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Contractor Saw - Align blade with, or without, Belt & Motor?

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Forum topic by EthanG posted 12-13-2018 04:17 PM 992 views 0 times favorited 20 replies Add to Favorites Watch
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EthanG

14 posts in 217 days


12-13-2018 04:17 PM

So, this seems obvious, but leads me to think something might be out of alignment.

I purchased an older Sears Craftsman ‘Professional,’ earlier this year. I’ve been working on getting it tuned up, but am running into a some problems. I recently couldn’t get it to tilt to 45, which lead me to tear apart, and clean, and lube all working parts. Now, after installing the PALS, I’m trying to get everything back to square.

I had aligned the blade, parallel to the miter slot, to 0.000, with the motor and belt off. This made it easier to get to the trunnion bolts and all that. Yet, after putting the motor and belt back on, I rechecked, and found that I was out by 0.010.

This is not satisfactory. I’m also trying to align the saw at 45, but can’t get the 90 square, even.

So, if the motor and belt are exerting enough force to take the blade out of alignment, what, if any, might the bigger problem be? After researching it, I’ve heard some of the following:
- Pulleys out of alignment.
- Bearings Shot
- Bearing too small for bearing housing.

Any, and all, help is appreciated. Woodworking has quickly turned into my favorite hobby, and my saw has been out of working condition for over a month…

Thanks,
-E

-- A clean shop is a safe shop.


20 replies so far

View jamsomito's profile

jamsomito

432 posts in 844 days


#1 posted 12-13-2018 05:33 PM

So a couple thoughts:

Yes, all of those could be contributing factors. Does your arbor wiggle at all if you try to stress the blade? If not, I doubt your bearings are too small. They should be nice and tight. They could possibly be shot, but you would notice it. I just replaced the bearings in my motor, plan to do the arbor bearings this summer. They’re definitely making noise and not flexing.

On a contractor saw, the motor is hanging directly off the tie rods that extend between and connect the trunions. It’s definitely making a rotational moment on the system, and possibly knocking the two out of alignment slightly. I would absolutely align with the motor mounted for this reason.

You could try sliding the pulley on the motor shaft as close to the motor housing as possible. This will bring the motor as close to the center of the mount as possible and maybe reduce the torque on the tie rods. Do make sure the pulleys are aligned too, although you will always have a force from the weight of the motor only being supported by the belt on one side. Just the nature of the beast that is the contractor saw. It’s kind of like your golf game. Don’t try to fix your swing when you’re on the course – use the stroke you brought for the day (i.e., mount the motor and align like that – it’s the best you can do).

Now when it comes time to tilt the blade, you can unearth another axis of alignment that might be out. Mine has this issue. I’m within 3 thousandths at 90, but off by almost 1/16” at 45. I bought an old back issue of the American Woodworker (#124, October 2006) that covered exactly how to fix this problem. Later I found Popular Woodworking just posted the whole dang article on their website for free… So I suggest you go check that out. It’s very thorough and explains how to get your bevel alignment perfect. https://www.popularwoodworking.com/techniques/accurize-your-tablesaw/

You’ll like those PALS. Good investment if you’re having alignment issues. Good luck.

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EthanG

14 posts in 217 days


#2 posted 12-13-2018 05:48 PM



https://www.popularwoodworking.com/techniques/accurize-your-tablesaw/

You ll like those PALS. Good investment if you re having alignment issues. Good luck.

- jamsomito

Yep, this article is what spurred me to go down this path. I will check the pulleys and see if they are out of alignment.

-- A clean shop is a safe shop.

View HokieKen's profile

HokieKen

9934 posts in 1556 days


#3 posted 12-13-2018 06:48 PM

If you put your indicator on the blade, can you move it .010 by hand? I’m going to assume yes. If the belt tension pulls it that far, then that play has to be in there. Tear it back down (sorry :-( ) and replace the arbor bearings. When in doubt about bearings, they’re easy to do and inexpensive, so just do them.

If it’s not the bearings, something is loose or cracked. Good luck!

-- Kenny, SW VA, Go Hokies!!!

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EthanG

14 posts in 217 days


#4 posted 12-13-2018 08:14 PM



If you put your indicator on the blade, can you move it .010 by hand? I m going to assume yes. If the belt tension pulls it that far, then that play has to be in there. Tear it back down (sorry :-( ) and replace the arbor bearings. When in doubt about bearings, they re easy to do and inexpensive, so just do them.

If it s not the bearings, something is loose or cracked. Good luck!

- HokieKen

Thank you. I just had it torn down, and I didn’t see any damage to the arbor, or its housing. The bearings didn’t seem to be making any sort of noise…

I’m going to take a closer look at everything, this weekend.

I’ll report back.

-- A clean shop is a safe shop.

View HokieKen's profile

HokieKen

9934 posts in 1556 days


#5 posted 12-13-2018 08:19 PM

Yeah, I would go that route too. First though, while you have it assembled, I would try to locate the source of the play. I have heard of things like the arbor bolts being too short when washers went missing and bottoming out in the threads without really snugging everything up. It’ll be easier to pull on the blade and feel/see flex if it’s something other than bearings while it’s all put together. Good luck man. Update us when you find the issue.

