What’s the deal with the 800 mm radius on Japanese Shears?

The 800 mm radius myth started a number of years ago. Larry Brooks, a well respected retired shear sharpener, wrote a book on how to sharpen beauty scissors. To my knowledge this is still the only book on how to sharpen beauty shears. I bought it and read it and found it had a lot of good information Larry noticed that shears from Japan have a curvature to the edge of the blade, a belly so to speak. He wanted to know what the curvature was and took several of the shears he had at that time and laid them on his barn floor and drew a circle from the shape of the edge of the blade. Lo and behold, all the shears he had an 800 mm radius. This piece of information was interesting but accurate for only the shears he picked up and measured. It is not accurate for all shears.

The best radius for a shear for the least push and the best cut is 800 mm. HOWEVER, just like there are specific paint brushes for specific purposes for painting there are different edges of shears that make them specifically better for slide cutting, point cutting, blunt cutting, texturizing and more. These will all have a different radius to make them more suitable for a particular purpose.




When sharpening, the sharpener should when possible maintain or reestablish the original radius. Sometimes due to damage to shear from previous sharpening, deep nicks or other issues it is not in the best interest of the longevity of the edge to restore the original radius. All of this means
that the sharpener and his or her equipment must be able to follow the edge of the blade and can create any radius that is on the market and be prepared for the shears of the future.

The Bonika Firefly Shear has a different radius on each of the blades. The top blade has a radius of approximately 1200 mm (almost straight) and the lower blade has a low radius of around 600 mm (curved). In addition, the edge angle of the two blades are different as well. This shear is one
example why a 800 mm radius would be inappropriate for this shear. Other shears like the
Bonika Fishbone has a low radius to slide cut and point cut better while most German type shears like the Kretzer have a high radius for straight line precise cutting.


For those who want to know more from the manufacturer’s point of view this is a video clip from a sharpening convention in which a USA scissor manufacturer answers to question of a sharpening concerning the 800 mm radius.
https://youtu.be/bmvMe6SfKco


If you are looking for sharpening equipment please be sure you purchase equipment like the
Scimech Scissor Flathone and others that can address all the different radii found on today’s shears from a 500mm to 1500mm as well as the 800mm. If you have equipment that will only sharpen a 800 mm radius my suggestion is to purchase another clamping system so that you have the flexibility to sharpen any type of shear or scissor on the market today and will appear on the market tomorrow.

Reaction to ON THE EDGE article by Bonnie Megowan

THE QUESTION:

Date: Sun, 7 Jul 2013 13:00:40 -0400
Subject: On The Edge Article
From: sharpshop39@gmail.com
To: bonikashears@live.com

Bonnie - I just read your articled "One Click Difference" in Jim O'Donnell's news letter and I have to differ with you on a couple of your statements.  I really did like that there is now a way of testing/proving/measuring the amount of pressure needed to cut through different material(s).  I'm sure that it was quite interesting.

But, my difference with your article concerns the setting of the 'blade tension' between the two blades (1st paragraph).  I was instructed at WOLFF Inc., by Tom, that the blades on grooming shears, 1) should NEVER clang together when drop tested and 2) should stop approximately 1/2 to 3/4 inch before tips close completely.  I was also instructed that this tensioning is indeed different for the various applications, i.e., barber, beautician, groomer, stylist, etc.  Everything that I was ever shown/taught is directly opposite to what you have in your article.  Now, I know that I am only a novice in this business to most everybody else and I primarily only do groomers (Dog Shows & Horse Shows), with a few beauticians locally thrown in. But, now I have questions?  If the shears tension is to be tight enough that the shears don't move when drop tested, won't that lead to faster wearing/dulling of the edges?  If excess tension is placed on the edges in a drop test, what about the pressure/tension that a groomer puts on those edges when they close the shears?  This is particularly important when using convex shears, which most professional handlers, show groomers, etc., use.  Additionally, it also exerts additional pressure on the groomers, stylist, barbers, beauticians wrist further inflaming the nerves (Corpal Tunnel Syndrome)?

I have always taught/instructed my customers that I have set their shears tension to the standard (drop test) and they they have the choice to have that setting adjusted to their preference.  All Beauticians, Stylists that I have worked with wanted that tension "lessened" so that the shears almost 'clanged' when drop tested.  Their comment's are that they don't want any blade tension wearing out their wrists because of the amount of time they use the shears (exhaustive).  The animal groomers are also pretty close on that issue also, but not to the point that the Beauticians require.

So, you can see my confusion.  Guess that I will just have to continue in the methods that I have developed so as to continue satisfying the preponderance of my customers.

Thanks for your time

Gil Settlage

GIL'S SHARP SHOP

My Answer

Hello Gil,

I totally agree with you.  I was taught exactly like you for the same reasons. Then I trained with Casper Kiser with Eickert who made groomer and beauty shears. He said if a shear was in proper alignment (and most groomer shears are not) IF they were made well and properly aligned they should be one "click" TIGHTER than the movement. In other words they should not drop at all and be one click from dropping. This seemed totally wrong, but he had decades of experience with this. I talked to other manufacturers and they loosened the shears slightly, but did not fall below the half way mark. So I was in the same place as you. This equipment allowed me to test my hypothesis like a scientist and this was the results based on the particular well aligned, brand new, sharp shear I was using. The tension that used the least effort was when the blade just began to drop. The looser tension used more effort on the part of the user.

