How to polish blind hole (divot) bevel?

eyeeatingfish

eyeeatingfish

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Dec 9, 2003
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I have been wondering how to get a nice finish on a bevel on a blade. On an exposed hole I use a countersink to create the bevel sometimes so it isn't sharp. The I also use a beveled hole as a place for a kydex sheath to index on.
I have been trying to figure out if there is any special bit or technique to polish the hole for a high quality finish. When I use a damascus blade I think polishing the hole bevel is really going to show extra quality and the layers of the steel. I don't think any Dremel stone bits are going to be smooth enough to give a good polish. Anyone have any secrets?
 
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All the above will work, but won't necessarily polish the edges evenly.
Lapping the entire surface with a wooden cone will smooth out every scratch and polish it as high as you wish to go. It is also really fast.

Here is a simple sketch of what I am talking about. Just thin the end of the dowel to fit the hole and apply some grinding compound to the lip. It will shape to the hole bevel and smooth everything nicely.
 

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Stacy E. Apelt - Bladesmith said:
All the above will work, but won't necessarily polish the edges evenly.
Lapping the entire surface with a wooden cone will smooth out every scratch and polish it as high as you wish to go. It is also really fast.

Here is a simple sketch of what I am talking about. Just thin the end of the dowel to fit the hole and apply some grinding compound to the lip. It will shape to the hole bevel and smooth everything nicely.
Click to expand...
Thanks for the tips. I thought about using a wooden dowel and trying to attach sandpaper but the polish sounds much easier! I do have cone shaped felt polishing tips for the dremel but I am guessing I might want something a bit harder? Those Dedeco tips look useful too, sometimes I need to polish really small radiuses on my blades, but holy crap they are expensive! Dowels much cheaper!

You said valve grinding compound but I wonder if a rougher polishing compound would work like a blender bar or emery bar? I also have some Flitz. (I ask because I already have those handy)

I just remembered I do have the cratex abrasive sticks. I could shape those to a cone and see how they do. I fear they are too soft though and deform ... or maybe that is a good thing? They work great for jeweling though.
 
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Stacy E. Apelt - Bladesmith said:
All the above will work, but won't necessarily polish the edges evenly.
Lapping the entire surface with a wooden cone will smooth out every scratch and polish it as high as you wish to go. It is also really fast.

Here is a simple sketch of what I am talking about. Just thin the end of the dowel to fit the hole and apply some grinding compound to the lip. It will shape to the hole bevel and smooth everything nicely.
Click to expand...
I have tried using the valve grinding compound and not gotten great results. I tried it with both a steel rod and a dowel shaped to the angle of a drill bit, the wood was better than the steel but was still kind of dull. It I pressed too hard the dowel deformed so I was doing consistent pressure on a medium drill press speed.

I tried using cratex rubber abrasive rods shaped to a drill bit angle as well. They definitely made it a little more shiny but they weren’t aggressive enough to get rid of circular lines.

Not sure if I am doing something wrong or it just takes a long time? Was thinking about rough buffing compound on a dowel but haven’t tried that yet. I am going to polish the Damascus blade before etch so I am afraid that any lines in the divots will stand out even more.
 
Indasa makes rolls of adhesive backed Rhynowet, it sticks securely and doesn't leave anything behind. You could maybe stick it to the cone shaped things you were using?
 
Going straight from a bumpy milled surface to a polished one in one step with polishing compound might be a big ask. Some countersinks leave smoother bevels than others.

I have never had good results with the old fashioned multi edge engineers countersinks.

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I have had better luck with a new, sharp, three blade cutter, but have heard some others give even better results. Quality definitely matters. I have found that using the same countersink to hog out general countersinks then hoping to get a super finish from it does not work well. I now try to keep one or two sinks just for finishing. Running them hard into the edge of a drilled hole can cause dinks in the edge that translate to lines on the finished bevel.

I have only a small carbide countersink for my smallest of holes, but that gives the best finish of the four sinks I own.

As an intermediate step I have had good results using a 90 degree carbide burr. My countersinks are also 90deg, angle matching also matters. Only then do I go to the bevelled rod and compound. I file some grooves into the bevel to help hold compound too. Diamond lapping paste worked better than the other polishes I have on hand.
Still slow, but not as bad as trying to take a bevel off my roughing sink straight to polished.
 
You could try purchasing some emery sand (available in that big online store ;) :)) and glue some to your dowel with some strong preferably heat resistant glue. We used to do that on out glazing wheels at the knife shop and it worked quite well. Of course bolsters have a lot more surface area than a countersink so it's possible that that grit will be worn away quickly but it might be worth a try. The sand is fairly cheap.

Eric
 
here you go

www.instagram.com

Tim Wright on Instagram: "A few years after I started making knives I came up with a nice way to finish lanyard holes. It takes 15-20 minutes, no special tools and a mild skill set. It works so well and is so simple that I figured eventually other ma

56 likes, 13 comments - timwright259 on January 17, 2020: "A few years after I started making knives I came up with a nice way to finish lanyard holes. It takes 15-20 minutes, no special tools and a mild skill set. It works so well and is so simple that I figured eventually other makers would...
www.instagram.com www.instagram.com

you could also use cratex polishing bits that fit in a dremel
 
HSC /// said:
here you go

www.instagram.com

Tim Wright on Instagram: "A few years after I started making knives I came up with a nice way to finish lanyard holes. It takes 15-20 minutes, no special tools and a mild skill set. It works so well and is so simple that I figured eventually other ma

56 likes, 13 comments - timwright259 on January 17, 2020: "A few years after I started making knives I came up with a nice way to finish lanyard holes. It takes 15-20 minutes, no special tools and a mild skill set. It works so well and is so simple that I figured eventually other makers would...
www.instagram.com www.instagram.com

you could also use cratex polishing bits that fit in a dremel
Click to expand...
Thanks for the tip, I may use that in the future but I am talking decorative divots, they don’t go all the way through. Just about 1/3rd the blade thickness.

I am trying the cratex and it is making it shinier but I still see lines. Going to go up to the next grit to see if the lines are left by the cratex itself or are from the drill bit itself. I’ll try to post a pic but I don’t have an upgraded membership anymore so not sure if I can.
 
Ah, missed that they didn’t go through. The repeated use of the word “hole” gave me the impression that you were talking through holes. Not sure I have a clear picture now of the shape you are trying to polish, diameter, depth, flat bottom or conical.

Can you share a photo? ImgBB?
 
C_Claycomb said:
Ah, missed that they didn’t go through. The repeated use of the word “hole” gave me the impression that you were talking through holes. Not sure I have a clear picture now of the shape you are trying to polish, diameter, depth, flat bottom or conical.

Can you share a photo? ImgBB?
Click to expand...
I am filling just deep enough to get a shallow divot the size of the drill bits width. So it is 135 degrees at the bottom, about ¼” wide, and maybe 1mm deep.

The cratex is actually working decently. Went up to the finest level and got a decent shine but still has some swirls. Hopefully they disappears among the Damascus in the etch. I could try buffing compound I suppose
 
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