Replies

1. 
   splintergroupie | Aug 01, 2004 12:28am | #1

   I don't know what you mean aobut your fence being "open", but a misalignment of the fence can cause this, as well as case-hardening (a kiln problem you can't do anything about), the natural stresses in the wood being relieved and realigning the board (also beyond your control), and one other i can think of that is often the culprit and easily fixed: a dull blade or slow feeding (or no kerf-splitter) which causes the sawn edges to overheat.

1. 
   BG | Aug 01, 2004 02:56am | #2

   Splinte,

   What I mean by 'open' fense is a few thousands or so toed out to prevent forcing the wood into the back of the blade...from either case hardening or whatever.  I noticed the other day that few thousands had greatly expanded to more like an 1/8 to 3/16"...so maybe that is my problem...altough I can't figure out how..

   Initially I thought the wood was to blame...but I've cut too many pieces of different species, etc. and gotten the same results...

   My blades could definitly be dull... 

1. 
   splintergroupie | Aug 01, 2004 08:14am | #3

   1/8-3/16 is an amazing amount of space to have on the outfeed side of a blade. I keep mine right-on parallel.

   Edit: If your fence has shifted that much, i see a safety problem looming. It was a loose fence coming off the rails that let a hand surgeon practice HIS joinery on me.

   Edited 8/1/2004 1:17 am ET by splintergroupie

1. 
   BG | Aug 01, 2004 01:22pm | #5

   Splinte,

   I just noticed the size of the gap yesterday..I often use my sled with my fense when glueing up boxes to ensure square...the divergence was quite noticable.  A couple of weeks ago I had to pull off the fense a few times for some large stock and I may have handled the fense a bit roughly.  I'll make some adjustments today....I just could not figure out how the 'bow' was happening...unless case hardening...but the heat makes sense too...

2. 
   shoemaker | Aug 01, 2004 06:20pm | #7

   Maybe time for a new blade and possibly a new fence.Thats not a blemish....we call that character

1. 
   BG | Aug 01, 2004 08:23pm | #8

   Shoemaker,

   Naw..the fense is fine...it turned out that the allen screw (there are two which set the tightness to the rail and the perpendicualarness of the fense)had backed off a bit on one side...so depending on how I pushed the fense into position dictated how 'open' it actually was. A quick turn of the allen screw and everything was/is fine.

   Now, the new blade...that's a different story..I've been working two of them (24T, 40T)for almost three years now. 

1. 
   shoemaker | Aug 02, 2004 02:32am | #9

   well, glad to hear you found out the problem without injury.Thats not a blemish....we call that character

2. 
   BArnold | Aug 01, 2004 11:46am | #4

   1. Your fence should be parallel to the blade or up to a couple of thousandths toward the open side.  There may be arguments raised about this, but the bottom line is: line up three 'experts' they'll give your four opinions on it.  I prefer to keep the fence open by a couple of thousandths.  What kind of saw do you have?  Have you tried adjusting the fence?

   2. Even if the wood you're ripping tests to the right moisture content, the natural internal stresses can cause it to bow when ripping or immediately.  I've seen rips of expensive hardwoods bow as much as 1/2" over an 8' run.  Although it may create additional waste, I always cut oversize enough to allow for jointing the smaller pieces and re-cutting to make the edges parallel.  When possible, I allow rips to sit overnight to allow them to stabilize before final dimensioning.

   Bill Arnold

   Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

1. 
   BG | Aug 01, 2004 01:45pm | #6

   BArnold,

   I've got a Griz with a Shop Fox classic (Bies knockoff) and it is easy to adjust...which I will do and bring it back to a few thousands open. I don't have a jointer..no space...but I don't mind putting a plane to the edge.  It got a bit long in the tooth a couple of weeks ago with several panel glue ups including a ten board glue up...not the planing as much as in and out of the vice..(whew!) ..I did run several boards at a time through the planer on edge and that worked.

    As you say, its not uncommon to have some 'bow' on long rips.  I have been very fortunate not to have that issue for a couple of years...(as Splinte mentioned) maybe my blades are a bit dull too.  I do tend to stack and number my cuts and wait a few days (up to a week) before proceeding to the next step in the project.  Being a hobbiest, I tend to over organize so I can hop in and out of a project quickly and keep the scratching time to a minimun...