Would this work on a used dog grooming shear that was slightly out of alignment? there are other questions. However, I would rather err on the side of too tight than too loose since shears tend to loosen up.

What makes sharpening interesting is the new growth of knowledge. Although Casper was not at the sharpening convention, I think even he would rethink his ideas on tension. He was most likely taught by Uwe who is a mechanical engineer. I'm not sure where he learned. That would be a great question for him and a discussion for SharpNet.

The bottom line to me is the customer is the expert. If they think the shears cut best for them with them clanking shut or so tight you need pliers to close them we as their mechanics must make the shears work for them in the way they want to use them. If they do not express a preference, we must adjust them based on our knowledge of what would be best for the shears and the client.

Bonnie

Bonnie Megowan and Mystie Hunter

Scissor Mechanic, LLC d/b/a 

Bonika Shears

2385 Clower St Ste C, Snellville, GA 30078770-972-4332   Fax 770-972-4330                                                  Get our newsletter

 

Announcing the 14th Annual Sharpeners Jam

July 23-25, 2011, Atlanta

Largest International Convention and Meeting of Scissor Sharpeners in the USA. Free event for sharpeners from all over the world to share their ideas. There is no charge to attend our two day meetings. However, there are charges for additional classes and entertainment. (see below)Location: Country Inn and Suites, Duluth, GA (just northeast of Atlanta)

FREE EVENTS

Saturday Night Meet and Greet in the Vendors Rooms Sunday Sharpeners Jam Session All sharpeners will share at least one idea that has helped their business. Caregories include sales, marketing, sharpening innovations, organization, increased efficiencies and more. Be prepared to share with the others. Vote for the best ideas. Prizes and awards for the top ideas! This is an all day event proceeded by a short Sunday Morning time of Praise and Worship. Read the ideas from last year's Jam

Monday Topical Speakers

Casper Kiser - T.E.A. Time with Casper (How to keep yourself out of hot water in sharpening by understanding the tension, edge and alignment of scissors) Casper Kiser is the floor plant manager of Oster Products, Jarden Industries in McMinnville, TN.

Harrelson Stanley – Modern Abrasive Technology Modern Japanese alloys present many challenges to today’s sharpener. Learn about hone line and edge creation on shears using Shapton’s technical approach and demonstrating live with a digital microscope. Harrelson is the president of HBS Enterprise, the master importer of Shapton for North America.

Jim O’Donnell – Making Money with Industrial Shears. Enlarge your income base by expanding your sharpening. Jim is the publisher at On The Edge Newsletter and is VP Marketing at Wolff Industries.

Workshops

• TLC Sharpening: How to Sharpen Texturizers, Leftys and Curves Learn from Casper Kiser
  
• Clipper Blade Sharpening Bob Schiessl from Nebraska Blades
  
• Clipper Repair Jason Sturm from EdgePro
  
• Knife Sharpening on a FlatHone Jason Sturm
  
• Equipment Tune-up with Frank Davis of Davis Sharpening
  
• Flathone Shear Sharpening Classes taught by Bonnie Megowan

Food and Entertainment



• Qzar Laser Tag
  
• Light lunch on Sunday, Monday and Tuesday
  
• Group Dinner at a Local Restaurant Vendors The vendors will be available for your shopping pleasure during break times and before and after sessions throughout the week-end. Bonika bargain room will be set up and complete sharpening supplies and equipment from Bonika along with Bonika Shears. Other vendors include Nebraska Blades, EdgePro, Kenchii Shears, Kretzer Scissors, Hanako Shears, Lucky Hare Shears, Kudzu, Belson, Conair, Shapton Stones and more. See the website for the most updated list. There are some super JAM ONLY deals, so come prepared to shop.

First 30 who register get a their chocie of one of 5 Marketing DVD's

• Ron Ellis
  
• Ed Wozniak
  
• Doug Clark
  
• Gene Megowan or
  
• Chuck Bigelow

Certificates of completion included in all paid events.

Register and see details at http://www.sharpenersjam.com/

Testimonial about the Sharpening DVD's

Hi Bonnie
Thank you for making the 6 cd set on sharpening with Casper Kiser. I was not sure what to expect but I found them professionally done and I have learnt a lot. As a result I will start to change some "bad" sharpening habits I have developed. I received the CD's late yesterday afternoon and have been glued to them ever since, the 5 hours went by quickly making me want more. There is not much available for me in the way of learning material here so I do appreciate the information you make available. I am positive this will help me grow my business. I know very little about alignment I am always interested in any information available.
Stan

If you are a sharpener and are interested in some of our sharpening DVD's please contact us.

