chisel sharpening

[bobl]

As you know, I am a knife sharpener and not a chisel sharpener.
a few years ago, when I got my T7, I had a customer who asked if I can sharpen chisels. I was at this time proficient with the T7 on knives professionally.  I thought I could add an extra string to my bow by sharpening chisels too. So, I looked at the videos for the Tormek T7 for sharpening a chisel. I thought I did a great job. Until the builder told me that I had not added an extra bevel from the main edge that the Tormek had made.
( Why did the video not do or show this )
Consequently, I have been turning away chisel work. 
The Video shows that you just need to sharpen one angle and not to put a second edge at a slightly higher angle.
I have asked builders and some woodworkers if the chisel should have one angle and one edge or one angle and 2 edges. They all said the chisel should have a one angle and a small bevel on the end of the chisel. 
Can I ask why all the tormek training videos do not tell you this???

[Ken S]

Excellent question, Bob.

The second bevel, often called a secondary bevel or micro bevel, is more useful with hand sharpening than with the Tormek. The secondary bevel is added so that the sharpener only has to sharpen (remove steel) from a very small area of the blade, generally around one thirth second of an inch instead of across the entire bevel. When sharpening with bench stones, the labor saved is considerable. When the edge needs to be resharpened, only the secondary bevel touches the sharpening stones. Eventually this tiny bevel becomes larger,, and it is time to regrind the main bevel.

The practice is very ingrained with woodworkers. However, with a Tormek, the grinding is easy enough that the secondary bevel is unnecessary. Tormek has graditionally recommended a single bevel. It is easy enough to add a secondary micro bevel with the Tormek. After the initial bevel is ground, just raise the jig by one turn with the microadjust and use the wheel with the stone grader set to fine. Finish up with the leather honing wheel as usual, and, presto, you have a secondary bevel!

If the customer requests and or expects a secondary bevel, I would just follow his wishes. The ironic thing is that if the customer plans to do minor sharpening between grindings, starting from no secondary bevel will give him a smaller base, which means longer between grinding. So.....give the customer what he wants and collect your fee. With either method you are giving him a superior edge.

Ken

[Herman Trivilino]

Just to add to what Ken said, let's suppose that a bevel angle of 25° is desired on a chisel. Let's consider three options:

Option A: Grind the entire bevel at 25°, with no secondary bevel.

Option B: Grind a secondary bevel 25°, which would require that the rest of the bevel, that is the primary bevel, be ground at something less than 25°. This will work well for a user who wishes to be able to sharpen the chisel later by hand. As Ken said, he will have an easier time of it as he will have less steel to remove. He will need to grind only the secondary bevel.

Option C: Grind the primary bevel at 25° and the secondary bevel at something more than 25°. This means the chisel will not have a 25° angle where it counts, at the tip. If this is what the user desires then he could request that the chisel be sharpened at that smaller angle, say 20°, and go with Option A or B.

Note that if the user is also a Tormek user, there is no need for a secondary bevel as all sharpening will be done on the Tormek. The Tormek user manual mentions this.
 

[Ken S]

Bob,

Just this week I downloaded a new DVD which would be useful for you. Does your sharpening library include Ron Hock's book, The Perfect Edge? (If not, it should.) Ron Hock manufactures plane blades and associated items. He is an expert in the field with decades of experience. He has just done a DVD (90 minutes) related to sharpening. He discusses sharpness in depth, tool steel, heat and cold treating, and then goes into sharpening. The video focuses primarily on woodworking tools rather than knives. However, if a woodworker is willing to pay you to sharpen chisels, this information is valuable to you in real money.

I purchased it, and recommend it highly. It is available in DVD form directly from Hock Tools or as an online download from Popular Woodworking. I did the download. I did not realize that "downloadable" meant that after I logged in, I could watch it as many times as I wanted online. (I had expected to download it directly to my ipad and watch it when no wifi was available.) In spite of this inconvenience, the information is solid, and well worth the price $25 or $30 US.

