Log pulls away from rear dog when passing blade

[Ron Wenrich]

I ran a left handed mill for decades.  I would have problems with used saws that were from right handed mills, but dished for a left handed mill.  It seems that the saw has memory from the original manufacturing and wants to go back to the original shape.  He always had problems with switching the dishing.  We ended up going with new blades and that solved the problem.

Have you had a saw doc look at your blade?  There may be a crack in the saw, and that will mean its good to use as a sign. I had that happen on one of my saws, and it was fairly new.  A saw doc should be able to point you to any used saws that are out there in your area. 

[Fearski]

Have had saw doc look at it 3 times. It was a right hand blade for first 90 years of its life I had doc switch it . Could be the problem.not sure thanks

[cutterboy]

It was a right hand blade for first 90 years of its life

Good God!! How long do those blades last?

[Ron Wenrich]

I've had guys tell me they have had blades that last for decades.  A lot depends on how much abuse a blade is subject to.  Metal strikes are really hard on sockets.  It stretches them out of shape.  It also bends socket tips out of shape.  Eventually shanks won't stay in the sockets, even the oversized ones.  Heat is also a destroyer of blades.  Hanging a blade stretches steel. 

Generally speaking, its how many million feet of lumber you can put through a blade.  I circulated blades at about every 1-2 MMbf.  I was cutting grade hardwood.  When I circulated, we put new shanks in and had the saws hammered.  Generally, it was done before winter set in and you need really good shanks.  A set of teeth lasted about 75 Mbf.  When you get a good saw, you'll know it.

[DanielW]

I can't add much more to my first post, but one thing you said is rather concerning:

You said you put a 40" saw on and it ran fine. How did this work with the existing guides? I assume you had to modify the bracket and move them further in? If you're using the same guide position on a 40" saw as a 46" something must be awry. You want your guides to be just below the shanks. Guide location for a 40" saw would be far too close to the mandrel for a 46" saw, and running the larger saw with the guides that far in would be a little concerning, and possibly part of your issue.

It could very well be a bad/worn saw, but your saw doctor really should be able to tell that (if they're experienced in inserted tooth saws). A smaller saw will mask a lot of problems, however, so don't immediately assume the old saw is the culprit.

Can you post some pictures of the original saw and the mill? What's your lead set at? What style of tooth? Are the bearings keepered so they don't slip/deflect? Have you put a tach on to verify the RPM? Pictures & videos might tell a lot.

[Fearski]

Still working on mill I replaced the blade made a huge difference can actually saw now . As stated above my mill is an old howel the carriage drive wheel is slipping and log won't go into blade to saw now. The drive wheel on this mill appears to be made of Rubber washers about 4 inch diameter that are compressed on shaft showing lots of wear . Any thoughts what to use to renew this pulley thanks fearski

[DanielW]

That style of flat-belt pulley was pretty common on a lot of mill and farm equipment. Not too long ago on the 'YesterdaysTractors' forums, someone posted about rebuilding one of those rubber disc pulleys, but I can't seem to find the post now. There was also a similar style of pulley that used compressed paper discs laminated together rather than rubber, and there are still lots of ag equipment restoration places that rebuild them for people restoring their old tractors. You could maybe contact these folks (link below) - they can probably help you out.

I'm lucky, because I work at a industrial mill equipment manufacturer, and we make our own pulleys all the time. We primarily make them for conveyor belts, but I've had them made for myself a few times for drive applications. It's not too hard: A couple of steel discs cut on the laser or plasma table with an I.D. the size of the shaft and an O.D. that matches the I.D. if your pipe of choice. Weld them (carefully) to the shaft and pipe section (the pipe is usually 4" or 6" Sched 40 piping that will be your new pulley). Turn the O.D. of the pipe true on the lathe, then send out for rubber lagging. There are still plenty of belt suppliers that lag steel pulleys with rubber, and they can also do herringbone or cross patterns to improve traction if desired. Erik's Industrial and Goodyear (the conveying division) are two common ones we use.

Or you could find an old conveyor belt, cut some of the rubber discs slightly oversize, clamp together on your shaft, and turn down the O.D. yourself. Turning rubber is sometimes a struggle, however: Most metal or wood-working tooling tends to grab and pull it apart. The places that we have put rubber lagging on our pulleys all grind it to the final dimension, rather than turn it. With really sharp tooling and an aggressive rake angle, you can usually turn rubber ok. We sometimes turned rubber & urethane wheels at my old job, and we'd always freeze the work piece it first to make it stiffer.

Or if you want to try a simple fix, you could try lagging the pulley with some old baler belting yourself, using some rubber cement and staples. Not precise, and your O.D. will be larger which may affect your speed. But I've done it on my old planer-matcher when I was in a pinch.

If you don't want to fab yourself, I'd definitely see what these folks have to say: http://www.paperpulleys.com/pages/frictions.html

[beenthere]

Do these help?