I've seen several people having to shim their jointer when setting it up, but I don't know what this means. I think most of the comments were in regard to a model with table extensions, specifically the Sunhill 6" jointer. What is shimming, why is it necessary, how is it done, and is it difficult?
This refers to placing shims between the mating surfaces of the central casting of the jointer (the part that houses the cutterhead) and the infeed or outfeed tables. This is done to correct misalignments (e.g. a sagging table) or to remove play in the adjusting mechanisms. It's done by loosening the adjustment far enough to allow placement of a thin piece of metal in the appropriate spot in between the mating surfaces. How thin, and what is the "appropriate spot", depend on the problem that needs to be corrected. Is is difficult? Dunno. My jointer was good enough right out of the box that it didn't need any shimming. Looks to me like the hardest part is figuring out how much to shim, and where: likely a lenghty trial-and-error process, not difficult but a PITA.
-- Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
Shimming is a method of adjusting the alinement of attached things (like table saw wings, jointer tables/etc) where one inserts thin metal into the mounts to adjust the alinement beyond what is possible with the standard adjustment methods
You can buy shim stock in thin sizes, and many folks make shim material from things like softdrink cans/etc
John
A very good jointer tune-up article posted by David F. Eisan a few years ago explains how to check for alignment of the infeed and outfeed tables. Basically it amounts to setting a straight edge across both tables in various spots including the diagonals and poking around with a .007" feeler guage to see if there are any voids. Then it is a matter of following the manufacturer's instructions which will most likely involve fooling with the gib screws. If all else fails with attempting to bring them in line, then you may have to go the shim route. The article says to use automotive feeler guages and start incrementally inserting them in the dovetail race-ways of the outfeed table (you are moving the infeed table alot and shimming there would probably not last long) until the tables come into alignment, then break them off leaving them in place. Since "sagging" is the usual culprit, it makes sense that you would be shimming the bottom part. We aren't talking about much here...he suggests starting with .001 and working up from there. With geometry you can kind of figure out that .001 at the shimming point can fix a much bigger gap at the cutter head.
My Delta 6" was doing well until recently. Yesterday I put new knives on it and went through the entire set-up procedure with both the Delta instructions and David's guide in front of me. I really flunked the "gap test" heading towards the cutter on the infeed side but by simply loosening up the gibs on the outfeed and resetting the table to the .06 above the cutter head assemby, everything came into line perfectly, to the point where a .003 feeler won't go anywhere. BTW, I don't have a fancy straight edge but my 4' drywall T-square on edge worked just great and I confirmed its results with a fairly new 4' aluminum level.
In my case I think the gibs were too tight and adjustments to the outfeed table, as infrequent as they occur, were forcing it out of line, like maybe the top one was holding firm but the bottom one wasn't (or the otherway around). In any event I think I have dodged the "shims" for now.
If anyone reading this wants David's article, I'll be happy to send it via E-mail. It is really quite good. Just drop "the -remove to reply-" part if you're interested.
It's in the archives...
djb
That'll work also!!! (That's how I found it).
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