TS Blade alignment at 45

[keith jensen]

I did a quick search of SMC but couldn't find much. I'm trying to cut a 45 miter on the face of a 3 1/2" walnut board 1/2" thick. I started test cuts using some 3/4" pine to check my 45. I also used the digital angle gauge to check the 45 of the blade to the table. I made my fist test cuts and they were terrible! I could immediately tell something was wrong with the amount of resistance I was getting as I fed the board.

I put my dial indicator on the blade at 45 and found that front to back of the blade I am out by >.025"! When I checked it at 90 the blade was <.001" front to back.

I have a Delta contractors 2000 series (36-454) that I bought used.

What would cause the blade to be so out of parallel to the miter slot when I tilt it? Thanks for any help you can offer. I'm trying to make a fairly simple mitered jewelry box as a Christmas gift.

[keith micinski]

Where the trunions mount to the table is out of square. You might have to shim one of them.

[keith jensen]

Makes sense. I'm thinking I would have to shim it on the left rear given my readings on the dial indicator.

[keith micinski]

I've always thought it might be better to grind the high trunions then shim that way you only have to do it once and it is right.

[Cary Falk]

This is a common problem with contractor saws. The tilting of the blade racks the trunion due to the weight of the motor hanging from it. I am assuming your first measurement of .001" was before you tilted the blade. It will more than likely no go back to that measurement when you return to 909 degrees and you will have to redo the alignment.

[Anthony Whitesell]

Makes sense. I'm thinking I would have to shim it on the left rear given my readings on the dial indicator.

You either shim the rear or the front. Both the left and right sides at once. If you shim the rear down, the rear of the blades moves to the direction the blade tilts (that whole left-tilt/right-tilt thing still confuses me). If you shim the front, the the front of the blade moves to the direction the blade tilts. You still need to double check a 0/90 degrees afterwards. I usually set 0/90, then set 45, then set 0/90 again. I find the 45 easier to get stable (less bump and run technique) but takes longer as you have to figure out (via trial and error) the thickness of the shim(s).

[keith jensen]

Yep, fightin' with this thing on/off most of the day today. Had it perfect at 90 then off at 45. Perfect at 45 then off at 90. I tried to trig this out to get an idea of how thick my shims needed to be. When it was off by about .025" at 45 I added .012" shims. It didn't seem to have the effect I had hoped. I am going to start over without shims.

Once I started making all of these adjustments my dial indicator values really starting going wild. At one point I had .100" delta from front to rear!!!

Sure would be nice to have the manufacturing assembly prints...doubt Delta is just itching to hand those out though.

I think there might be something going on with the tie bars. I found online where someone talked with Delta about aligning the tie bars using a flat plate to make sure they are parallel. I'm wondering if there is some interaction going on that is making this much more difficult.

I'm really getting to know this machine now though! In the interest of time (24 Dec rapidly approaching) I'm hoping to get this ironed out.

Thanks for all of your input and keep the tips coming!

[glenn bradley]

I've always thought it might be better to grind the high trunions then shim that way you only have to do it once and it is right.

But if you goof, it is a lot harder to now grind the untouched areas to correct. I would shim. Also, being a contractor you will probably want to adjust it with the motor on and the belt under tension. My contractor alignment shifted enough to be seen by the naked eye, just watch while the motor weight was applied and removed :o.

Many folks go through great pains to align their saws at 90* and never follow through with the beveled positions. You will enjoy your saw more every time you use it by taking care of this alignment (it may not be correctable on your saw, the trunnion and motor assemblies on contractor saws many times cannot be fully corrected). It is a bit cumbersome with table mounted trunnions but worth the effort.

[Fred Belknap]

I went down the same road that you are going. The problem is the trunnion is weak and twists when the weight of the motor is put on it. I eventually got a cabinet saw and cured the problem. I still used the Delta contractor set at 90°, it runs smooth and does fine till the blade is tilted. I finally moved it to the barn for space reasons. I friend suggested that replacing the trunnion bolts with stronger bolts and lock washers, sounds like it might work but I haven't tried it. I liked the saw except for that but that is a big issue.
Fred

[Tom Veatch]

.... Also, being a contractor you will probably want to adjust it with the motor on and the belt under tension. ...

