Crisp grind lines on shallow angles?

Joss

Joss

Joined
Nov 20, 2001
Messages
7,353
Hi,

How doi you guys keep the grind lines crisp, especially when the angle is shallow? For example, the central ridge on a dagger is fairly shallow (typically) - how do you keep it crisep, esp during the polishing process?

Thanks,

JD
 
I'm no master of knife polishing by any stretch but here's a suggestion...

When polishing, grinding, et cetera, you don't necessarily want polishing surfaces to "give" much and form to the surface of the blade. If you're polishing with paper, use a very hard block such as a piece of glass or ceramic for backing. The idea is to keep the paper from rolling over the edge or the spine accidentally while polishing. I guess I would also side with the suggestion that practice makes perfect. By no means is my suggestion a) the only one or b) foolproof.

Setting lines to be nice and crisp can take a lot of work, so don't get frustrated and try to polish really hard or really fast.

I'm sure there are better suggestions, but I'll offer it for consideration anyway.
 
Nathan and Robert have given you golden advice.

As an example, I am fortunate enough to have 2 fighter blades that were ground from 1095 given to me by Michael Cooper (L6STEEL). They were hollow ground, and I didn't have a rounded surface to match the hollows, so I've been using a strip of leather to do the job. Now I am very busy, so I have only been able to work on the projects here and there, and I've been doing this for MANY months now. At first, I ruined the lines because my sanding gear wasn't hard. But as time has gone by, I have elarned to control the strip of leather, and I've actually been able to adjust the grind lines to where I want them.

So, to reiterate what Nathan and Robert said, if you want crisp lines, get yourself hard sanding blocks. And just keep on sanding/grinding away. It takes several blades before you get perfect results! If you don't have good gear (like me and my strip of leather!), you still can get good results. Just realize that it may take more time to figure out how to get the most out of your gear. However, there are limits as to what you can do with less-than-proper tools.
 
On hand rubbbing a blade and keeping the line crisp.I have a little
thing I made up.I had a hard rubber wheel,you can get them from plumbing stores,I cut a half rounded pieace and glue it to a strip a metal strip.I then cut sanding paper into srtip and put them on my little hand rubber jig,I then take the sand paper on the rounded
sruface were teh hollow is.for my flats I have a pieace of micarta
with leather glued to then put a piece og sanded paer on it and go to town.I will get some pix for you to see.:)
 
Hi,

Well, I do the stock removal with files, so hollow grind is not really an option at that stage. I use paper in the early stage after filing, but then I switch to stones. With stones, would you focus on polishing legthwise just under the ridge with the coarsest stone (120)?

BTW, stones are the way to go in small areas, or curved, etc. They are amazingly easy to use - much easier than paper, and less messy.

For those interested, I use EDM Red Brick stones that were recommended by Don Fogg. If you go to www.mscdirect.com, the product codes are (for a given size):
220 grit - 05117221
320 grit - 05117239
600 grit - 05117254
 
Hey Joss-

What I do is stay away from the centerline while sanding.

I use a micarta block to get close to the finish I want, and then make the final passes with a hardwood block with leather on it.

You only want to make the last passes with anything other than a hard block or stone, as it will readily "round over" your line.

Something no one mentioned is making sure your blade is secure. That's why I built that sanding fixture I showed you. Especially with a distal taper in a blade, you can have a lot of "flex" sanding from ricasso to tip if you don't have the blade locked down tight.

Let me know how it goes!
Nick
 
NickWheeler said:
Hey Joss-

What I do is stay away from the centerline while sanding.

I use a micarta block to get close to the finish I want, and then make the final passes with a hardwood block with leather on it.

You only want to make the last passes with anything other than a hard block or stone, as it will readily "round over" your line.

Something no one mentioned is making sure your blade is secure. That's why I built that sanding fixture I showed you. Especially with a distal taper in a blade, you can have a lot of "flex" sanding from ricasso to tip if you don't have the blade locked down tight.

Let me know how it goes!
Nick
Click to expand...
Nick, what do you use for the last step with hollow grinds. (great flat hand sand video you made. thanks).
 
NickWheeler said:
Something no one mentioned is making sure your blade is secure. That's why I built that sanding fixture I showed you. Especially with a distal taper in a blade, you can have a lot of "flex" sanding from ricasso to tip if you don't have the blade locked down tight.
Nick
Click to expand...

The replica I made of your sanding jig works great! Thanks for sharing.
 
It's not really that a hollow ground blade gives a crisper grind line, the angle between the grind line and bevel surface is just greater making it appear more pronounced than a similar grind line on a flat ground blade. Its easier to wipe out the grind lines on a flat ground blade than it is a hollow ground blade, for the same reason.

Ending up with crisp grind lines, whether on a flat or hollow ground blade, is accomplished by maintaining the correct abrasive surface pitch along a longitudinal spiral while navigating a second spiral along the opposite plane; if the blade was ground with distal taper. Now thats some tricky hand control. It takes practice however its accomplished.

Fred
 
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