Simple Sharpening Question - Touch up Points Between "Real" Sharpenings?

Trent · March 12, 2008, 12:15:52 AM

Does anyone touch up the points of blade teeth between regular sharpenings? I understand the importance of getting a proper set and getting rid of the micro cracks when it comes time, but could I get some renewed life from a blade with a file or mini grinding tool? It seems like this could even be done on the mill.

I'm not scared to try it but need to know which side of the tooth to work on. Is it the left or right side of tooth in CAD drawing below?

Thanks

___________________________

Blade

_______ _______________
\ \
\ \
Left \ \ Right
---------> \ \ <--------
\ \
\

LeeB · March 12, 2008, 03:22:51 AM

You might get a few more boards between sharpenigs by dressing the face, but you won't be doing your blade any favors,and end up with less overall blade life.

bandmiller2 · March 12, 2008, 06:04:57 AM

Trent,bandmill teeth should be sharpened straight across their temper is a little too hard to file well.Grinding is your only real option.The trouble with small die grinders and small stones you tend to round over the tips.If your set is OK and you can repoint the tooth right you could go one sharpening ,second time take it off and give it a real sharpening ,gullet and all.Frank C.

ely · March 13, 2008, 04:11:53 PM

i would not advise the attempted filing of a band saw blade :

because once upon a time that was me out in the shop trying every file in my arsenal. to no avail. i always claimed that i could sharpen anything that was supposed to be sharp. that was not true on a bandsaw blade, i really had no clue.
once i bought the proper machine it is a piece of cake. with icing.

when i was trying to do it the hard way , it felt similar to banging my head on a wall.
sharpener and setter= money well spent. 8)

kderby · March 13, 2008, 05:20:08 PM

Trent, I have explored this question as well. The blade portion that does all the cutting is four thousanth's of an inch. Seems like there would be a way to touch that portion of the blade up. I have not figured out how to do it correctly. Perhaps a few strokes with a diamond hone?

The set and the gullet are important issues for blade grinding but do they need to get done every time?

KD

redprospector · March 13, 2008, 10:06:30 PM

In my experience, you need to grind gullet and all every time.
I once had an old ancient WM sharpener that only ground the face of the teeth, the blades didn't last too long. Every time you touch up the face of the tooth you are changing the shape of the gullet, not much but it is changed. After about 3 or 4 touch ups it becomes verry evident in the cut.
Besides all that, it would take just as long to touch it up as it would to sharpen it.

Andy

barbender · March 14, 2008, 10:39:47 PM

I've always been watching for a large diamond file for this very purpose. For us guys that 200 board feet is a big day of sawing, touching up your blade can mean the difference between sawing on saturday or waiting a week to get your inventory of 2 blades back from the sharpening service.

redprospector · March 16, 2008, 08:11:05 PM

Quote from: barbender on March 14, 2008, 10:39:47 PM
I've always been watching for a large diamond file for this very purpose. For us guys that 200 board feet is a big day of sawing, touching up your blade can mean the difference between sawing on saturday or waiting a week to get your inventory of 2 blades back from the sharpening service.

Suffolk Machinery used to (and may still) have plan's for a freehand grinder. It's made from a 6" bench grinder, one of their grinding wheel's, and some flat iron. I made one years ago and still use it. I'm sure compared to the auto sharpener's it is lacking, but once you master it it's surprising how well it does. I can sharpen a 14'4" band in just under 5 minutes (not counting setting the teeth).

Andy

Grawulf · March 16, 2008, 09:25:11 PM

I've been wrestling over posting on this thread for fear of being roasted over my own sawdust.........I'm Scotch...last name McKay or McKee so I come by it honestly - I'm cheap!
I've been sawing for approx. 5 years - the guy I bought my mill from said when you dull a blade, just throw it away. They aren't that expensive. I'm thinking you've got to be kidding!
I started experimenting with a dremel. I knew I couldn't maintain the whole profile so I started back cutting the tooth - figured the point of the tooth to be the most important part since that's the first thing to present itself to the log. Back cutting the tooth doesn't change the hook. It just makes it sharp again. The face of the tooth is slightly rounded from wear but the point again does what it's supposed to do. I can get approx. 12 - 1500 bf before failure due to not grinding the profile and eliminating the micro-cracks. Each time you take a little off the back of the tooth off, you lose a little set, but it's not enough to affect the quality of lumber. Only thing I've really noticed is a slight burn caused by lack of set - usually just before the blade snaps. I can touch up a blade in less than 5 minutes and can get another three to five hundred board feet before another touch up. I would really LOVE to have an automated sharpener and set but can't justify the cost at this time. Maybe when I retire and start sawing full time............

