Author Topic: Which stone for faster grinding?  (Read 1104 times)

Offline Ben H

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Which stone for faster grinding?
« on: March 23, 2020, 09:28:26 pm »
Hi! This is my first post on the forum. I bought a T-8 about six months ago and have discovered I love sharpening. Chisels and plane irons are quite straightforward. Knives are a real challenge, but I’ve learned a lot, mostly from Vadim’s postings and videos. I recently bought the SVH-320 planer blade jig, and I’m using it with the standard wheel (SG-250). As others on this forum have discovered, it takes a long time. The first blade I ground had a nick about a centimeter deep, and I spent a total of five hours, over several evenings, working on it (great result!). The second blade was less damaged, and I graded and trued the stone more often, so it took about half as long. Unfortunately, I don’t have a slow-speed grinder (yet). Instead, I’m wondering whether it would be worth buying a coarser wheel for the Tormek, to speed up the rough work on badly damaged planer blades. Perhaps the SB-250? Or a CBN wheel? I’m thinking that an 80 grit CBN wheel will not only be faster than the coarsely graded (220 grit) SG wheel in terms of its coarser grit but also because it would eliminate all the time spent grading and trueing. Any advice would be appreciated!

Offline Even

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Re: Which stone for faster grinding?
« Reply #1 on: March 31, 2020, 10:37:38 am »
Hello.
I use the SB-250, as I have found this one to be the fastest.
Have tried the DC-250 but don't think this one was faster.
Has CBN # 80 and # 160 but have not tried this as Knife grinders do not recommend grinding at a greater angle than 35 degrees as this can strip the wheels.
My planer blades are often at 40-45 degrees.

If I need and remove a lot of metal I mount the jig on a high speed grinder and set a 35 degree angle.
Then it's easy for me to grind a 40 degree angle on the tormek afterwards.

Most planer blades I have can be grinded on a high speed grinder if you are careful with the heat, as they are often made of HSS steel.
I want to invest in a CBN wheel to mount on the high speed grinder, so that it will go even faster and less heat, then set the angle of 30 degrees so im not striping off the CBN coating.

Even

Offline Ben H

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Re: Which stone for faster grinding?
« Reply #2 on: March 31, 2020, 12:09:40 pm »
Thanks for this very valuable information, Even! As I was unaware of the 35 degree angle limitation, I had pretty much decided I would buy an 80 grit CBN wheel for sharpening planer blades. I didn't understand the difference between 'ordinary carbon steel' and 'HSS', but having now read the information on the 'SB-250 Tormek Blackstone' page of the Tormek site (https://www.tormek.com/uk/en/accessories/grinding-wheels/sb-250-tormek-blackstone-silicon/), I see that the blackstone is recommended specifically for the shaping of HSS planer blades and woodturning skews.

From what I have read on this forum, there are at least a few people who have been disappointed with their purchase of the Tormek SVH-320 planer jig. I am a hobby woodworker, so it was difficult for me to justify the price of the planer jig. Ultimately, I guesstimated the payback period by weighing the cost of the jig against the cost of having the blades sharpened professionally. (In the interest of complete transparency: I am also considering the possibility of offering sharpening services as a sideline business.) Had the Tormek website (https://www.tormek.com/uk/en/grinding-jigs/svh-320-planer-blade-attachment/) stated something along the lines of 'the Tormek Silicon Blackstone wheel will be needed to obtain reasonably quick sharpening of badly damaged planer blades', I would have factored in the cost of the additional wheel when making my calculation. I believe Tormek is likely a company that makes the bulk of its sales to repeat customers, i.e. those who already have the machine and come back time and time again to buy accessories and consumables. If this is true, it is essential that Tormek not only present its products commercially (i.e. in a manner designed to convince potential customers to buy them) but also with maximum transparency (i.e. providing complete and detailed information to help customers determine whether a product will meet their needs and, most importantly, to prevent disappointment (which may turn off loyal customers to Tormek as a company).

I work with a lot of used wood, which despite my best efforts occasionally contains nails or broken off screw tips. Damaged planer blades and saw blades have been a fact of life for me. I guess it's time I invest in one of those handheld metal detectors that I've read about elsewhere here on the forum.

Ben

Offline jvh

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Re: Which stone for faster grinding?
« Reply #3 on: March 31, 2020, 07:30:21 pm »
Hello,

a little bit off topic but did you ever consider to buy a Helical cutter head for your planer?

Total costs can be less than a sharpenning jig & wheel(s). Planing quality is much better with such cutter head and carbide inserts have uncomparable better lifetime (20x) against HSS blades.
And if you "find" a nail inside wood you can just 3x turn the damaged carbide insert and then replace it easily.

I have this one (spiral) and I wouldn't go back to HSS blades anymore...


jvh

Offline Stickan

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Re: Which stone for faster grinding?
« Reply #4 on: April 28, 2020, 08:12:04 pm »
Hi,
There is no limitation that you cant sharpen over 35 degree angle. Sharpening scissors means that you are up around 60 degrees.

Best,
Stig


Offline RickKrung

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Re: Which stone for faster grinding?
« Reply #5 on: April 29, 2020, 02:38:18 pm »
Hello,

a little bit off topic but did you ever consider to buy a Helical cutter head for your planer?

Total costs can be less than a sharpenning jig & wheel(s). Planing quality is much better with such cutter head and carbide inserts have uncomparable better lifetime (20x) against HSS blades.
And if you "find" a nail inside wood you can just 3x turn the damaged carbide insert and then replace it easily.

I have this one (spiral) and I wouldn't go back to HSS blades anymore...


jvh

Your machine is different than my "lunchbox" planer (DeWalt 735), so maybe that explains the difference.  On the one they show for my planer, the carbide inserts are not adjacent, as in your cutter head.  That leaves me wondering how well works for mine.  A question for the SHELIX people, for sure, just mussing about it here. 

Your cutter head.


Mine.


Rick
Quality is like buying oats.  If you want nice clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.