Whiplash – Adapting the Drill Bit Sharpening Jig for Another Non-Drill Bit Sharp

[RickKrung]

Just had an interesting experience, with launching into a development project, just to have it pulled away. 

For the past three years, I've been sharpening pruning and clipping tools (scissors, garden clippers, limb loppers) for a local marihuana/hemp grower.  A couple days ago, they brought me their entire arsenal and asked me to sharpened them again, in advance of their harvest processing season (October).  But, this time with a big twist.  They wanted to modify their small nipper/scissors to shorten the blades.  I agreed it was a good idea because the thin, curved blades seemed to dull very quickly due to how they meshed/closed.  Here is what these small nippers look like, 1) stock on the left, 2) parts, including one stock blade and one modified blade, in the middle and 3) shortened blade version on the right. 


The modification involves cutting the blade shorter and grinding the spine profile.  Based on the example presented by the grower, I used three facets.  Initially, I did freehand, but knew I needed to develop a jig in order to have some consistency and efficiency.  I thought the Drill Bit Jig, with the vertical and rotational angle positioning, and adjustable feed stop platform was the perfect place to start. 


I also wanted a manner of holding the nipper blades for fast interchange as there are 30 pairs to modify and sharpen (60 individual blades).



I designed and made a flat plate platform, with a sloped groove on the bottom to follow the guide on the DBS platform and a tab for positioning with the adjustable feed stop.  To hold and position the nipper blades, I used dowel pins. 



Have to stop here as there too many photos for a single post. 

Rick

[RickKrung]

Continuation

Top side pins. 


Bottom side grooves.


Blade in tip grinding position.


Blade in spine grinding position.  Two angles are used in this position to achieve the second and third facets. 


Here it is in use with an 80 grit CBN wheel on an 8" slow speed Rikon grinder.


It took about a day to design and make the scissor blade platform and test it out on a couple sets of nippers.  I had given the growers my initial freehand version to test.  I did not expect the call I got tonight, letting me know the shortened nipper blades do not work as hoped (I assumed they had previously tried out their own first versions that they modified with an angle grinder and presented to me as examples).  The shortened blades lack enough length to capture and close on the hemp plant stems.  They have called off further work on shortening the nippers and asked to just have them sharpened.  That is the whiplash. 

No matter, though, as the flat plate, blade holding jig made for this project looks to be an excellent platform for other potential non-drill bit sharpening uses of the Tormek Drill Bit Sharpening Jig, the DBS-22.  I do not actually mind not having to modify those 60 blades, even though there will substantially less CBD oil as compensation. 

Onward,

Rick

PS. I posted this in the general forum, as it is more about adapting existing tools/jigs for new purposes than it is about either scissor sharpening or drill bits. 

[micha]

Rick,

kudos to the man behind the mill! What a sophisticated approach!

I can imagine quite some applications for having a horizontally movable pivot point, with the vertical fine adjustment of the DBS plate. And the dowel plugs will allow for great flexibilty.

Great idea, thanks for sharing.

Mike

[tgbto]

That is one awesome modification, AND I like the looks of the facets on the blade !

Is the wear of a CBN wheel just close to none for that kind of use ? Or did you manage to cut the blades close enough to the final shape that you really are not removing so much material ?

[RickKrung]

Thanks, guys.  I don't know what that platform might be useful for in the future, but I'm glad I have it for when the next situation arises. 

The dowel pins were specific for this blade mod application, but there is plenty of real estate for threaded mounting holes and the like for whatever else may be needed.  The trick was milling the sloped groove, which was actually not as difficult as I thought.  The sides are 20º and I clamped the plate on a set of angle templates that I got from my brother's tools, that came out of my father's machine shop after it closed.  Clamping the plate to the angle template/vise was the biggest challenge there. 


I do not know how much CBN wheels wear, but my assumption is, as with diamond wheels, none or so nil as to be none.  This was my first use of either of the two CBN wheels I got from Woodturners Wonders last spring.  The other is a 10", 180 grit for the T8.  The grind finish of the 80 grit on the Rikon is quite coarse and had I envisioned running the blades on the T8 with the CBN and/or diamond wheels to refine the grind finish.  But, given the numbers and production atmosphere of this project, it is likely I'd have just gone with the 80 grit.  On a one or a few off project, I'd refine it more, similar to what I do with drill bits. 

I tried to cut the blades close to finish length to minimize the amount of grinding, but being careful to not cut them too short.   As stated above, I wanted to use the platform as a jig on the mini cutoff saw but the blades haven't arrived yet. 


I set the platform up, clamped to the table, under the T8 USB and used my laser "LOC" indicator as a guide for using a Dremel cut off wheel.  It worked, but was still a bit variable. 




There was still a fair bit of grinding to be done for the two facets on the spine, however.  The 80 grit wheel on the Rikon made quick work of that.  I was being careful not to use too much pressure, also, partly so as not to damage the CBN and partly to control heat build up in the blades.  The latter was not much trouble. 

Rick

[RichColvin]

Nicely done, Rick!

[Ken S]

Bravo, Rick!

Another fine example from you of what a clever user can do with a Tormek!

Keep up the good work!

Ken

[BeSharp]

I'm impressed ... as always with your skill!

[RickKrung]

Thanks once again for the comments and compliments.

Now for the reverse whiplash.  The growers worked with the initial shortened clippers on stems more like what they will be during harvest and cleaning.  Also, I tweeked the mod a little to retain a bit more of the length and provided the growers with these to try out.  I am using the 180 grit CBN for the blade sharpening operation, reasoning that a "toothy" finish may be advantageous.  They have decided the shortened clippers ARE working well and to go ahead with the shortening mods on the rest of the clippers.  I plan on making a couple more trial versions, with slightly longer blades, yet, and provide them to the growers for testing. 

I am going to wait for the abrasive cutoff blades to arrive (Monday) from MicroMark before embarking on any more blade cutting.  I'm right in the middle (packing up room contents into moving boxes) of helping my daughter's move back to Portland, OR.  I'll be picking up a trailer Monday, loading and hopefully driving it on Tues. (or Weds.).  So I won't get back to this a few days.  And then there will be another moving/trailer run the following week.  Fortunately, the growers have given me some good lead time.  I just hope I can squeeze it all in before October. 

Rick