Hammering a saw blade....

[mrcaptainbob]

Visited a fellow today that has an old saw mill with a 40" blade. He thinks it may need to be hammered. It looks to be in pretty good shape, no missing or bent teeth. How might I find a shop here in south central Michigan (Jackson/Hillsdale County area..) that does work like this?

[Jeff]

Call Menominee saw our sponsor. They may have a sales route near you.  Tell them the Forestry Forum sent you, info to the left.  Peach is the name of the very experienced saw doc there.

[weisyboy]

hammering or rolling is done on cerk saw blades, to Tension them.

when a large dist is spun at high speed the centrifugal force throws the outside of the blade outwards causing it to expand, normally this would make the outside bigger then the inside and cause it to wobble, hammering or rolling expands the inside, so the blade will be dished to start with as it spins up to speed the outside throws out and makes it streight.

the blade needs to be tensioned for the right speed, if you watch a saw blade starting up it will wobble untill it gets to its optimum speed then stand up dead streight, a little faster and the tail of the saw will start to whip, cos it has expanded beyond the inside diameter.

a sawblade that is not properly tensioned will cut crooked, heat up, leave bad saw marks, and just be a real pain to use.

hammering or rolling must be doen be a qualified person, it takes skill and practice to get right.

[Quebecnewf]

How often would a cir saw blade need to be hammered. The reason I ask there were cir mills in this area and I never heard of the term until I camo on this forum.

Maybe thats the reason some of these local mills produced bad lumber

Quebecnewf

[Jeff]

This may sound like I am being curt, but they need hammered when they need hammered.  If the saw is not hammered properly, it is not going to saw properly. I've went as long as a year or so without needing a saw tensioned. In my case, that was probably over 3 million board feet. I've also went a day. Newly tensioned saw getting hot because a stick got caught between the off bearing table and the saw plate and I didn't see it. The saw turned to butter and the damage was done.   If a sawmill is sawing regularly, eventually the saw is going to need to be tensioned.

[bandmiller2]

Quebec,usally production mills will have a saw hammered once  a year usally going into winter.As Jeff says heat the plate and all bets are off.Us small time millers can go for years if we're carefull.My first mill I had a foolish and expensive misstake,a newly hammered saw I let a small sliver get lodged between the deck and the saw heated it and started snaking.When I took it back to the smith he smiled and told me just what I'd done before I opened my  mouth.Frank C.

[dail_h]

Just started sawin with the belsaw coupla days,,gettin the feel of a circle rig again. Hung the saw in a log ,,, finaly got it out,,looked ok     wouldnt saw atall,,run worse'n a drunken sailor. trip to saw doc,,all good again
Love the song of circle,,, ;D, old tractor aint too happy tho

[bandmiller2]

It takes real power to run a circular mill properly.I have an old ford industrial diesel[dagenham] 6 cyl.that was 100hp in its prime probibly lucky to get 75/80 now the simms inline injector pump is getting worn.Shouldn't complain though the mill will work me down to parade rest,and works good enough.First mill had a cat D318 that had plenty of moxie,but even that felt the big oak logs.With light power units you got to keep your bits vicous sharp and be prepared to slow your feed. Frank C.