-- Kenny, SW VA, Go Hokies!!!

View johnstoneb's profile

johnstoneb

3115 posts in 2591 days


#6 posted 12-13-2018 08:53 PM

As HK says it is probably play in the arbor bearings. It may not be excessive. You have 2 bearings .005 play in each bearing may be just on the high side of manufacturing tolerances. You can replace the bearings but you may still have the same .010 movement. Bearings can be worn and not be noisy.

-- Bruce, Boise, ID

View jamsomito's profile

jamsomito

432 posts in 844 days


#7 posted 12-13-2018 08:54 PM

I had that issue on thin kerf blades. I ended up using one of my dado stack spacers between the blade and the removable arbor cap thingy… Not sure the term.

View HokieKen's profile

HokieKen

9934 posts in 1556 days


#8 posted 12-13-2018 09:00 PM



I had that issue on thin kerf blades. I ended up using one of my dado stack spacers between the blade and the removable arbor cap thingy… Not sure the term.

- jamsomito

I call it the arbor flange washer but not sure if that’s the correct term ;-) But that’s interesting since you and I have the same saw. I use thin kerf blades frequently and have never had any issue. I haven’t actually indicated it but never had any cut problems. Actually, I get better cuts with thin kerf blades. I wonder if at some point the arbor flange on yours was ground to be trued up… Something else to consider E.

-- Kenny, SW VA, Go Hokies!!!

View EthanG's profile

EthanG

14 posts in 217 days


#9 posted 12-15-2018 05:08 PM

Thanks all.

I Will certainly consider lathing the arbor flange, if it comes to it, and the washers that hold the blade on. But, I’d like to discuss the bearings, first.

To those who said the bearings might be worn.
- I took the belt off, and checked with a dial (digital) indicator. The vertical deflection that I could exert on the blade, via the arbor pulley, was 0.010, and the horizontal was about 0.001.

Why might there be a difference in directional deflection? If the bearings are worn, the deflection should be the same, no? I will state, it’s harder to put horizontal pressure on the arbor, as the blade then tends to spin. Could the arbor shaft be warped, or the bearing inserts worn?

At this point, I’m about ready to replace the bearing and pulleys, just for the hell of it. Or, buy a cabinet saw… if only I had the room for it.

Anyway, I fear the factory tolerances that John spoke of, even if I buy brand new bearings. If that’s the case with the new ones, I’ll have to just deal with what I have, and tune with the belt on, and take the 0.010 into account.

-- A clean shop is a safe shop.

View TheFridge's profile

TheFridge

10858 posts in 1904 days


#10 posted 12-15-2018 05:14 PM

New bearing on used equipment is a must for me.

And yes, you take your measurements under as normal of conditions as you can. Belt on and tuned.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View EthanG's profile

EthanG

14 posts in 217 days


#11 posted 12-15-2018 06:45 PM



New bearing on used equipment is a must for me.

And yes, you take your measurements under as normal of conditions as you can. Belt on and tuned.

- TheFridge

TheFridge, I guess that’s what I’ll do, either way. Do you have a suggestion for sourcing these parts? I prefer Amazon, but I don’t see Machined Pulleys there. The only place that I’ve seen ‘precision milled’ pulleys, is here:

http://www.in-lineindustries.com/products/pulleys-belts/

The bearings seem common enough, but I don’t know anything about the manufacturers. Do you have recommendations?

Thanks,
-E

-- A clean shop is a safe shop.

View MrRon's profile

MrRon

5566 posts in 3661 days


#12 posted 12-16-2018 06:49 PM

If you replace the bearings, get good bearings. Some of the cheap made in China bearings may actually be worse than the bearings you now have. Good bearings can cost you, so don’t buy cheap ones. Get well known name bearings like New Departure, Nice, SKF or some of the Japanese bearings.

Also make sure the bore, the bearing goes into is a tight fit, not loose.

View TheFridge's profile

TheFridge

10858 posts in 1904 days


#13 posted 12-16-2018 07:47 PM

I’d put it back together and run it before checking out machined pulleys. Unless I missed something and you needed them.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View HokieKen's profile

HokieKen

9934 posts in 1556 days


#14 posted 12-16-2018 08:07 PM

The bearing brands Mr Ron listed are good. Timken is as well.

I’m with Fridge, no need for precision machined pulleys on a contractor saw.

-- Kenny, SW VA, Go Hokies!!!

View EthanG's profile

EthanG

14 posts in 217 days


#15 posted 12-17-2018 02:21 PM

I’ve heard that the cast pulleys can be a bit deformed. If I have the thing apart, I’m not opposed to spending a few extra bucks on better pulleys, which will also cut down on vibration, and rubber belt memory issues.

As for bearings, I have a buddy that works for a bearing distribution company. I’ll run these brands by him, and see what he thinks.

Thanks, all. I’ll let you know when things come back together!

-- A clean shop is a safe shop.

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