jigs... not for the purist of purists.

RangerBobTX said:
I disagree. All the jigs that allow grinding of both sides have two inherent problems; the blade is cantilevered out away from the base which creates the opportunity to have the friction of the belt pull the blade downward and if the knife is not mounted absolutely plumb to the base, the grind angles will not be equal. This jig may not be faster but, I think it is going to be harder to make a mistake using it.

Bob
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this is how clare fixed the issue with the blade moving or being pulled out of place. it has a 1/8 "shelf" milled into the front of the jig for the spine of the blade to rest on, preventing the blade from being pulled down at all. I have never had a blade move when the C-clamps are on even lightly.

the adjustment is done by fine threaded bolt that pushes against the base. Since the base is secured firmly with a huge spring with no play it makes for little to no play at all. the only thing that allows any flex at all is the springs and if I am pushing that hard, I am likely putting way too much pressure on the blade. I'm not saying it is the perfect jig, but with it I have managed to crank out knives with accuracy and repeatability that I couldn't match otherwise.
 
Just finished a bevel grinding jig... simple design... my platen angle is adjustable, so why bother with a fancy setup to adjust the angle of the blade?

Case hardened the components... not perfect, but should extend the life a bit from wear against the side of the belt. I'll look for tool steel to do the next version.

Just ordered an angle cube which makes it much easier to check that it's perfectly square, and to adjust the platen angle.

North American Tools has a Tap Hole Calculator app for the iPhone... tap calculator is crap (I use an app called Drill Tap Tool which is way cool) but the NAT app also has a neat trigonometry calculator that's perfect for calculating bevel angles.

The photos show the jig with a parallel plate set up when I was grinding the base to get it square. Tested it out on a blank before I had it finally squared up, and while the bevels obviously weren't even, the grind was very easy to keep flat and the plunge line was nice and clean.

Back to the grind... no excuses now!







 
Gee guys you are making it sooo complicated. I think you better get one like Aaron is getting into service. A tilting table and a sled is all that is needed to do even recurve blades and remember if you can't control how the blade moves how will you ever get different results as needed.
Frank
 
Who made that jig and how could I get a hold of him? I am real interested.

Lo/Rez said:
I made this one when I first started making knives.

Ghettojig_zpsbc1fccbe.jpg


I got this one from the guy who made my grinder.

AwesomeJig_zpscf2613dc.jpg


Filingjig_zps09fdf116.jpg


Grindingjig1_zps7446365f.jpg
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Jk9WpEJ3ygnLU_KtHcwquldetKjgAXGjUVUoUc3LsPc=w473-h480-no


Used to grind bevels, false edges, sharpening, grinding distal taper, surface grinding and it weights 3 oz. :)
 
Frank Niro said:
Gee guys you are making it sooo complicated. I think you better get one like Aaron is getting into service. A tilting table and a sled is all that is needed to do even recurve blades and remember if you can't control how the blade moves how will you ever get different results as needed.
Frank
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I don't see it as complicated Frank... quite the opposite for me. It's just a simple jig that clamps to the blade and holds it at a given angle and allows me to hold that angle and make minute changes with the simple twist of one knob. If you had to make the jig, it would be like more prep work upfront for an easier time in the long run, like the machinist setting up his whatever thingys he sets up to make things. This saves me a lot of time and reduces my hand sanding time by a lot and therefore makes my knife making experience easier and makes things simpler.
 
Fred.Rowe said:
Jk9WpEJ3ygnLU_KtHcwquldetKjgAXGjUVUoUc3LsPc=w473-h480-no


Used to grind bevels, false edges, sharpening, grinding distal taper, surface grinding and it weights 3 oz. :)
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correct me if I'm wrong fred but isn't the bubble jig still used for freehand grinding? This means it doesn't mechanically hold the blade in a fixed position right?
 
rustyrazor said:
correct me if I'm wrong fred but isn't the bubble jig still used for freehand grinding? This means it doesn't mechanically hold the blade in a fixed position right?
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"In metalworking, a jig is a type of custom-made tool used to control the location and/or motion of another tool. A jig's primary purpose is to provide repeatability, accuracy, and interchangeability in the manufacturing of products. A jig is often confused with a fixture; a fixture holds the work in a fixed location."

Technically, the bubble jig is only an angle indicator.
 
The name is a misnomer, for clarity it should be called the Bubble Sight Reference. We've ground with some form of this tool, in our shop, for years. Some one ask what it was called and I answered Bubble Jig for lack of any thing better, it stuck.

Fred
 
In truth I believe if it works for you then it's the right one for you to use !
Frank
 
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Frank Niro said:
In truth I believe if it works for you then it's the right one for use to use !
Frank
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Amen.

Personally I'm not a jig guy. Tried em, even built a nearly hands free linear bearing setup, but ended up ditching em. I feel like jigs slow down the process and since I have ADD (seriously, and most of you guys know so) I will doddle off to work on something else before I ever get the thing set in the jig. I think i do pretty good flats freehand...
88cdb342745de9477a05fbf3fe5040a7.jpg

Effed up a lot of steel learning, but just like the feel of nothing between me and screwing the whole pooch but good.

But, if you do well with a jig, and it produces the results you were looking for, then good on ya. Heck, One outfit is actively selling knives that still have tooling marks in the blade 'bevels.' And that is the extreme end of this discussion... Letting the tool do 100% of the physical work.

But hey, this is my one hippy area. Making knives. If it feels good, do it! Anyone who takes the plunge and starts with nothing, and ends up with at least a KSO at the end is just aces in my book, regardless how they get there.


Cheers!
-Eric
 
Fred.Rowe said:
The name is a misnomer, for clarity it should be called the Bubble Sight Reference. We've ground with some form of this tool, in our shop, for years. Some one ask what it was called and I answered Bubble Jig for lack of any thing better, it stuck.

Fred
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lol... and apparently this whole thread is a misnomer. I should have called it "fixtures... not for purists" but that's just one more thing I don't get right... of the many. I'm about to go out and make a few more mistakes in the shop right now.. likely with my ole "fixture" :D
 
One of the things jigs/fixtures are good for is helping newer makers understand the angle that bevels need to be. After a while of grinding with a jig/fixture you are able to tell exactly how the knife needs to be engaging the belt to get a desired angle. I started out grinding freehand and was horrible at it. I switch to using a jig/fixture and got my grinds even and clean. Then, when I switched back to freehand, my grinds were a world better than before.

When I started back up with freehand grinding I used the tool rest a good amount. If you rest/slide the spine across it while pulling the blade across the belt it helps a lot. This video helped me a ton with getting back into grinding without a jig/fixture.

https://www.youtube.com/watch?v=MAgD3bvsY1o
 
rmbonham said:
Who made that jig and how could I get a hold of him? I am real interested.
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I made the first one (on the 1x36). The guy who built my grinder made the second one. You could Google Sahtu Designs and it should bring up a link to his website.
 
Lo/Rez said:
I made the first one (on the 1x36). The guy who built my grinder made the second one. You could Google Sahtu Designs and it should bring up a link to his website.
Click to expand...

Thank you. I free grind but I am also a huge fan of jigs and own numerous ones for many different aspects of knife making. I am always on the look out for new jigs that are either better than my current jigs or help with a whole different thing altogether.
 
JG Custom Metal Works said:
One of the things jigs/fixtures are good for is helping newer makers understand the angle that bevels need to be. After a while of grinding with a jig/fixture you are able to tell exactly how the knife needs to be engaging the belt to get a desired angle. I started out grinding freehand and was horrible at it. I switch to using a jig/fixture and got my grinds even and clean. Then, when I switched back to freehand, my grinds were a world better than before.

When I started back up with freehand grinding I used the tool rest a good amount. If you rest/slide the spine across it while pulling the blade across the belt it helps a lot. This video helped me a ton with getting back into grinding without a jig/fixture.

https://www.youtube.com/watch?v=MAgD3bvsY1o
Click to expand...

I am still on the beginning of that learning curve, but I think you're probably spot on... using the jig, I am sensing that I am more consciously aware of the angles involved. There's no getting around the fact that repetition is the only way to build competence.

Those video links you posted were excellent... it has also given me a new appreciation for the role of my disk grinder! I plan to add a forward/reverse switch so I can try some of those techniques!

It's a good day when I learn something new!!!
 
Yep, that's on the project list as well... it currently runs off the 4 step pulley shaft on my grinder on a 1,750RPM motor, so I have a little control... a second grinder build with VFD is on the list back there somewhere down the road.
 
Talking about jigs do any of you have my "one legged man" to do the end of the leaf spring for a liner lock. Sorry I don't do pictures, but maybe one of the makers I've helped with liner locks will post one.
Frank
 
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