Main Table Alignment

[reubenjames]

It may sound like it in some of what I post but I do not get riled up. I outgrew that way way back in my military days.

No, I know. I've worked with enough customers via digital communications that I can usually tell. I couldn't think of a good word, though. Maybe, "Just to see how long you will reply to this thread," would have been more accurate.

Agreed about the blades, but if I don't measure my blade flatness with a dial indicator, then I don't know that it's far enough out to be thrown away. If I'm *only* using my jig, I very well might not catch it. That might go back to "verify, not set, with dial indicator" but I'm just saying the dial indicator has its place, and for my process, it was no more onerous to use than a dowel. Actually, less so, since I didn't have a dowel of appropriate thickness, but my dial indicator attaches conveniently with a 1/4" bolt and nut to the miter gauge faceplate.

[JPG]

Why a 'dowel' in the miter gauge? What happened to the SS toolit?

[reubenjames]

Toolkit? I'm going by instructions in my manual and in PTWFE

[JPG]

Toolkit? I'm going by instructions in my manual and in PTWFE

Well maybe your instructions and PTWFE are not old enough.

Mine say use the 5/32" wrench in the miter gauge stop rod holes.

[keakap]

Per my manual, even the sanding discs can have a high spot--the alignment instructions, by the book, have you find and mark the high spot (and have you use or navigate around it during alignment). The disc *might* be "flat" but that doesn't mean the disc is perfectly perpendicular to its own spindle.

Also, I don't think they typically are perfectly flat, since a sanding operation is moving at high enough speed that the sander can still sand flat, even without the disc itself being perfectly flat. You'll get slightly more wear on the high spot, though maybe not noticeable. The high spot is noticeable during alignment, however.

Some good points re discs imho. It's roughly where I was when I decided I wanted at least one sanding disc that was definitely flat, as in no high spots. I will not recommend any particular way to do it, but suffice it to say my methodology was simply running the bare disc and removing any high areas.

I use the disc for alignment checks and that sort of thing, and for sensitive sanding work sometimes. It stays flat. And I am much happier with it than I was without it, regardless of how efficient- or not- it is.

[in fairness I should mention that my Conical system gets more use than the flat discs}

[keakap]

I have come to believe that we make far too much of precision when doing alignments in the wood shop.

... but please tell me how a .005" (or even .015") misalignment of the main table miter slots to blade or fence to blade will adversely effect performance in the shop.

I think you've pinned it down. And I think I agree.
After all, isn't the key (or only) critical dimension the difference- and maybe location- between the blade plate thickness and the kerf?

{to envision that try imagining a "worst case" scenario- a blade whose kerf is less than the plate thickness}!

[reible]

I began to question my vision of how the alignment numbers all add up and if the .005" number is reasonable or is it perhaps to tight a number and if it should be more in the range of .015".

I sent several hours watching videos by "known experts" people who I think are worth their salt and know of what they speak. Now this set of people may or may not be the same people you would respect or think of as experts but I do.

After doing this I think perhaps the .005" is too large a tolerance rather then to tight. It seems the .001" is a target and perhaps you are good at .002" and on the outside .003". In my personal case I find .003 as a common number with the shopsmith and the hardware I have. If it were to be .005" off I wouldn't try to get it any closer but if it were off more then that I would. For some others that number is .003".

So as a result I'm still happy with the .005" number and am sticking to my guns on that as a reasonable number.

No one seems to have a point at which the end of the world happens either so I can't tell you where the likely hood of kick back happens or when the wood will end up with burn marks or the saw will simply no longer be able to cut.......

Even just everyday posters seem to stick to small numbers, in the order of .003 to .005 and while that might just be regurgitated number or actual fact I don't know but no one is say .015" is what to shoot for.

So we are back to doing as you see fit or doing as the experts say.

Ed

[dusty]

You'll get no argument from me. I know what my machines are capable of and (more importantly) I know what I am capable of.

There was a time (before cataract surgery) that I could not distinguish the 1/64" mark. I can now see. This means that what was once close enough is no longer.

My two machines will align without a great deal of difficulty to a .002"-.003" tolerance. I have said in previous posts that my pseudo standard was .005". I could still live with that but why.

I can adjust to a tighter tolerance and the machines will hold that tolerance. However, I do not move my machines around much. If they were constantly rolled in and out of the shop area where they live this might not be a true statement.

I see no reason to disagree with anything Ed has stated.

With regard to kick back, I don't believe that misalignment is the most likely cause of "kickback". I lay that off on technique. Keep the work piece under control, tight against the fence until it has gone past the outfeed side of the blade and kickback becomes a none event.

[jsburger]

You'll get no argument from me. I know what my machines are capable of and (more importantly) I know what I am capable of.

There was a time (before cataract surgery) that I could not distinguish the 1/64" mark. I can now see. This means that what was once close enough is no longer.

My two machines will align without a great deal of difficulty to a .002"-.003" tolerance. I have said in previous posts that my pseudo standard was .005". I could still live with that but why.

I can adjust to a tighter tolerance and the machines will hold that tolerance. However, I do not move my machines around much. If they were constantly rolled in and out of the shop area where they live this might not be a true statement.

I see no reason to disagree with anything Ed has stated.

With regard to kick back, I don't believe that misalignment is the most likely cause of "kickback". I lay that off on technique. Keep the work piece under control, tight against the fence until it has gone past the outfeed side of the blade and kickback becomes a none event.

I absolutely agree Dusty. Once aligned the SS stays aligned unless you abuse it. I also agree with your comment on kick back. It is user error most of the time. I have never had kickback on the SS. I did have it happen one time on my router table but that was my fault.

[reible]

Since we are looking at the subject here is an interesting posting on kickback and yes pinching can be a factor. So believe it or not it is an alignment issue. Now if you are like me and like to use guards and the top guard in particular it is unlikely you will see any wood flying back at you but if the wood does pinch due to bad alignment it will burn and or stall the saw.

There are a lot of other potential ways to have it happen so just having the alignment right is not going to prevent it but you don't want it adding to the mix.

And as stated "By far the most common cause is binding or pinching. This happens when a piece of wood becomes trapped between the rotating blade and a stationary object, such as the fence or the guard. The following is a list of reasons that stock can kick back:"

Any way have a read:

http://www.popularwoodworking.com/techniques/kickback

Ed