Finishing Flats

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Bltien

Joined
Feb 1, 2017
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Looking for some advice on finishing the flats/ricasso area on my blades. The main thing I'm wanting to do is speed up the process. I've only been doing some small batches of about 5-10 knives at a time, but I'm currently working on 20+ To save time and money on heat treating. The blades are CPM154 and are currently profiled with the little bit of scale on them.

I've been using the platen on my grinder , but it seems that the edges of my profiled blades always get the most contact with the belts and the middle is a pain to get finished. It also is a pain if I accidentally gouge the tang or spine when I'm trying to clean this up.

I'm thinking about saving time and hassle by alleviating this and leaving the flats textured. Also, I'm not a fan of hand sanding... and I try to be as efficient as I can.

Main question, what do you guys do before and after heat treat to get a good finish on the flats quickly? Belt progression?

What are good options/processes for textured flats that are relatively simple and fast? The knives I'm making for people are mainly edc, which they're more concerned about function than looks. Sandblasted flats?

I might just have a poor process for doing this and am over thinking it! I appreciate any help to speed this up.
 
I flat grind my tangs on the platen using a magnet holding the blank vertically. I usually go to 220 prior to HT. After HT, It depends on the knife. I like a contrast to the bevels, so if they are a scotchbrite, I sometimes go up to an A30 gator. Key is getting it FLAT. I will vertically grind throughout the bevel grinding process, since the belt is on there already. If that tang isn't dead flat, you will have gaps between it and your scales, and it WILL look like crap.
 
Your platen has to be perfectly flat.

With scale use a new 50 grit belt
 
Like others have said I just use my flat platen on my grinder... however I don't think it's perfectly flat so with a little hand sanding and a rinse repeat for the scales I've learned to make them match without having gaps or dips when attaching the scales to the knife. I'd really like to be more accurate and use a surface grinder or disk sander, maybe even a Travis Wuertz surface attachment but money and space is super limited right now.
 
A 9" flat disc sander is one of the most useful tools for a knife maker and also one of the best values.
For the cost of a motor, $150-$250, and a flat disc $100 you get things flat.
and hook it up to your VFD and you have a real useful tool
 
I have a glass platen. For CPM 154 I use 120 grit Norton blaze to get the mill scale off. I then go to 220 grit, and 400 grit. I send my blades to Paul Bos heat treating and when I get them back all I do is hand sand.
When I used to use ATS-34 I could use 220 grit to get the mill scale off but with the CPM 154 I need to use the 120 grit. With a sharp belt it goes fast.
 
Thanks for all the info so far. I'm not in the position to get a disk or surface grinder at the current time, but I'm thinking that'll be one of my next purchases. I tend to use belts longer than I should... so maybe just keeping a sharp belt on will solve some of my problems. I should probably look into the glass platen too.
 
Bltien said:
Thanks for all the info so far. I'm not in the position to get a disk or surface grinder at the current time, but I'm thinking that'll be one of my next purchases. I tend to use belts longer than I should... so maybe just keeping a sharp belt on will solve some of my problems. I should probably look into the glass platen too.
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I have found countless makers that say use belts like they are free. I agree with them. Sharp belts so work faster, and cooler. Win win. It may cost a little more but its better than ruining a HT on a knife. Or wasting a bunch of time on a dull belt.
 
Well I was able to get some work on them today and I noticed a couple things that helped. One, like many people have said and I usually forget about, is using sharp belts. Which one reason I think I was hesitant to switching is because I'm running low on my ceramic belts... Second is I realized I need to simply use more pressure when grinding. I think that made the biggest difference. It seems that I always realize this at some point when I'm doing a decent amount of grinding, but it's after I've wasted a good amount of time trying to grind with light pressure. Also when grinding it seems that the platen isn't exactly flat, so I think I'll be getting a glass platen in the near future. I haven't really looked into the glass platen... are there some better than others or is there a recommendation on one to go with? Thanks again for all the replies.
 
Bltien said:
Well I was able to get some work on them today and I noticed a couple things that helped. One, like many people have said and I usually forget about, is using sharp belts. Which one reason I think I was hesitant to switching is because I'm running low on my ceramic belts... Second is I realized I need to simply use more pressure when grinding. I think that made the biggest difference. It seems that I always realize this at some point when I'm doing a decent amount of grinding, but it's after I've wasted a good amount of time trying to grind with light pressure. Also when grinding it seems that the platen isn't exactly flat, so I think I'll be getting a glass platen in the near future. I haven't really looked into the glass platen... are there some better than others or is there a recommendation on one to go with? Thanks again for all the replies.
Click to expand...
USA Knifemakers has platens at a reasonable price and invaluable information about attaching them. If you query this forum for glass platens you will get a wealth of information and some really cheap places to buy.
 
The best and most consistent way like most say is with a surface grinder. Even if I'm going to handsand I use my surface grinder up to 600 grit to make sure the surface is dead flat and it doesn't have deep grooves from previous grits.

It makes hand rubbing a lot easier and faster.

Belts are meant to be thrown away, use them like that. You save yourself so much time which is money and you eliminate some of the issues that will cost you a lot more using worn belts.

If you are going to do it in a platen, get ceramic glass and get two magnets depending on how big your knife is. The way you apply pressure will always make one side grind more so press lightly then apply pressure to the bottom.
 
I got a glass platen on the way. I ended up going through high temp tools. Which they shipped very quickly... ordered yesterday morning and it shipped by the afternoon. I'm pretty jealous of you guys with surface grinders! But im still pretty excited to get the platen in haha
 
So...now that I have a big boy grinder on the way, looked in to buying a ceramic glass platen. Doing some research (and because I had to order some stuff from them anyway) found that McMaster Carr sells Glass ceramic at pretty decent prices, so long as you have the ability to cut the glass to the needed size (I have a cheapo wet tile diamond saw I use for cutting Carbon fiber and G10 scales, so that works). A 6 x 6 plate of ceramic glass costs less than $20.

https://www.mcmaster.com/#84815K49


On the old 2x42 Craftsman I used a piece of ceramic tile from lowes, worked for years, but the piece was too thick for a 2x72 platen.
 
Most local glass stores will cut the platen pieces to the size you want and do it at a reasonable price if you buy a few at a time.
Frank
 
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