Sharpening Relationship

[ccarrolladams]

Since I joined The FOG we have discussed the need to have bits and blades sharpened. In a recent discussion a member mentioned that he had been pleased with the firm sharpening his planer knives, so he asked them to also sharpen some Festool blades. Apparently the service technician said that it was just as well he noticed that the teeth of that Festool blade are not equally spaced and therefore would have damaged his machine.

Well, I am not clear which of us earn a living working with wood and who works with wood for the joy and without any concern for return on investment.

When I was a child helping my grandfather Adams who I called "AhPa" he was a wealthy retired executive who decided to go back to methods used circa 1800 to build furniture. He had collected excellent hand tools of that period. So from an early age I understood the vital importance of keeping cutting tools appropriately sharp. Long before I bought a power tool and found I could make money building things from wood, I took great pride in my ability to sharpen hand plane irons and chisels.

As the scope of my woodworking business expanded I realized I needed a relationship of trust with the outside firm sharpening my saw blades, jointer/planer knives and router bits. In the days before carbide inserts became common, sometimes I questioned the benefit of having steel blades sharpened versus replacing them. When I moved to Southern California I was lucky that my power tool dealer introduced me to an experienced and talented sharpening service specializing in the professional woodworking trades. That fellow bought machines to sharpen carbide when it reached the market. Unfortunately 40 years ago he retired.

By then I had a business relationship with a large grinding service who handled end mills and other metal working cutters. When my woodworking sharpener retired, I asked them about doing that for my cabinet shop. It turned out they had been sharpening woodworking tools for the movie industry since the 1920s and moved into metal working as the aircraft industry expanded. Before I bought my first Festools that grinding firm owned and knew how to use CNC saw grinding machines ideal for sharpening Festool blades.

Personally I would run from anyone who could pick up a blade and not notice the teeth being unevenly spaced. There are many good reasons why Festool blades are designed as they are. Lots of other blades also have unevenly spaced teeth, so by now I fail to understand how a sharpening service could stay in business without learning how to grand such blades to factory-new condition.

 

[tvgordon]

I have to wonder why many woodworkers want their sharpening service to use CNC equipment. Many years ago I worked for a couple sharpening shops that used manual machines and had many customers say that the blades cut better than when they were new. Of course the teeth not being equally spaced would not be an issue with manual sharpening equipment. The second shop I worked in ended up adding a CNC machine, but that was mainly so they could increase productivity without adding employees. Many sharpeners in small towns can't justify spending tens of thousands of dollars on CNC machinery. I agree with you that's its important to search for an experienced and skilled sharpener.

Tom

 

[Stephen B]

I have to wonder why many woodworkers want their sharpening service to use CNC equipment. Many years ago I worked for a couple sharpening shops that used manual machines and had many customers say that the blades cut better than when they were new. Of course the teeth not being equally spaced would not be an issue with manual sharpening equipment. The second shop I worked in ended up adding a CNC machine, but that was mainly so they could increase productivity without adding employees. Many sharpeners in small towns can't justify spending tens of thousands of dollars on CNC machinery. I agree with you that's its important to search for an experienced and skilled sharpener.

Tom

How true Tom,
Whilst I sharpen my own chisels and hand plane blades, I take my saw, thicknesser and jointer/planer blades to a saw doctor in a nearby town. Fortunately this town has a strong saw milling industry, thus providing a choice of experienced saw doctors as we call them.

 

[ccarrolladams]

Folk, I believe it is vital that people in the business of woodworking, as well as metal working and paper cutting, have a relationship of trust with those sharpening the cutting tools.

All of the Festool circular saw blades we use today were designed well after CNC grinders became standard. This hardly means an experienced and talented person cannot manually maintain a Festool factory edge on those blades.

The thing is all of those experienced and talented grinders I have known the past 67 years have died, retired or program CNC machines. But remember, since 1950 I have been building custom cabinets in the Burbank and Pasadena region of Los Angeles County, CA. We have a massive concentration of woodworking businesses here. This allows several competitive firms with a bunch of CNC grinders to stay in business.

I am sure that a lot of woodworkers live in smaller communities where there is hardly enough business to justify the cost of CNC grinders. The cost is usually far more than a top of the line CNC nested router of a pressure beam saw. The problem is it takes several different CNC grinders to handle the range of woodworking bits, knives and blades. Some of the circular blade grinders also handle metal cutting blades well. Some of the planer knife grinders also sharpen paper cutter knives.

So I am sure in smaller markets there remain experienced, talented sharpeners. Chances are I have not met them which is hardly the same as thinking they do not exist.

The important thing is to remember that probably everyone owning woodworking tools needs to consider who will do the sharpening. When you try to make woodworking a business the relationship of trust with your sharpening vendor or vendors is absolutely vital. Should your business include mill work then you probably will own at least a couple of moulders, which will require custom-ground knives. That is a sub-specialty so it is common to use one firm for re-sharpening and another for making custom shaper knives.