So, in my experience, it pays for me to touch up.

kderby · March 17, 2008, 11:31:30 AM

Grawulf, I think you are on to something. I had not figured out how to use a diamond hone and cut the tooth angle with precision. Going after the back of the blade is a good idea.

Again, the portion of the blade doing the cutting is four one thousanths and I understand that sharpening/profiling takes twenty one thousanths. I still want my blades to be profile ground, just not as often.

Sharpening , as mentioned, would only take five minutes. I don't have a sharpener. Every time I ship a blade it costs me cash. I could send the blades after one touch up and cut my cash out lay for sharpening in half.

I am still just toying with the idea. My mother is a MacDonald. Scottish (cheap/thrifty) is thick in my blood as well.

KD

logwalker · March 17, 2008, 08:57:30 PM

KDerby, could you expand on the 4 thous. cutting surface. I am not following you. As to sharpening yourself I think the technique described in other threads to be very practical. Basically it is dressing a 3/4" wide grinding wheel and using a painted guide mark on the table at the right angle to guide you. Move the blade directly toward the wheel and dress the whole face and back of the tooth in one motion. I think a several sawyers are doing this. Joe

kderby · March 18, 2008, 01:34:13 AM

Log Walker, If I have my information straight, the part of the blade that cuts is the point. The gullet is for material removal and the remainder of the blade is for strength. The blade point has a cutting surface that is miniscule.

I got the four thousandths reference from Wood-Mizer.

I am fascinated by that number. It is the point of the point that slices the wood. When that tiny point is dull, the entire blade is dull. It is that point I would like to touch up. If there is a way to touch up that point without losing too much set, or letting gullet cracks run wild, I think it would be economical to pursue that method.

This would be like stroking a chef's knife with a steel rather than going over the knife with a grinding wheel. Will two strokes with a diamond hone sharpen the tiny point of the tooth that cuts the wood?

I also want to add a disclaimer to this discussion. The price of a blade cutting the wood is a tiny fraction of the cost of making lumber. I use Re-sharp and I am a happy customer. I have my crew change blades at the first signs of dull (blade walks over the knots rather than through them). This is just an exercise in curiosity for me and not a jab at blade experts or blade makers. ;D ;D ;D

Kendall

bandmiller2 · March 18, 2008, 06:00:15 AM

Before I got my cooks sharpener I used the Suffolk method that is a bench grinder with a 3/4 shaped stone.It's just a bench grinder with a small table marked off with the proper angle.You kiss the gullet with the side of the wheel at the proper angle and bump the tooth face into the wheel you get a system and it goes rather quick.It's a job best done before miller time.It is very tiring on the hands and wrists were I to do it again I would put a roller support overhead to support the band wile I'am feeding it to the grinder.Its quite easy to make a setter with a de-stak-o type toggle clamp and an old dial indicator.Frank C.

logwalker · March 19, 2008, 01:09:33 AM

KDerby, It is easy to find out if you are getting the edge sharp if you use a magnifying glass in a good light. I use one of those magnifiers with the round fluorescent bulbs. I can really tell what is going on. No guessing. And with a sharper tooth there is a lot less pressure on the tooth so less strain on the gullet. So it makes sense what you are saying. Let us know how it works. Joe

moonhill · March 19, 2008, 07:08:19 AM

Here is a 3rd post for the Suffolk/bench grinder method. Very cheep and effective. In fifteen years of sawing I have never sent a band out for sharpening. 6 minutes and 2 times around and done. The tips are sharp, and the gullet clean. Tim B.