Casper Kiser Sharpening DVD's

We have the complete educational presentations in DVD format by Casper Kiser from the Sharpener's Jam this year. Casper is the plant floor supervisor from Oster / Arius Eickert and is the foremost expert on shears and sharpening in the USA. We now have 5 hours of DVD education that is useful no matter what sharpening system you have. Learn how shears are made and understand the twist in the Hollow and the Hone, see a demonstration of shears realigning without bending or hammering in Casper Kiser's Advanced Shear Sharpening. Then sit with the audience and here questions asked and answered by the expert in the Q & A with Casper DVD. Order from Bonika shears website or the wholesale website http://www.beautystoreworld.com/

Excerpt from the Hollow and the Honelecture by Casper Kiser Oster / Eickertat the 2010 Sharpeners Jam

Click screen to play short 8 minute video.

Excerpt from our new 2 part DVD. This is the most complete video presentation of the complexities of shear manufacture and function made to date. This 2 DVD set, each part 50 minutes will explore with clear illustrations the
honed and non-honed shears and how and why they are made and sharpened differently
the "twist" in shears, what it is and what it isn't
the importance of the hollow grind and how it affects the performance of shears
what correct and in-correct honing looks like and how it affects the cut
angle selection, the pros and cons of sharp vs strong edges
how and why shears are put back into correct alignment
and much, much more.This is one of those videos you will watch over and over and learn something new each time. This is an essential part of every scissor sharpeners library. You will have a new appreciation for the complexity of the beauty and groomer shears.Casper Kiser is the plant floor supervisor in McMinnville, TN for the Oster factory. He has had over 15 years experience in the manufacture of beauty and groomer shears with the Arius Eickert company. This lecture was presented to sharpeners at the 2010 Sharpeners Jam in Atlanta, GA. Here their questions and comments as Casper clearly shares with a small select group of sharpeners his years of experience. Call 1-888-290-3393 to order this DVD set or order from our website http://www.beautystoreworld.net/vhh.html (Use ID: sharpener Password: Guest)

2 New Jam DVD's ready!

The 60 minute DVD of the best ideas from the 2010 Sharpeners Jam is now ready. Price is $15.00. Also we have a new marketing DVD with Denise Russell from Belson available for $10.00. It is free with any wholesale Belson purchase. Let us know if you are interested in these DVD's/ I'm working on editing the Hollow and the Hone with Casper Kiser of Arius Eickert / Oster which should be out in the next week.

Born in the USA

Some things are still made in America. We saw that first hand when we were granted a tour of the Oster Plant in McMinnville, TN. The logistics were worked out in the spring through Casper Kiser, the plant superintendent of Oster. Gene and I have known Casper since 1997 when he was with Arius Eickert in Fremont, OH. We were delighted when we heard he was in charge of the shear production at the Oster plant facility. Frank Davis, Ed Wozniak and our Bonika staff, Harry, Jay, Mystie, Gene and I along with a handful wives were able to see the entire facility. This was made even more exciting since tours are rare and we had never seen photos of their operation since photography and videography are strictly forbidden.

What did we see? We saw skilled, efficient friendly Tennesseans each with decades of experience making shears and clippers. Stanley Gross, the business team leader of the blades department proudly gave us a tour of the clipper production area. The facility was enormous and all the Oster clippers are made right there with the exception of the screws and some of the newer small trimmers. The housing and parts were created from raw materials to the final product. We watched heat treat process and cryogenic freezing process of the clipper blades and individually hand sharpened, assembled and tested. Modern machines wound copper wire for the motors and lasers etched the name on each blade.

What did we learn? The comb or upper blade of the Oster clipper is ground flat and the lower blade or cutter is ground hollow at an incline angle on the plate that is a proprietary secret. We also learned innovations are coming based on feedback from the customers and clipper repair folks.

We ended our tour in the area of my interest, shears. Since Oster purchased Arius Eickert a few years back the scissor factory there went through a lot of changes and innovations since they were in Ohio. Now, only the finishing operation, the part that makes the shears cut is made in the factory. We were told the shears are coming in semi-finished from Asia (none from Pakistan). In other words, the 440C shears come with handles attached and polished before they reach the states. The hone, hollow and finishing is completed there in Tennessee. That means the part that actually does the cutting is in fact made in the US.

Although we were not allowed to see the actual clamping mechanism we had a general demonstration on how the hollow is put in the inside of the blade and how the so called “twist” is formed. I was impressed with the small size of the wheel (about 3” diameter), which is much smaller than those I’ve seen in other factories. The deeper hollow makes the ride or hone line easier to create and for us sharpeners to maintain. The initial convex shape was created free hand on a large flathone and the final edge precisely ground using a modified clamp on three smaller 6” stone flathones using progressively finer and finer grit. Final alignment tweaking was done with a brass bending block rather than hammers. Between each step of the operation, an inspector tests every shear before in proceeds to the next step on the production line.

Our observation of the shear making process impressed on us the importance of the hollow and the hone as well the skills and abilities of the scissor workers. Casper will be giving a more in-depth understanding of the process when he speaks at the Sharpeners Jam the last week-end of July in Atlanta.