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Blade alignment

3K views 18 replies 10 participants last post by  phlyers 
#1 · (Edited by Moderator)
Hopefully someone can help me out on this. I aligned my TS blade with the mitre slot with the blade ALMOST all the way up with my calipers and a Mag-Dro and the blade at a perfect 90 degree. I got it within .006" but for some reason it goes out of wack again when I lower the blade. Obviously I will need to raise and lower the blade a lot for different pieces but it can be inconsistent up to .040" sometimes .030" etc at different heights. It's an older Craftsman TS (113.29920) Could the height adjustment be messing with it? I checked all the trunion bolts thinking I left them loose but that wasn't the case. Thanks in advance.

Mike
 
#3 ·
with some saws, that is just the nature of the beast. you have to align the blade to the miter saw with the most used blade height as far as I can tell.

Also , I would try to do better than 0.006" alignment of blade to miter slot - I would try to get it under 0.005"
 
#4 · (Edited by Moderator)
Welcome to fine woodworking equipment made by craftsman ! Good luck with it !

Useless snarking. As a matter of fact, the 113 series of saws (made by Emerson for Sears) is actually a quality piece of equipment. I own one, a later model than the one he owns, and don't experience this problem. In fact, I have not heard of this problem on this design of saw. Alignment problems like he is describing are usually associated with "twin-tube" (my phrasing, I don't what the hell the manufacturers call it) trunnions.

You'll find the manual for your saw here

I would check the arbor bearings, part 4 in the exploded drawing (unlikely), and the pivot pin, part 13 in the exploded drawing (more likely), for excessive wear.

I hope this is more useful than the first response you got!
 
#5 ·
+1 on EE's comments. i own two emerson built 10" CI TSs and neither experience the noted problem. i'd try removing the blade and checking the arbor and the arbor flange for run out. i'd also replace the blade with a piece of 3/4" MDF (as it's stable, rigid and dead flat). recheck the measurements to ensure it isn't something weird about the blade. also, remember to lock the blade tilt lock lever (just above the elevation handle) prior to changing blade elevation. it won't take much blade tilt to have it looking like the blade is moving either towards or away from the miter slot as it's elevation is adjusted.
 
#6 ·
Thanks guys. That's a good idea to set the alignment at the most used height. If I can't figure anything out I'll just d reset the alignment to my most used height. I don't normally change the blade angle either so hopefully this will work out.
 
#7 ·
Along the lines of Purplev's suggestion to get it better than 0.005"....if you can't get the blade to miter slot alignment any closer than that, just tweak the final fractions by adjusting the fence parallel to the blade. If there's going to any deviation from perfect, it's better to have the tail of the fence fading away from the blade than than toward to avoid binding. Put a decent blade on it, and you should be fine.
 
#8 ·
to my most used height.

hopefully, you're aware that this is a potentially dangerous policy. freud recommends that the blade gullets just clear the top of the workpiece so sawdust can be ejected and not interfere with the cut. whenever material thickness changes, blade height should also change. pretty good comments here:

http://www.woodweb.com/knowledge_base/Table_Saw_Blade_Height_Above_Material.html
 
#9 ·
Last night I reset the alignment. I checked it at 1", 2" and 3" blade height and got an average of .012. Better than what it was (.-30-.040) It is a new blade but nothing fancy so tonight i'll check the blade runout. Other than that i'm happy because with the type of work that I do on it .012 really isn't going to make my work look bad.
 
#10 · (Edited by Moderator)
As knotscott pointed out, it's better to have the tail of the fence fading away from the blade than than toward to avoid binding. Mine is set up that way and I haven't suffered from kickback. But it ain't a cure! I still don't stand in the path of the blade.

I found the blade made a lot of difference. I originally had the old Craftsman multi-purpose blade that came with the saw, probably original. It had at least .025 to .030 runout. Diablo series blades highly recommended. I couldn't see any addition to runout from the blade with the Diablo blade.

Now, with the Diablo, I could actually measure the runout on my arbor - just under .005 near the teeth on the blade. If I get real ambitious someday, I may take a hone and get rid of that. There are plenty of sources on the Web showing how to true up the arbor.

At different heights of the blade, with a Diablo blade, I cannot measure any difference in the alignment on my 113 saw.
 
#12 ·
as I found out on my bosch 4100 contractor's saw.. the front tilting arbor pin assembly and bushing broke causing my table saw to be nonoperational because the blade would be nearly 1/8" closer to the fence in the rear than the front. Since I did not want to wear a sign that said "Kickbacks Welcomed" on my chest, I had to wait for the eReplacement parts to arrive a month later (darn backordered parts). It also gave me a good time to re-grease, spring clean, and re-wax everything.

Point being.. have you investigated all binding / friction points that align your blade?
 
#14 ·
try tightening the trunion bolts in a star pattern, gently snugging the bolts as you go. takes a bit of patience, but it is possible and, IMHO, worth the effort in terms of the safety a properly aligned blade provides.
 
#16 ·
@ajosephg I agree. Tonight I pulled the whole assembly out. I need to start over, inspect everything and while it's out I will take it to work and clean it real good. I found about a 1/4" of play in the arbor shaft. It moves in and out about a 1/4" so I can only assume the bearings are bad. I have to use my bearing puller to pull the pulley off the shaft so i'll do that tomorrow. The blade had .007" of runout. My ignorance says that's not a lot but i'm looking for .000"

The 2 motor bracket shafts (slides into the cradle assy) to adjust belt tension. How far into the cradle should they be?
 
#17 ·
I always aim for .003" or under.
This was learned from kelly mehler's table saw video.

What you're going through is why I will NEVER own a table mounted trunnion saw again, even is someone offered it to me for free.
 
#18 ·
@phlyers - if your saw is like mine, the belt tension is determined by the weight of the motor hanging off its support thingy. The motor bracket that I think you are talking about should be flush with the ends of the trunnion shafts.

If your blade has 0.007 runout (which is too much) you should check the arbor flange for runout. However, if the arbor bearings are bad that is a waste of time until you get the bearings fixed.

You mentioned in your original post that you are making the measurement with calipers. IMO you can not make accurate runout measurements using calipers - you need a dial indicator.

@Nitewalker - If I had known 25 years ago what I know now, I too would have never bought a contractor saw, but a cabinet saw. So - like many others I work at keeping it tuned up as well as possible knowing that at my age I don't have all that many years left.
 
#19 ·
Joe I used calipers to align the blade to the mitre slot and the dial indicator to check the blade.

Just a little update. I pulled the cradle out and took it all apart. The "in and out" play in the arbor assy was a missing spring washer according to the diagram. So I modified it so now there isn't any play. The bearings are fine. They aren't worn at all so hopefully that's all it was.
 
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