster?
Are the diamond wheel the only option or are there stone wheel that are appropriate?

One thing I learned is to not sharpen on the Tormek like you would a belt sander or grinder.  Leaving the knife on the stone longer (since it's water cooled) makes the grinding go alot quicker.

Also, if you don't already, it's worth it to learn to freehand sharpen on the wheel to make some repairs.

And if you're reshaping an edge, try doing it at a much higher angle, (freehand or with a jig), then when it's where you want, lower it and sharpen in an new edge at the appropriate angle.  This also speeds up the process.

[ZedMek]

cbwx34, RickKrung, Ken S, Thank you for your well considered replies.

I am new to sharpening and don't have a belt machine or experience in freehand sharpening yet. So I think for now belts are not an option.

Ken S: At the moment I am doing mostly medium quality home kitchen knives, so not hard and exotic materials. It seems that is mostly the benefit of the SB250? Or is the SB250 faster on standard Stainless Steel than the SG250?

So from your three answers it seems that the diamond wheels are my preferred choice at the moment.

I will look at the YouTube recording of the Tormek live session.

[RickKrung]

I see it a little different.  Early on, I was also frustrated similarly by slow progress when having to take a lot of metal off.  I got the SB wheel hoping that would change things.  It didn't.  Then when the diamond wheels came out, I got all three.  Even the coarsest one, DC-250, was a disappointment for me. 

At that point, before I went for the belt grinder, the most effective, fast metal removal wheel was a traditional grindstone mounted on my T8.  Even though only 1" wide, it works quite well and at under $100 is quite affordable.  The challenge is adapting the bore to the 12mm Tormek shaft.  Most grindstones come with plastic bushings to fit different "inch" sized grinder shafts.  It is possible to drill out PVC pipe to fit the 12mm shaft and I understand the OD of the PVC pipe mates well with the larger plastic bushings.  This has been discussed here in several historic threads.  The first traditional grindstone I used was a Norton 3X 84 grit but I now have a 10" dia. "no-name" one that was my go-to before getting the CBN wheels. 

In my view, if you cannot afford a belt grinder, you cannot afford a diamond wheel(s) AND, the latter may not even meet your need. 

While I've only just started using the CBN wheels, I am impressed.  Given that you already have a bench grinder, the  6" or 8" 4-in-1 PLUS CBN Wheel from Woodturners Wonders could be a good middle-of-the-cost-road alternative.  I have the 8", 80 grit one. 

Good luck. 

Rick

[cbwx34]

...

In my view, if you cannot afford a belt grinder, you cannot afford a diamond wheel(s) AND, the latter may not even meet your need. 

...
Rick

I agree... I would invest in a belt grinder first.

Take a look at SteveB's video on the subject...  Equipment: Belt Sander... which he uses along with a Tormek.

But as I said before, also look at improving your results on the stock wheel first.

[RickKrung]

...

In my view, if you cannot afford a belt grinder, you cannot afford a diamond wheel(s) AND, the latter may not even meet your need. 

...
Rick

I agree... I would invest in a belt grinder first.

Take a look at SteveB's video on the subject...  Equipment: Belt Sander... which he uses along with a Tormek.

But as I said before, also look at improving your results on the stock wheel first.

That is a very good video on the benefits and usage of a belt grinder for knives.  He does or used to sell the Viel belt grinders and offers(ed) a kit for mounting the PSI variable speed motor with smaller drive pulley.  This is the route I went, but mounted the PSI motor differently. 

Rick

[Herman Trivilino]

I find that it takes a very long time to do anything more than modest regrinding the apex of a knife.

You are not grading the grindstone properly. Apply the coarse side of the stone grader with a lot of force and for enough time to refresh the grindstone. If necessary, use the edge of the stone grader.

[ZedMek]

Rick, there are a couple of topics here, I want to be sure I understand:
- Did you say that the Norton and No-Name wheel were better than the stock SG250 for fast material removal?
- 80 CBN or the Norton or the No-Name is good to use right before the SG250, it is an acceptable progression of grits?
- The  8" CBN's on a bench grinder is better than the 10" Norton and No-Name for fast material removal?

Please tell me if the above is incorrect, I'm trying to understand, not put words in your mouth!

In the end though I would like to get faster material removal on my Tormek.
(I'd prefer that to a belt or bench grinder,) so I'm trying to figure it out. I'm trying to figure out : Stone or CBN or Diamond, and if so, which one?

Could you give some more specs or sources on the Norton and N-Name? Mounted on the Tormek, Correct? (mounting isn't an issue for me, I'm a machinist)

......fast metal removal wheel was a traditional grindstone mounted on my T8.  Even though only 1" wide, it works quite well and at under $100 is quite affordable.  .........
......The first traditional grindstone I used was a Norton 3X 84 grit but I now have a 10" dia. "no-name" one that was my go-to before getting the CBN wheels. 

