Primary Bevel angle.............diamond stones???

[Nads]

Just have a few questions for you guys about re-establishing the primary bevel angle once the secondary bevel has got too big?

Firstly, how big do you let the secondary bevel get before regrinding the primary bevel, or how many times do can you re-hone the blade before restoring the primary bevel?

And, Secondly I find that when re-establishing the primary bevel on my A2 plane blades (and generally flattening chisel & plane iron backs) seems to take forever on my 800 grit waterstones, what might be another option? I don't want to use a bench grinder because of all the overheating problems, and a tormek is a bit out of my price range? So I was maybe looking at a diamond stone? Either the DMT Dia-Sharp Double X Bench Stone - 120 grit (axminster), or the DMT Dou-sharp - Course/Extra course - 200 grit (D&M tools), any advice on either product? What do you guys use for this job?

Thanks all

Nads

 

[dchenard]

You could either go down to a 220 stone, or use sandpaper on a flat surface. Silicon carbide paper in the 120 range will work fast (but the paper wears fast too).

But with a light touch and a friable (white or pink, depending on the manufacturer) wheel, grinding works great if the wheel is frequently dressed (once before any major grinding job) and you use a light touch. Works for me... And a fast grinder (3600 RPM) works fine, having a clean and dressed wheel is the most important factor.

DC

 

[Paul Chapman]

Hi Nads,

I find that if every three or four honings you work the primary bevel on a coarse or extra coarse stone, then the secondary bevel never gets a chance to get too long. This method should work well with what ever types of stones you normally use. Very quick and easy :wink:

Paul

 

[Alf]

Firstly, how big do you let the secondary bevel get before regrinding the primary bevel, or how many times do can you re-hone the blade before restoring the primary bevel?

I go on the basis that when the secondary bevel starts taking longer to hone than my impatient self can stand, time to regrind the primary bevel.

And, Secondly I find that when re-establishing the primary bevel on my A2 plane blades (and generally flattening chisel & plane iron backs) seems to take forever on my 800 grit waterstones, what might be another option?

O1 blades... :wink: Sorry, that's not helpful

I don't want to use a bench grinder because of all the overheating problems

Ah, that's like saying "I don't want to use a router because of the burning problems on inside corners" - it's just technique. There's discussion about using bench grinders in the archive somewhere - if you can't find it I'll have a look later. Basically I'm just repeating what Denis said; get a cooler-grinding wheel if you like, but the best bet is to use a coarse wheel (you're stock removing here; finish isn't important, and a coarse wheel will grind faster and therefore give the steel less time to heat up.) Also keep it unclogged by using a wheel dresser on it frequently, which also helps keep it running cool by letting it cut fast. Light pressure, plunge in water frequently if desired. It's worth learning how to do it, 'cos it's soooo much quicker and very useful.

Cheers, Alf

 

[bugbear]

Just have a few questions for you guys about re-establishing the primary bevel angle once the secondary bevel has got too big?

Firstly, how big do you let the secondary bevel get before regrinding the primary bevel, or how many times do can you re-hone the blade before restoring the primary bevel?

At the risk of answering a different question from the one you're asking, I suspect you're removing too much metal each time you re-hone the secondary.

You should be removing the bare minimum, both to reduce labour, and to maximise the life of the tool. A good reason to use sharpening jigs IMHO.

It also saves primary grinding time

BugBear

 

[Anonymous]

Nads.....just another opinion.

The focus I think should be to minimize stone time as much as possible. Diamond stones are expensive. And water stones dish too quickly.

With waterstones its often the case that the stone dishes whilst in the middle of a sharpening.....such that this dish will transfer a curve to your blade.

Sometimes that curve is just what your after, uno to fether your bench plane blade for example, but often its imposes too slight or great a curve.
There's definetly times when you don't want any curve what so ever.

So,,,bench grind as often as possible I believe to near burr, so that when the take your blade to the stones all it takes is just a few laps on the stone to kick the burr, thereby reducing wear to the stones and reducing that dishing problem. So, if you find yourself lapping away, getting sore hands on the stones, I'd say definetly regrind ! :wink: your just wasting your stones and time in having to re-flattern them.

Another simple trick to reduce wear on your stones is to increase the bevel angle between stones. .....ie. say you've got a 800 and a 6000 grit water stone. .....and say you've previously ground the bevel off the grinder at 25 degrees. Well, hone the bevel higher off the stones....eg. 28 degree's on the 800 grit to throw the burr, and then 31 degrees off the 6000 for your final polish.....because an increase in bevel angle means less steel to remove to get the same result.......means you'll end up with 1 main bevel and 2 microbevels I guess...but it doesn't matter....its just the final angle thats important (31 in that example)....just don't get it too high. 35 degrees is the highest I go. Probably could go a little higher. I don't know. (I'm talking about the bevel down bedded blades)

Grind with white ALO wheels. Jig it someway to maintain the bevel angle and monitor the heat build up with your finger. I've got a simple jig setup I use that works well to square off and grind the bevel of plane blades to burr. If interested I can get you a picture sometime.

 

[Derek Cohen (Perth Oz)]

I suspect you're removing too much metal each time you re-hone the secondary.