There is a short free preview on the Hock Tools site. I suggest you make sure the MP4 format is compatable in the UK.

Ken

[grepper]

The VLC media player, available for both PC and Mac, plays just about any video format you can throw at it, including MP4 and DVD's.  It even plays audio files like Wav and CD's.  You have to be trying to play something pretty obscure if VLC won't play it.

I've used it for many years.  It's a great media player and it's free.

http://www.videolan.org/vlc/index.html

[Ken S]

Grepper, you're a handy guy to have around.

Ken

[Waterstone]

While sharpening chisels on the Tormek, a micro bevel won't be needed at all. In the opposite a micro bevel will take away one of the biggest benefits the Tormek offers. It's the ability to do the honing work freehanded by using both edges that the hollow grind produces as registration areas on the flat honing medium. The honing work after the Tormek sharpening is absolutely necessary to get the chisels best performance and the best edge durability. Doing this by using the hollow grind is a quick and foolproof freehanded action.

I'm used to sharpen my chisels for years this way and am rather sure that they perform at their best.

Klaus

[Ken S]

I don't think the real issue of this topic is whether or not a micro bevel is necessary. The situation is that the customer expects a micro bevel, and the customer is paying the bill. Right or wrong, the customer wants a micro bevel.

Ken

[Waterstone]

Basically I agree, Ken.

But if you explain to the customer that in this case a micro bevel is a disadvantage for himself, he possibly will think about it. The customer himself will enjoy the ability to hone the chisel many times until a new sharpening on the Tormek will be needed by taking advantage of the hollow grind. It's so much easier to refresh the edge this way than to refresh a micro bevel freehanded.

Klaus

[Ken S]

Klaus,

I am an old chisel sharpener, as I suspect you are, too. I think we are making the presumption that Bob's customer, the builder, would prefer to do the intermittent sharpening himself. This is not always the case. I know several carpenters who do not sharpen chisels. They buy inexpensive new "sharp" chisels and use them until they are "dull". At that point, or sometime later, they discard them and buy new "sharp" chisels. I agree with what you are thinking; this seems sinful.

As a knife sharpener, Bob has another set of skills, sharpening knives. With some study and practice, he can certainly become a proficient chisel (and plane blade) sharpener. At this point, I do not think Bob has acquired the knowledge to explain the situation to the builder. Frankly, I would not encourage the builder to do his own sharpening. I would sharpen his chisels for a fair business price, and offer an ongoing discounted price if he wants regular sharpening.

The builder may use contract labor, and have to provide tools for his workmen. In that case, he might prefer to contract the sharpening to a professional instead of paying his workmen to do a hit or miss job. If I were in Bob's situation, I would quickly become skilled sharpening chisels and plane blades, explain the micro bevel situation to the builder, and offer to sharpen them however he wishes. If Bob can get the follow up work, that's nice work, quickly done, and a nice revenue stream.

I am retired, and have never sharpened professionally. If I had a chance for this kind of work, I might be tempted......

Ken

[bobl]

Thanks Ken and all the guys, I now feel confident, as a result of your dialog, to go ahead and sharpen chisels. I honestly thought I was doing it wrong because of the builder. I now know it was the lack of experience to confidently rebut what he was saying. I now have the knowledge and I expect to add more value to my service now.

Here is a new one Ken.
A friend of mine who is a plasterer, had a couple of bad nicks in his plastering trowel, ( Must have caught a nail or badly used it )  he knows I am a knife sharpener and also has the Tormek T7  as well as other machines, so he asked me if I could sort out the nick.

You know, I tried so hard on the T7 to grind as opposed to sharpen this thing. I actually managed accidentally to put a sharp edge on it. However, he is so happy the edge has gone and he says the plastering is so much smoother because of it.

So, there is a new use for the amazing T7.

Any of you guys had an experience similar with a tool or object you wouldnt have thought possible.??
 
 

[bobl]

That should have said
I also HAVE the T7
Not HAS.
Whoops.

