looking for more aggressive than stock SG250

[jungbluta]

Hi,

I see several 10" grinding wheels on Amazon (including Norton), here are a couple:

https://smile.amazon.com/Norton-Aluminum-Oxide-Straight-Grinding/dp/B07H9JMTWN/ref=sr_1_5?dchild=1&keywords=10%22+grinding+wheels&qid=1633536551&sr=8-5

https://smile.amazon.com/61771-Grinding-Aluminum-Diameter-Maximum/dp/B0742N49TX/ref=sr_1_16?dchild=1&keywords=10%22+grinding+wheels&qid=1633536648&sr=8-16

Thanks,
Andy

[Ken S]

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.



Good posts about an interesting topic.

Grinding wheels are like mill files. My files are some of my most used tools. I usually prefer the finer cut (smooth or second cut) to the coarser garden variety bastard cut (the correct, accepted term for this cut).
These cuts leave a smoother finish and work better with harder steels.

Yes, coarser grit wheels cut more aggressively than the 220 grit SG-250, just as a bastard cut file is more aggressive than a smooth cut. This faster cutting vs smoother finish debate is nothing new for Tormek. Back when I was still using oilstones, Tormek introduced the aluminum oxide SuperGrind (SG) wheels. Although not overly aggressive, it cut faster than the original natural sandstone. Many years later, Tormek introduced the silicon carbide SB blackstone with very little fanfare. Like the SG, the SB only had a maximum grit size of 220. Tormek has never chosen to make a coarser grinding wheel than 220.

Assuming that 220 grit was our point of being too slow for heavy grinding, what would out maximum point be? I have  tested Norton 3X 80 and 46 grit wheels. The 46 grit cut around 20% faster, although both were impressively aggressive and left surprisingly smooth surfaces. For occasional use, I would recommend the 80 grit. We do not have agood selection of coarser grinding wheels, especially from Tormek. I always prefer to buy Tormek. In this case, Tormek has not given us that choice.

Personally, I do not like some of the other options. In my opinion, half speed grinders are still high speed. Like belt grinders and any wheel used dry with a Tormek, all create dust. I have a dry grinder, which has sat on a shelf for years. I have the BGM parts, but have never put them together. I also have two belt grinders. They are useful tools; however, even with a variable speed motor, they still can run hot.

I spoke with a Norton rep several years ago. Norton will make custom grinding wheels. A 250mm 3X would solve the problem. The only problem would be the 500 wheel minimum order........

Ken

[Arthur]

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

look at here
https://www.metabo.com/us/enus/accessories/sanding-polishing/accessories-bench-grinder/grinding-discs-aluminum-oxide/

[Ken S]

As much as I like Norton products, I would lean toward the 60 grit wheel.

Ken

[ZedMek]

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

Thanks Arthur, could you provide the part number for the Metabo? Anytime I start looking at abrasives I get lost in all the details ( type, grit, hardness, etc)
I just ordered a Norton 3X based on advise from here but it is only 8".

I'd like to know what the good 10" option is.

[BeSharp]

Beyond strictly Tormek are:

1) Belt sander, particularly if variable speed and can be slowed really low,
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

The Tormek is a very safe machine, but it is SLOW. I've modified three of mine to run at around 154 rpm, but for a farmer's market, it's still too slow. Vadim at KnifeGrinders now has a coolant which allows grinding on a half-speed grinder without overheating the blade. 1,750 rpm versus 110 rpm is almost 16 times faster! Here's his video sharpening 22 knives in an hour: https://www.youtube.com/watch?v=KZ-1bFgsyRs

Results and conclusions of his 10 -video series on overheating are summarized in 29 pages here: http://knifegrinders.com.au/SET/Heat_in_Sharpening.pdf

In short, using his coolant on a half-speed grinder with a stone wheel offers speed,, at low cost, and without overheating. (He emphasizes he still uses Tormeks for high-end knives and folders).

I'm using the coolant on my Twice As Sharp scissors sharpener (3,400 rpm, 5" diameter, 120 grit) and it does help prevent overheating the tip of small scissors. I'm also using it on my stock Viel S-5 belt sander with an 1,750 rpm motor and a 6" drive pulley.

[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.

Thanks Arthur, could you provide the part number for the Metabo? Anytime I start looking at abrasives I get lost in all the details ( type, grit, hardness, etc)
I just ordered a Norton 3X based on advise from here but it is only 8".

I'd like to know what the good 10" option is.

look at this: Metabo 10" x 1-1/2" x 1-1/4" Vitrified 60 Grit Part #:   655424000.  Or Vitrified Wheel 10" x 1" x 1-1/4", Type 1, A60 (655421000). Attention, adaptation to the Tormek shaft is required.