Blade Parallel to miter slot????

[dancam]

Hey Folks,

Need some help or advice .

I'm trying to tune up my Unisaw (Right Tilt) and have been successful with all of the adjustments except getting the blade perfectly parallel to the left miter slot.

I'm using a 1/4" flat aluminium plate (Master Plate from Griz) and a dial indicator mounted on a miter bar. I set the dial indicator to zero at the front of the blade/plate and then move the dial indicator back. The best I can get it to is 6/1000" (I got here by loosening the four bolts holding the top to the cabinet and then tapping the respective corners with a wood block and mallet until I got to the above measure).

My question is; is 6/1000 of an inch the best I can hope for or should (in theory) I be able to get to zero (front to back)?

Thanks for your help.

Dan C.

[FredP]

try snugging up one bolt. not tight just snug then see if you can get it better. 6/1000 is not that good. i have the same saw and its within 3/1000 maybe better if i can trust these eyes! what i found was i had to work with several positions to find what bolt to snug up. hard to splain but i think you can get closer.

fred p

[dancam]

Mike,

I'm using a rectangular aluminium plate instead of the blade. As FredP said, I should get better than 6/1000. I'll try going back to the drawing board tomorrow and try again.

I'm afraid I'm going to have to take the side table off and the Uniguard off so the table top has nothing connected to it. Then I can try the again.

Thanks for the input.

Dan C.

[dancam]

Hey FredP and Mike,

Thanks for the advice. I spent a couple hours this AM and took apart the Unisaw. I removed the Unifence rails and also the Uniguard rail from the rear. Previously I had only loosened the bolts holding the brackets but I guess that didn't give me enough wiggley room to move the table top.

Anyway, long story short; with all of the hang ons removed I lossened the top bolts (kept one corner snug per your suggestion FredP) and was able to line up the miter slot parallel to the master plate to 1/1000th of an inch. I tried for zero but LOML told me I was anal for all the cursing and that I should be happy to be within a hair of perfect.

Anyway, thanks again for the counsel and support.

Dan C.

[sapwood]

Glad you got it figured out Dan!
Fred and Mike's advice is dead on Mike and his son installed a new arbor on my Griz and achieved perfection utilizing the "snug, but not tight bolt" procedure along with a few trial and error bangs on the corners. Probably would have taken me 20 hours, but some folks (like Mike) have an innate knack for such

Roger

[Howard Acheson]

>> is 6/1000 of an inch the best I can hope for or should (in theory) I be able to get to zero

At a minimum, a tablesaw should be no more than 0.003" but you should be able to get to 0.002".

You have already spent the money but for others, here is a 5 cent alignment tool for tables saws.

Here is the low tech, low cost way to align a tablesaw that I learned maybe forty years ago and teach to my students now.

Make 3/4 x 3/4 x 12" hardwood stick. Drill a hole somewhat centered in one end and insert a brass #8 x 1" round head wood screw about half way. UNPLUG THE SAW. Raise the blade completely up. Clamp this board in your miter gauge (if you determine that there is some slop in your slot to miter gauge, use a playing card to take up the slop) so the screw head just about touches the blade at the front. Now rotate the blade by hand and determine which tooth is the closest. Adjust the screw in or out until it just touches this tooth. Mark this tooth. Rotate the blade so the tooth is now at the back of the table and move the miter gauge/stick assembly to the back and see if it touches the marked tooth to the same extent. If it doesn't, adjust the trunnion (if a contractor saw) or the tabletop (if a cabinet saw) until it does.

For a contractor saw, first use a small c-clamp on the rear trunnion and cradle to keep the assembly from moving. Then loosen the two rear trunnion bolts and one front trunnion bolt. Slightly loosen the other front trunnion bolt and use a stick to tap the trunnion until the blade and screw lightly touch. The blade does not move directly around the center so you will need to repeatedly go back to the front of the blade, readjust the screw, and then again measure the back. Be sure to check after tightening the trunnion as the trunnion frequently moves when being tightened.

For cabinet saws, loosen three of the bolts that hold the tabletop and tap one corner until things come into alignment.

The same adjustment gauge can be used to set the fence parallel to the miter slot. Slide the miter gauge to the front of the table and move the fence over to the screw head and insert a playing card between the screw head and the fence just so you can move the card as it touches both the fence and the screw head. Now move the miter gauge to the back of the table and see if you have the same feel when you insert the card. I like my fence absolutely parallel--if you want to have a slight opening to the fence, you can easily estimate the opening by adding a thickness of paper to the card.