grinding a tight inside curve?

[insanity]

Ok so how do you folks do it? Preferably a flat grind. My best thought so far is that the corner of the platten might work, but I haven't tried it yet.

Wayne

 

[butcher_block]

dont know if this helps but i cut a pipe in about half and welded it to a bit of angle iron i use this as the platten on flat grinds
im working with a 1x42 grinder and the same platten works well for finger grooves using a soft belt sorta like having a small wheel standing on end i can post a picture if you would like

 

[Mark Williams]

Sometimes going back to basics is best. I use files and sandpaper wrapped around dowels.

Trackrock? Sept 24th

 

[Kim Breed]

You can also come at the wheel 90 degrees at the bottom. depending on tightness of inside curve. if all else fails use a half bastard file and hand sanding. good luck.

 

[Terry_Dodson]

Butcher-block, i would like to see a picture.

 

[STR]

In the old days I did it by hand with a dremmel and one of the flints off of an old lighter. These are pure carbide and fit a handpiece screw shank just fine so I just used them for course removal.

Now I use something more like a small silicon carbide wheel in real tight spots like to form the choil on my folders where the blade folds down nicely over the stop pin when closed. I still do it by hand with my Foredom handpiece but I don't have to break apart old lighters anymore since I started buying the small dental wheels I use.

 

[butcher_block]

Butcher-block, i would like to see a picture.

as they say something about wishing and commanding

 

[Terry_Dodson]

ahhhhhh i see, you made a rounded Platen

 

[butcher_block]

yep next one i do will have less curve and by then the delta will will be just for handles i nee to get a 2x72 soon btw it helps to use a hi flex belt i like the 3m trizact stuff
i have used 36 grit stuff it just doesnt wrap around the platen well

 

[insanity]

I like the rounded platten. What I meant to ask about was grinding the bevel on a blade that is a sharp inside curve, like a claw form.

Mark I don't think I'll be able to make it to Trackrock this year. grrr stupid job.

Wayne

 

[David Wesner]

Insanity I think I know what you're trying to acomplish.Not being experienced at this type of grind I would attack it by grinding the flat grind inside radius parallel to the face of a contact wheel rather than grinding perpendicular to the contact wheel such as in a "Hollow Grind" technique.I would think that a smaller diameter contact wheel than is typically used in a Hollow grind i.e. 8-14" dia. would be better to use as long as you didn't dwell & create a scallop effect. I use a 10" dia. wheel for my hollow grinding and adjust the grind height by using "Bimjo's Grind Height Widget" Based on the calculations of Rob Frink of BEAUMONT METALWORKS http://bimjo.com/free/widget.html and think that the larger dia. wheel might not work as well in a tight inside rad.,but I'm not sure about that statement,I would have to experiment a little like you I'm sure will too.Thats how I think I would try it.Good luck .

 

[butcher_block]

well i guess i was not thinking about the ame type of grind please let me see what your talking about

 

[David Wesner]

Hey ButcherBlk,I think insanity wants to know how a Blade style similar to "Witch Claw" by "Blinker" on pg.2 of the fixed blade for sale folder,was ground......I think.... am I correct insanity?

 

[insanity]

The witch claw would be fairly close, but the knife is smaller o/a with a tighter curve to the blade, and for added fun I want to have plunge cuts and a ricasso area.

WS