[Ken S]

Bob,

Good work with the plastering trowel. It makes me think of an early topic I found on the forum. The poster asked if we can sharpen drill bits with the Tormek. Jeff, the founding moderator replied, "Not yet". I have long thought that the primary constraint with the Tormek is a timidity of imagination.

We now have the DBS-22, which does an amazingly versatile job with drill bits. Compared with the earlier jigs and accessories, Tormek's engineers have done some astounding work. I am convinced that their chief constraint (which forum members do not have) is the discipline imposed by staying afloat in the business world.

One of the primary shifts I have seen in the forum since I joined in 2009 is growth from just using the Tormek well as designed to modifying and adding to both the components and techniques. The really exciting part is the compounding effect added by sharing these ideas with other members.

Dutchman posted his grinding angle booklet several years ago. His inspiration has sparked a whole movement in how we set up bevel angles.

Robin Bailey designed and sells an oversized universal support bar which has expanded the scope of possible work. Robin did this to solve a problem sharpening cleavers and knives.

Herman developed his very versatile small knife platform. This originated from a poster with a problem sharpening small knives. Herman and others have used this jig from everything from very small knives to machetes. One of these homemade jigs should be part of every Tormeker's kit. We are far from achieving its full potential.

The list goes on and on. We are a global team. Ideas bounce around from Australia to the Czech Republic, to France, literally all over the planet, picking up refinements along the way. The latest idea I am presently watching is a you tube from Sandor, a new member (and very experienced and innovative knife sharpener) from Slovakia. His machine for testing edge retention by cutting rope is truly amazing.

Bob, buckle your seat belt; I believe we have only seen the tip of our sharpening innovation iceberg.

Ken

[Herman Trivilino]

Elden has posted previously about "sharpening" drywall knives. What you are calling plastering knives. The edge must be straight for the tool to work properly.

As to the issue of the micro bevel, or secondary bevel, on the carpenter's wood chisel. I would think that if the carpenter wishes to be able to sharpen the chisel himself with just a bench stone then he would want the secondary bevel to make that job easier. Once the chisel has been sharpened that way a few times it will become more and more difficult. This is when it will need to be taken back to the Tormek. Repeat business!

[Rob]

While sharpening chisels on the Tormek, a micro bevel won't be needed at all. In the opposite a micro bevel will take away one of the biggest benefits the Tormek offers. It's the ability to do the honing work freehanded by using both edges that the hollow grind produces as registration areas on the flat honing medium. The honing work after the Tormek sharpening is absolutely necessary to get the chisels best performance and the best edge durability. Doing this by using the hollow grind is a quick and foolproof freehanded action.

I'm used to sharpen my chisels for years this way and am rather sure that they perform at their best.

Klaus

In fact, by resting the chisel on a fine stone at the two touch points created by a hollow grind (the edge and the other end of the arc described by hollow grinding) you are in fact honing a very fine micro bevel without realising it!  So it's not the opposite benefit as you've stated, it is in fact a benefit of hollow ground tools in general (not specific to the Tormek, rather specific to any wheel based grinding system that yields a hollow grind).  The benefit is simply that a hollow ground bevel creates two touch points, that in turn means the bevel wont rock when you're moving it on a fine hand stone, in fact it positively registers on those two "high points" and that presentation angle certainty allows a uniform micro or secondary bevel to be created at the very tip of the edge.  This may be so small that you don't see light reflecting off it so it doesn't seem like a micro bevel but that's exactly what it is and if you go steady each time you re-hone it, you can go for months without regrinding the primary bevel.

I strongly recommend this rather than Tormek's manual approach which suggests regrinding the primary bevel every time.  The reason is that with some plane blades (eg Lie Nielsen or Veritas tools) they often have super hardened blades and regrinding the entire bevel is not a simple or quick task.  It's a heck of a long time of finger aching grinding whereas if you'd gone with even a small micro bevel you'd get the job done in no time.

Micro bevels are a good thing on many levels and I'm not surprised your customer is asking for one :-)