You should be removing the bare minimum, both to reduce labour, and to maximise the life of the tool. A good reason to use sharpening jigs IMHO.

It also saves primary grinding time

BB makes an important observation here. Nads, I am not sure how large you grind your microbevel. Mine are in the region of .25 mm (or there abouts - a glint of shiny metal is usually enough).

The other point that may be made at this stage is it is evident that there are many ways to skin a cat. That is, everyone has a favourite method of grinding a primary bevel. I sometimes use a 220 grit waterstone, as Denis suggested. I have also used a grinder, as Jake prefers. Of all, my choice is a belt sander. A 120 grit belt will run cooler than a grinder, and remove metal faster and more reliably than a waterstone. It was good enough for Tage Frid.

Regards from Perth

Derek

 

[ajbell]

Nads

I am in a similar situation to you -
I blame it all on Philly's Big Bash!

I was spending more time flattening my waterstones than
sharpening with them.

I went down the grinder route for the primary bevel -
I got a bit of overheating at the start but it gets better with
practice.

Doesn't answer your question though!

p.s. did you go on your furniture course?

andy

 

[Frank D.]

I've tried just about everything (sigh)... I think the key is finding what's most practical for you (considering what you already have and your budget, too!). Now I mostly use a grinder. I'll eventually get a sanding mill (like a big belt sander) but not just yet. As far as stones go, for the primary bevel, diamond stones work the fastest (by far) and are the easiest to maintain. They are expensive though, but I figure the time saved is worth the money for me. I have several diamond stones, including a duosharp. They wont last forever but still they are relatively durable (as I said, it's time saved vs money). If you do get a diamond stone get one with the coarsest grit possible. It will become les coarse with time anyway. I got the duo with coarse on one side and extra-coarse on the other. I use water stones or oil stones for the secondary bevel and for polishing (a very small third bevel). I also use the duo to flatten my water stones (once again, very quick and practical).

 

[Colin C]

If you want to get a daimond stone, have you looked at the eze-lap stones as I have had one of the 6" ones for about 10 years.

Tilgear do them for the best prices that I have seen

 

[dchenard]

Light pressure, plunge in water frequently

Apparently Alf, this is a no-no...Both the instructors at Rosewood and Leonard Lee in his sharpening book strongly advise against plunging in water because of the possibility of creating stress fractures at the edge.

This said, I still plunge the tool in water, but I do it more often so as not to get the edge hot to the touch. So far it seems to work. And as you said, a light touch is important.

DC

 

[Frank D.]

Hi Denis,
This question comes up every now and again. I think plunging is a no-no only if it amounts to re-quenching. There should be no problem plunging a blade in water if you don't let the temp get too high in the first place (thus I guess Alf's "frequently"). So when a blade gets too hot to touch, you can cool it faster by plunging than just by waiting around or placing it on a heat sink. It does help speed up the grinding process. The water on the blade also lets you grind for a longer period before the blade heats up again, and the evaporating water is a good way to tell the temp of the metal while you're grinding.

 

[Alf]

plunge in water frequently

Thus if you never let the blade get hot in the first place it's a non-issue.

Cheers, Alf

 

[Paul Chapman]

plunge in water frequently

Thus if you never let the blade get hot in the first place it's a non-issue.

Cheers, Alf

Thus use a hand grinder

Paul

 

[dchenard]

Hi Denis,
This question comes up every now and again. I think plunging is a no-no only if it amounts to re-quenching. There should be no problem plunging a blade in water if you don't let the temp get too high in the first place (thus I guess Alf's "frequently"). So when a blade gets too hot to touch, you can cool it faster by plunging than just by waiting around or placing it on a heat sink. It does help speed up the grinding process. The water on the blade also lets you grind for a longer period before the blade heats up again, and the evaporating water is a good way to tell the temp of the metal while you're grinding.

That was my understanding of the situation. That's why, when I was at Rosewood, I'd dunk my blade when the instructors weren't around :-$

With some steel types one has to be more careful. O1 can be a b... at times, especially when thin... #-o

DC

 

[dchenard]

plunge in water frequently

OK, my silly idea of the day... One could put the blade in the freezer, then no need to dip the blade for a while... :idea:

DC

 

[Alf]

Oooo, could you call it cryogenically treated then...?

 

[Derek Cohen (Perth Oz)]

Thus use a hand grinder

Paul, don't you believe it. I can, and have, burnt blades on my hand grinder. Mine can spin pretty fast. It is necessary to restrain one's enthusiasm and crank sedately.

Regards from Perth

Derek

 

[Alf]

It is necessary to restrain one's enthusiasm and crank sedately.

Or do your grinding at the end of the day when you're pooped... :lol: But it's true, it is easy to get carried away. On the other hand with a hand cranked grinder I feel better able to hold the blade closer to the wheel, so I feel it getting warm much sooner. Mileage may vary.

Cheers, Alf

 

[Anonymous]

Manual powered reminds me of this conversation over at sawmill creek.

http://www.sawmillcreek.org/showthread.php?t=43465

Maybe you could pull apart an old bike and make your own ...... grind your blades, and go for pleasent bike ride at the same time, even though it maybe raining outside...........maybe listen to some music. Sounds kinda theoropudic don't you think .:wink: