Different tooth spacing......wierd

[Jim_Rogers]

Ok, so being that the wind chill is something like 2° outside here in New England today, I decided I'd sharpen some blades.

I have this box of old blades that I got in trade off of a customer. He had a mill once and sold it some years ago. But he didn't let go of all his blades. I bought some off him for $6 a piece, off of his sawing bill.

I have used some of his blades after sharpening, and they were average and I got some good lumber from them.

I set aside these last 5 or 6 blades to do at some other time. Well this is that time.

So, I was sharpening this blade and found this:



 

I have never seen a blade with the tooth at the weld off this much.

I highlighted the tooth spacing with red lines so that it may show up better here online.

But this tooth is way off. This can't be a WM blade. even though his mill was a WM.

I seemed to process through the grinder alright, just a little weird.

Has anyone seen anything like this before?

Jim Rogers

[ladylake]

  No big deal, just sharpen and use them.   Steve

[Bibbyman]

I had one Wood-Mizer blade last year that had one long tooth spacing at the weld.  It was just long enough the sharpener claw would not pick up the next tooth to advice.   I don't know for sure if it came from Wood-Mizer that way or if I did something to it.   But it was at the weld.

[ladylake]

Also that almost looks like a negative hook, the grinding wheel needs to be profiled.   Steve

[ely]

ive seen that alot along time ago when i used bands from less than reputable sources. i never really had a problem with the bands just a little different sound as they went thru the sharpener. evened right out after a few times.

had a couple bands back then that were made from severl short pieces of band stock, i noticed because they had several welds in them.

[Jim_Rogers]

Also that almost looks like a negative hook, the grinding wheel needs to be profiled.   Steve

I dress the stone after every blade, or before every blade. Maybe I should dress it some more.....

Jim Rogers

[ely]

jim do you dress the part of the stone that grinds the tooth face?

i see what the comment was made about., when i first started sharpening bands i made the mistake of taking some off the back of the stone that grinds the face of the tooth. after i "sharpened" a band it would not cut for me... i just about pulled my hair out on that one.

if you ever grind the back of the stone, or wear it by grinding the face too hard, you will have to dress the stone until it gets back up to where the back of the stone is fresh. my opinion anyway.
messing with the backside of the stone is like adjusting the degree of hook on the sharpener only without much control on it.

[Jim_Rogers]

I only dress the grinding section of the stone, not the side. By grinding section I mean the outside perimeter. I never dress the sides.

I believe that many times this subject has been discussed here.
And even photos of the stone dressing stick's position posted. I am, I believe dressing it correctly now, and that is parallel with the grinder motor arbor. Which should be 90° to the side of the grinding stone wheel.

I don't round the inside corner; I let wear do that. I do dress the slope of the back side of the tooth so that it is shaped correctly. If you don't then it won't grind down into the gullet and remove the micro cracks.

Again, I may not be dressing it enough to get it straight on the tooth side.

I'll look at it closely tomorrow.

I have to change my cam and sharpen some 4° blades tomorrow. And I can inspect the stone carefully and make sure it's working correctly. And redress as needed.

Jim Rogers

[drobertson]

I have found that tooth spacing is variable at the weld at times, but have found the next tooth not following the progressive set, I have since started at the and for the most part sets have been consistant as to inside outside straight, if that makes any sense.

[just_sawing]

Sharpen blades for customers and one of the places they purchase from is a shop in Morrison
I find that the set changes at the weld and the space at the weld can be anything. I love WM blades for their consistency

[Chuck White]

Shouldn't be too difficult to sharpen that band.

The first one to be the one on the left side of the weld.

The feed arm should not go beyond the second tooth to the right of the weld and then the band would feed as normal.

When the grinder sharpens the second tooth to the left of the weld, turn off the sharpener.

[pineywoods]

Back before WM came out with the doublehards, we used to break a lot of blades after 2 or 3 sharpenings. I ground the broken ends off square and took them to a sawshop that had a resistance welder. Welded them back, that worked fine, but the tooth spacing at the weld usually was off by 1/8 inch or more. The old woodmizer drag type sharpener never even noticed. I do some sharpening for a couple of norwood owners. Don't know where their blades come from, (not woodmizer) but I frequently notice short spacing at the weld and have run into a few with multiple welds. Also some strange gullet profiles.

[LeeB]

It looks tome like your sharpener is alowing the blade to slip in the clamps a little during the face grind and leaving you with the rounded face profile. Check for crud build up around the tension springs. I used to have this problem a lot with my old WM sharpener. The springs may also have gotten weak. If I remember right, they can be adjusted some to make the clamptighter. Next time you sharpen, watch the blade and see if it is moving forward a little during the face grind.

[Migal]

Jim
     When I ordered blades from a sponsor he asked if i wanted them exactly the dimension or add for tooth spacing I wanted exactly dimension so at the weld the spacing is off Is no big deal to me as of yet I don't sharpen my own.

[hamish]

Most if not all band suppliers allow for spacing at the weld that is less than the regular spacing, but try not to have any spacing greater than the regular pitch, as they know it creates havoc on indexers.

[Jim_Rogers]

It looks tome like your sharpener is allowing the blade to slip in the clamps a little during the face grind and leaving you with the rounded face profile. Check for crud build up around the tension springs. I used to have this problem a lot with my old WM sharpener. The springs may also have gotten weak. If I remember right, they can be adjusted some to make the clamp tighter. Next time you sharpen, watch the blade and see if it is moving forward a little during the face grind.

I did clean the clamp set up before I began this sharpening session.
I have done that many times.
I have looked at the springs since you suggested that they could be "tighter" and there isn't much between the spring loops right now. If I turn the bolt in another go around then the springs will be pretty much bottomed out with a blade in there.
I may look at it more closely when I have a blade in there.

I have the older style clamp with the two toggle handles on the heads of the bolts to flip for open and closed.



 

I just completed the change over from 10/30 blade grinding to 4/32 by changing the cam and adjusting the angle of the grinding motor.

While I had all the tools out, I took up one turn on the left hand spring bolt, with the blade in place.

You can see there is still a gap between the spring loops on this left side, in the above picture. And you can also see the gap between the loops on the right hand side.
I couldn't easily access the right hand bolt's jamb nut to loosen it to take up one turn. I'll have to wait and do that next time I clean it.

I've just started the second blade and it seems to be running alright now. And I don't see or hear any slipping. I'd know if it was slipping by the sound of the grinding wheel grinding off a tooth. I hate when that happens.

Thanks for your advice.

Jim Rogers

[Tom L]

here at the shop, all of blades I use to cut metal with are variable tooth,   2-3 4-6 ,5-8 ,tooth spacing, helps the saws run smoother . I never seem to see any wood blades with variable teeth. has anyone ever experimented with variable tooth spacing on a wood cutting blade? may make a difference on tough to cut materials.