I believe the best CNC programers are talented at perfoming those operations manually. I like to think at over 60 years ago I was a respected tool and die machinist. I felt that 55 years ago as we started to use NC machining my experience as a machinist gave me an advantage because I knew that to tell the machine to do. My experience has been those of us programing CNC routers and saws need to have experience using saws and routers manually so has to program CNC machines to do those tasks effectively, efficiently and accurately. I am sure the same is true about sharpening. Bottom line is you must be at one with the edge to make it sharp in such a way it stay sharp. If doing the sharpening manually helps a person be at one with the edge, then that is the best method for that person. And, if manual sharpening is cost effective and the turn-around time is acceptable, then by all means use such a service.

 

[tvgordon]

I agree. Just as in woodworking, the best tools in inexperienced hands are going to yield less than the best results. The first shop I worked in focused on woodcutting tools mainly from hobbyist and construction with a few industrial customers. They sent all the metal working tools to another shop who, in turn, sent all their woodworking tools to them. The second shop was in a larger city and most of their income was from industry. They had automatic grinders for metal cutting blades, welded and sharpened bandsaw blades and had a couple expensive tool and cutter grinders for metal working tools. But, as you said, both shops were owned by older gentlemen who are no longer with us. I know the first shop has closed and I'm not sure about the second. The owners son worked in the shop, but the last time we talked he was questioning if he would be better off working for someone else. Same pay with better insurance while working less hours. Unfortunately it seems the sharpening industry is mirroring many other businesses in that the big get bigger and the small disappear.

Tom

 

[farms100]

place i just started working for has been having  real problems with the sharpeners.

We use a ton of stacked slot cutters and its critical when they get sent out, they are all cutting the exact same diameter and cutting width.

saw blades coming back warped. blades sharpened so many times there is only 1/64 thickness  left of carbide.

 

[tvgordon]

Why not just have then retipped?

Tom

 

[farms100]

Why not just have then retipped?

Tom

thats my thought as well...

 

[jmbfestool]

Not being funny but a Cnc should easily easily be able to sharpen unevenly spaced teeth.    All the Cnc needs is a electrical contact point so the blade rotates round comes in contact with a refrence point through electric current just like current CNC work to refrence 0 from a work piece. 

Pretty sure this is already available for CNC sharpening machines if not somebody bloody make one.   

 

[missionman]

I bring all my blades to Midwest Saw in West Chicago, Il.  He uses CNC and automated blade sharpening systems and has never told me he cannot sharpen a blade due to unevenly spaced teeth.  He sharrpenes everything from circular saw blades to router bits and planer knives.  I have brought him some really banged up and odd blades, but he always get them razor sharp.
Larry

 

[TimCook]

I am an industrial tool sharpener in Texas who uses the same German machines used to manufacture the Festool blades. (actually made by Leitz) Some "cnc" machines are more automated than others. Some are just automatic and advertised as cnc. Variable pitch blades as they are called are designed to offset harmonic vibration and cut quieter and smoother. A true CNC machine has a smart indexing finger that detects the tooth as it indexes and moves each tooth into the exact same position every time so that programmed geometry is accurately reproduced. There are a lot of advantages to CNC sharpening. Take for example a 60 tooth TCG blade. To be properly serviced a 1060 TCG has 180 surfaces that have to be individually ground to within .001 tolerance. Many people consider saw blades a commodity, but if you own Festool, then you obviously can appreciate a quality tool that makes a quality cut.

 

[ccarrolladams]

I am an industrial tool sharpener in Texas who uses the same German machines used to manufacture the Festool blades. (actually made by Leitz) Some "cnc" machines are more automated than others. Some are just automatic and advertised as cnc. Variable pitch blades as they are called are designed to offset harmonic vibration and cut quieter and smoother. A true CNC machine has a smart indexing finger that detects the tooth as it indexes and moves each tooth into the exact same position every time so that programmed geometry is accurately reproduced. There are a lot of advantages to CNC sharpening. Take for example a 60 tooth TCG blade. To be properly serviced a 1060 TCG has 180 surfaces that have to be individually ground to within .001 tolerance. Many people consider saw blades a commodity, but if you own Festool, then you obviously can appreciate a quality tool that makes a quality cut.

[welcome] to The FOG, Tim,

You sound like the professionals at LA Grinding who have been taking care of my metal fabricating tool grinding since 1960 and my woodworking sharpening since 1988. By the time I started buying Festools in 2006, LA Grinding had been sharpening those blades for a couple of years.

So, because most of the sawing done in my shop is not done with TS55s, weeks can go by between one of those fine tooth blades for sharpening. But each week we do sent in several blades for other saws that are equally sophisticated. I have several Kapex and do not use the same type blade on all of them. My frame, door and drawer front department does most of its cross cutting on a dedicated Kapex several hours a day. Most weeks one or two Kapex blades need sharpening.

I am confident the LA Grinding professionals are not competing in their first rodeo when they encounter any of my blades, bits or knives.