While I've only just started using the CBN wheels,....  ....the  6" or 8" 4-in-1 PLUS CBN Wheel.......... I have the 8", 80 grit one. ...

[RickKrung]

Rick, there are a couple of topics here, I want to be sure I understand:
1) - Did you say that the Norton and No-Name wheel were better than the stock SG250 for fast material removal?
2) - 80 CBN or the Norton or the No-Name is good to use right before the SG250, it is an acceptable progression of grits?
3) - The  8" CBN's on a bench grinder is better than the 10" Norton and No-Name for fast material removal?

Please tell me if the above is incorrect, I'm trying to understand, not put words in your mouth!

In the end though I would like to get faster material removal on my Tormek.
(I'd prefer that to a belt or bench grinder,) so I'm trying to figure it out. I'm trying to figure out : Stone or CBN or Diamond, and if so, which one?

Could you give some more specs or sources on the Norton and N-Name? Mounted on the Tormek, Correct? (mounting isn't an issue for me, I'm a machinist)

...snip...

Nice that you are a machinist (I am too).  It will serve you well with the Tormek. 

I've numbered your questions above, for reference, but essentially, YES to all three. 

#1 - Yes

In regard to #2, grit transition, I think the objective is to achieve faster metal removal, irrespective of the finish pattern/quality.  In that sense, I think it doesn't matter.  You get the metal off (and create/recreate an actual bevel) that you want with the coarse medium and remove the heavier grinding marks as you refine the bevel once you start with whatever you're going to use on the Tormek, be that SB, SG, SJ, or DC, DF, DE, SJ, or insert CBN wherever.

#3 - Yes, but there is no Norton 10", only 8".  The No-Name is the 10".  I can't help with anything about the No-Name.  It was a gift and is completely without labels or printing to reveal maker, grit, medium type, etc.  All I know is, it works great on the T8 as much because it matches diameters.  The 8", 80 grit CBN wheel I have on my Rikon bench grinder is by far the most aggressive with metal removal of all the grinding wheels I have.  I think the belt grinder can be faster still. 

As a machinist, you should be able to turn a bushing to match the stone arbor hole and 12mm bore for the Tormek shaft.  I highly recommend using stainless steel.  Somehow, I didn't on one of the two Norton wheels and it has rusted such that I will not use it. 

Here is a link to info on the Norton 3x wheels, which is about all I know about them. 

Rick

[Ken S]

Zedmek,

I would like to include my thoughts about the Norton 3X wheels. I did not include them in my earlier reply because I did not know that you are a machinist. Over the years of email corresponding, I have come to hold Rick in high regard. I do not have his machinist skills. Where you or Rick would machine a proper bushing, I would "ream out" a piece of 5/8" plastic pipe with a 31/64" drill bit and some jiggling. I have posted this before. as it seemed to generate little interest, I have thought our members preferred "plug and play" grinding wheels, even if the cost was considerably higher.

The 8" diameter Norton grinding wheels cost in the $50 to $60US range. They are available in 80 or 46 grit. There are two constraints with mounting them on a Tormek.
(Both are easily overcome in a home workshop and child's play for a machinist.) The bore is 1". Norton supplies reducing bushings to 5/8". I reduced this to 12mm with my drill press. Not quite machine shop tolerance, but very usable.

The second constraint is the 1" thickness of the 3X wheels. 12mm Inside Diameter fender washers (preferably stainless) make quick work of this

A third possible constraint is using an 8" wheel with a larger Tormek. This is an exact fit wiith the T4. It is also as good a fit as any T8 wheel worn down to 8" (200mm) with the larger Tormeks.

Tormek likes universal wheels. The SG wheels used with the stone grader typify that philosophy. The 3X wheels do not fit into that philosophy. They are designed for heavy grinding. They require some fitting, which is more bother than many users want to do. For those who are willing put in some effort, the 3X wheels offer a lot of firepower at very low cost. At around $60 (and you only need one), they are a fraction of the cost of a good belt grinder, diamond or CBN wheels. They run cool with water and create no dust or sparks.

Ken

[ZedMek]

Thanks Rick and Ken.

[Arthur]

For rough work I use METABO grinding wheels 60 grit and NORTON 100 grit. The METABO grinding wheels are available in 10 "sizes. Recommend.

[RickKrung]

Can you provide any specs on the wheel and/or type of wheel that you are using, please?  I went to the Metabo website.  The make a lot of stuff and a lot of grinding/cutting discs, but I could not find grinding wheels. 

Rick