Just to clarify, you mean the motor installed and hanging from the belt, not the motor (turned) on (and running)?


...What would cause the blade to be so out of parallel to the miter slot when I tilt it? ....

Trunnion tilt axis not parallel with the table top. Anthony nailed the solution. Shim the top (cabinet saw) or trunnion (contractor saw).

Add shims to the front to move the front of the blade in the direction of blade tilt; add to the rear to move the rear of the blade in the direction of tilt.

[Mark Salomon]

Contractor saws are famous for this problem. I found that the best step by step advice was in a mid 2000 (2006?) article from American Woodworker about tuning a contractor saw. The article helps you identify the problem, and, depending on whether the rear of the blade toes in or out it, walks you through the correction process. Unfortunately, I had to install shims(washers) under the front trunnions so it was a lot of work. I also used the PALS adjusting nuts on the back which makes the rear trunnion adjustment much easier. I gave my saw away and got a cabinet saw shortly after I made the adjustment so I don't know whether it stays true. BTW, the problem is so common that Ian Kirby, in his book "The Accurate Tablesaw" recommends leaving the saw at 90 and using a sled for all bevel cuts.

[Fred Belknap]

Yea with a good blade and an up grade fence it is dandy saw except for the alignment thing. I would like to sell or get rid of mine someway, its cluttering up my barn. I got a T-2 fence on it and it is real nice. Maybe I will have a yard sale.:D
Fred

[keith micinski]

If you grind to much then you can shim it still. Most people don't have stock lying around for shimming so then you have to go get some feeler gauges, try and get the shims to stay in place while tightening and also not compressing to much when you tighten them down. I am sometime surprised at how much trouble people have with contractor saw trunions shifting around. I even own a 1960's craftsman saw that once set up holds it settings really well.

[Anthony Whitesell]

Ditto on that. I have a 1952 Craftsman that I didn't dare cut anything but 90s because it was sooooo far off at 45. Then I learned about the 'creek and a little bird told how to fix it up right. The saw cuts SWEET now.

[keith jensen]

Well,
I've made progress last night. The first thing I did was recheck my numbers from the previous attempt. Then I removed the shims and rechecked 90 and 45 numbers. I then placed a piece of flat plexiglass between the tie bars (removing the blade of course) and checked for flatness of the bars. There was some slight rocking so I loosened the tie bars and retorqued them. I then set the 90 to around .002". When I tilted it to 45 the front was high by .043" over the the diamter of the blade (say 8 1/2" since I measured inside of the teeth).

I started by shimming using .006" stock (I knew this was way too little but I wanted to take a baby step this time). Added .006" to both front trunnion mounts. Rechecked and set 90 and measured 45. This netted only about .003" improvement.

I then added a .070" steel washer which cut my .040" in about half to around .020" fore/aft on the blade.

I then added two more .006" shims per side which brought me to around .009" fore/aft on the blade.

When I have some time I am going to model a couple of lines in 3D space to see if my numbers make sense. Logically it makes sense that it would require at least double the shim thickness to alter my readings. SOH CAH TOA for the right angles my dial indicator makes with the blade. The sine of 45 is .707 for the vertical component of my dial indicator measurement. I'm going to expand this theory more...as time permits. This is probably all in the book Mark mentioned above.

At this point I ran out of time last night. I feel like I've made good progress this time but I'm curious if .088" shims seems like a lot to anyone other than me?!? I can definitely see where the weight of the motor is placing the majority of the downward vertical load on the rear of the table. It seems like I should see this though in the top of the table which I do not.

This really makes me wonder how well it was setup during production?

I must say that after I retorqued the tie bars, the lateral settings were much easier to get right. Most of the time between shim installation, I barely needed to adjust the lateral 90 degreee settings. Thanks again for all of the help with this!

[John Coloccia]

Have you checked the runout on the blade? I'm sure this isn't the problem but you should probably check this first before aligning off of it. If the blade is wobbling, you'll drive yourself nuts and never get it right. I HATE setting up tools, by the way. Many times I've considered just paying someone to come in and do it. It's definately my least favorite part of woodworking.