This is what relationships is all about.

 

[TimCook]

Thank you for the welcome ccarolladams. There are many good sharpeners around the country who know what they are doing. Unfortunately there are plenty of bad ones too. The tool sharpening industry is self taught. There is no school to attend, no Text books. Everyone starts either by working for someone else who teaches them the trade or learns at the school of hard knocks in the back of their garage with manual equipment. We have to know our industry as well as yours. Just like in manufacturing, tolerance is everything. A blade can be free handed on a bench grinder and be sharp, but will it perform like new? To cut like new and give you the same service life of a new blade, the geometry has to be reproduced precisely like it was manufactured. If one tooth has .020 more carbide removed than the rest of the teeth, it will not touch the material being cut causing the tooth behind it to cut twice the chip load. In some materials this will cause chipping or splintering. The same will happen is a tooth has less material removed in sharpening. It will take a bigger bite causing the same result.
Even for a "good" sharpener with CNC equipment, sometimes a problem blade can slip through the process and not perform. It takes a keen attention to detail and solid quality control process to keep the complaint percentage low. We track our complaints and generally .2% is average. Like I said, it only takes one tooth being out of tolerance to make a bad cut and my shop may grind 50,000 teeth a week that have 150,000 surfaces that each get ground to .001 tolerance. Of course, sharpeners are only as good as the last tool we sharpen. lol
I could talk forever but ill leave you with this. Sharpness is defined by the relationship between the geometry of the cutting edge and the finish that it is ground to. Sharp is a relative term just like quality. I would be happy to answer anyone's questions about sharpening or to refer you to a "good" well respected sharpener in your area. I run a forum for professional sharpeners and know many of my colleagues accross the United States. Have a great day!

 

[greg mann]

The last time I did a rough count we were drilling 120,000 holes per day in ductile iron castings. When I started in this business we used HSS drills and generally sharpened them at a pedestal grinder, by hand. That is unthinkable today. About 8 years ago I had an opportunity to use a drill from a Swiss company that performed exceptionally well on a forged steel steering component, much better than anything I had tried up to that point. Solid carbide coolant fed drills had really begun to make an impact in our industry by that time and the main thing holding them back besides sticker shock was the difficulty in getting them reground. This particular drill, which was working so well for us, had to be abandoned because there was no one I could find domestically that could re-create the like new geometry specific to that drill. I would get them back, they would look beautiful, but they would blow up drilling the first hole! The same drill point geometry that worked so well on a drill from, say Kennametal, would fail dramatically on a different maker's drill, and visa-versa. It has taken the industry the better part of a decade to become reliable in re-grinding solid carbide drills, and generally one needs to make sure the service is well versed in grinding each specific manufacturer's product and all of the permutations within that line, such as geometry for drilling steel versus ductile iron, versus, grey iron, etc. The same holds true for sawblades. A high quality blade can only deliver if it's original design is adhered to religously, or if the service doing the work knows exactly what a deviation from the original configuration will accomplish.   

 

[Peter Durand]

Thank you for the welcome ccarolladams. There are many good sharpeners around the country who know what they are doing. Unfortunately there are plenty of bad ones too. The tool sharpening industry is self taught. There is no school to attend, no Text books. Everyone starts either by working for someone else who teaches them the trade or learns at the school of hard knocks in the back of their garage with manual equipment. We have to know our industry as well as yours. Just like in manufacturing, tolerance is everything. A blade can be free handed on a bench grinder and be sharp, but will it perform like new? To cut like new and give you the same service life of a new blade, the geometry has to be reproduced precisely like it was manufactured. If one tooth has .020 more carbide removed than the rest of the teeth, it will not touch the material being cut causing the tooth behind it to cut twice the chip load. In some materials this will cause chipping or splintering. The same will happen is a tooth has less material removed in sharpening. It will take a bigger bite causing the same result.
Even for a "good" sharpener with CNC equipment, sometimes a problem blade can slip through the process and not perform. It takes a keen attention to detail and solid quality control process to keep the complaint percentage low. We track our complaints and generally .2% is average. Like I said, it only takes one tooth being out of tolerance to make a bad cut and my shop may grind 50,000 teeth a week that have 150,000 surfaces that each get ground to .001 tolerance. Of course, sharpeners are only as good as the last tool we sharpen. lol
I could talk forever but ill leave you with this. Sharpness is defined by the relationship between the geometry of the cutting edge and the finish that it is ground to. Sharp is a relative term just like quality. I would be happy to answer anyone's questions about sharpening or to refer you to a "good" well respected sharpener in your area. I run a forum for professional sharpeners and know many of my colleagues accross the United States. Have a great day!

Thanks for all the information. This is probably a stretch, but would you know anyone in the Vancouver, Canada area you could recommend.

Cheers,

Peter

 

[tiralie]

I run a forum for professional sharpeners and know many of my colleagues accross the United States. Have a great day!

Tim
Thanks for the info.
Tim