Question about bevel angles

[vortex]

Hello,

I bought my first Tormek (a T7) a month or so ago, and I have found it to be excellent in all respects and fairly straight forward to use, (mostly chisels and bench plane blades) but I do have a few questions...

1. By hand on water stones, I would sharpen a 25 degree primary bevel and a 30 degree secondary, for example. Do I need to use this primary/ secondary bevel system with the Tormek, or just put a 30 bevel  on the whole thing because it's just as fast on the machine to do the entire bevel?

2. I read somewhere that it is a good idea to add a couple of degrees to the grinding angle to provide extra support to the hollow bevel. Is this correct?

3. Once I have ground my tools on the coarse and then fine grades, I assume I just need to keep the stone fine graded for regular sharpening on undamaged blades, but will the stone remain graded at the fine state, or will I need to continually use the fine side of the stone grader to maintain the grit?
What I am trying to say is, does the stone eventually return to a coarse state when it has been set with the fine side of the stone grader or does it remain fine until regraded as coarse?

Thanks in advance

Ellis.

[grepper]

Not seeing anyone else reply, so I'll try.

1.  I think the bevel you choose is to your preference.  You know, a thiner bevel is going to cut more deeply with less effort etc.  I'm not a woodworker, so maybe there is a better answer, but that's my guess.

2.  With any decent steel I wouldn't think it would make that much difference.  Compared to a flat grind, the 10" (250mm) wheel is not all that hollow grinding.  If the edge does not hold up like you think it should, add a degree or two.  Experiment!

3.  From my experience the wheel needs occasional dressing to keep it at whatever grit level you have established on it.  Now, if memory serves me correctly, Jeff said the wheel will get rougher as 250 grit is it's normal condition.  Hopefully I don't have that backward!  Sometimes I like to have the wheel somewhere between rough and smooth.

With just a little use, you will have this all figured out anyway!

Hope my pot shots at your questions are helpful.

[Herman Trivilino]

Hello,

I bought my first Tormek (a T7) a month or so ago, and I have found it to be excellent in all respects and fairly straight forward to use, (mostly chisels and bench plane blades) but I do have a few questions...

Hi Ellis.  Welcome to the forum.

1. By hand on water stones, I would sharpen a 25 degree primary bevel and a 30 degree secondary, for example. Do I need to use this primary/ secondary bevel system with the Tormek, or just put a 30 bevel  on the whole thing because it's just as fast on the machine to do the entire bevel?

You're thinking along the right lines.  It is a matter of preference but there really is no need for that secondary bevel.  Of course it will make it faster to sharpen in the future if you do have the secondary bevel, so for that reason some people like to use it. 

2. I read somewhere that it is a good idea to add a couple of degrees to the grinding angle to provide extra support to the hollow bevel. Is this correct?

You can experiment with different bevel angles.  You'll find that changing it a couple degrees one way or the other will make a difference, but as to whether that difference is an advantage or a disadvantage depends on the type of wood you're shaping and the type of work you're doing.  If you get the angle too small the edge breaks off, too blunt and you have to push harder to cut.  You just have to experiment and find what you like.

3. Once I have ground my tools on the coarse and then fine grades, I assume I just need to keep the stone fine graded for regular sharpening on undamaged blades, but will the stone remain graded at the fine state, or will I need to continually use the fine side of the stone grader to maintain the grit?
What I am trying to say is, does the stone eventually return to a coarse state when it has been set with the fine side of the stone grader or does it remain fine until regraded as coarse?

You have to keep regrading the grindstone.  It won't stay fine and it won't stay coarse.  Pieces of metal get embedded in the surface and grading removes them.  Plus, the grains break, and they break away.  So large grains will break up into smaller ones, and smaller ones will fall away exposing larger ones.

[Ken S]

Welcome to the forum, Ellis.

I wouls suggest you forego using the secondary bevel technique with your new Tormek.  Learn to use the Tormek with the recommended coarse grind, fine grind, and leather honing wheel with a single bevel.

Once you are very proficient with this method you will be able to decide if you prefer the single bevel honing wheel method or finishing off your tools with fine stones and a double bevel.  The answer may be "it depends".  Give yourself the skill required to make an intelligent choice based on proficiency with both methods.

The hollow grind effect is less of a factor with ten inch wheels.  I would be more concerned with whether you are using the chisel being struck with a mallet or being pushed by hand.  Also how hard the wood is.

Keep your wheel refreshed frequently with the stone grader.

Spend some time really getting to know the Tormek and one chisel.  Three quarter inch more or less is a good learning tool.  It is less steel to flatten and polish (the back) and wide enough to fit easily in the jig.  Really learning one simple chisel will teach you a lot about the Tormek.

Keep us posted.

Ken

[vortex]

Thanks for the replies, and the great advice, and sorry for the dumb questions!

I have had a play around with an old 1 inch chisel, which came out so well, I thought I must have been doing something wrong!

On a related theme, polishing the bevel on the leather honing wheel was no problem using the jig, but when I come to remove the burr on the back of the blade, is there a trick or technique to not rounding the back over at the edge, or is it just a case of go slow and watch carefully?

Ellis