Alignment & runout problems with the JET JPS-10TS

[Kevin Schlossberg]

Let me preface this by saying that I am a novice woodworker and I probably could have saved myself a world of grief by checking for proper alignment when purchasing the saw. Alas, at the time I didn't have the proper guages to do so (nor did I even realize I'd have to do this) so this has been a frustrating learning experience for me.

I've been trying to make 15 degree cuts on 2x4s using my Incra Miter 1000HD. I noticed that the 15 degrees weren't matching up top to bottom, which led me to believe that the saw blade was out of alignment. Woodcraft had a 15% off sale this weekend, so I headed over and purchased an A-LINE-IT alignment gauge. Lo and behold, the back of the blade was off from the front by +.015 - quick research here on the creek and on other sites told me that the blade should be perfectly parallel back to front, but .003" was "good enough" for most people. So, I endeavored to put it in alignment. Thus begins my tale of woe.

The JET Manual recommends that you measure the distance the trunions need to be moved, the flip the saw over, 'adjust' and then turn the saw back over. Yeah, right, like that was going to happen - I'd already installed a 52" capable Incra fence on the thing, along with a router table extension, there was no way I was going to rip all that off when I couldn't even figure out an accurate way to move the trunions precisely! So, it was time to get a low chair, bend over, and contort myself into getting the trusty old socket wrench (12mm bit) and included open ended wrench (13mm) over the nuts and bolts. Front and rear right sides of the trunions were a snap to get to. Front left was completely impossible to reach. Left rear took a great deal of contortion and the wrench kept slipping off. To make things worse, I needed a socket extension, so off to sears I went. When I got back, after a lot of sweating, cursing and repeated loosening / tightening of the three trunion bolts I could reach, I got the saw "good enough" - .003 deflection front to rear after 4 hours or so of frustration, measuring multiple areas of the blade.

Ok, now time to check and see if this held true with a different blade. Should be simple - press the arbor lock button on the top of the table, put included box wrench on arbor nut, twist and PING, arbor lock is stripped out. Ok, shouldn't be a problem, one of my open ended wrenches should get to the flats of the other side of the arbor... and they don't. Because they are all imperial. And too thick to fit down in there. Ok, no problem, broke out the calipers and measured: 17mm. Off to Home Depot, making sure to take along the included arbor wrench to make sure that the metric wrenches I was buying weren't too thick. HD wrenches are good to go, so I returned back to the shop, switched out the blade, cursed JET for making such a "feature" that broke so easily, tightened arbor nut, and... the saw was off true.


Ok, whatever. I'm getting pretty good at adjusting trunions now, so I true it up again. Switch out blades back to the factory one - pretty much in true now, just off by .005. I notice that when I'm tightening the trunions, it's going out of true by a couple .001ths. New HD wrenches make adjusting the trunions a lot easier since they are closed end and therefore aren't slipping off constantly.

Do some more research, read A-LINE-ITs web instructions saying I should have lowered the blade by 1/4" or so from max height and it makes a difference. Apparently max height torques the blade. Spend another hour or so with interruptions truing up the blade. Watch the A-LINE-IT gauge move .002 when tightening the left rear trunion repeatedly, so I compensate for that. At last, perfectly straight front to back! HALLELUJAH!

"Hey, maybe I should check the blade to see if it's at 90 degrees" - naturally it isn't. This is actually an easy fix - Unlock blade lock, and just back out the set screw in the table top. Squares align perfectly to it, no daylight visible between them and the blade.

For giggles I check the runout again and.... .015 difference between front and back. WTF. Then I get a moment of inspiration and try measuring the difference between when the blade lock is on and off. I turn the lock off and zero the A-LINE-IT. Front, off: 0.00. Front on: 0.07. Back off: .015 (guessing, at home so I don't have my notes). Back on: 0.027 :(

At this point I'm going to head back to woodcraft tomorrow and get a digital blade angle gauge. I'm going to make sure the blade is perpendicular first, then work the trunions one more time. I found this interesting thing from the people that make the A-LINE-IT gauge - http://in-lineindustries.com/saw_pals.html

I'm tempted to buy the thing and see if it works to make moving the trunions easier. I'm wishing I'd spent an extra 1500 on a cabinet saw at this point.

I'm also tempted not to use the blade lock again since it puts an unpredictable amount of torque onto the blade and causes it to go out of alignment to various degrees. Note to self - next time check alignment and such BEFORE installing accessories.

I could really use some feedback here.

[Mel Fulks]

Sorry you are having so much trouble.That kind of stuff can make recreational coal mining seem like a more enjoyable hobby. You mention 15 degree cuts,sometimes cutting angles can make something seem out of adjustment when it is not. Once when I was mitreing a large maple bar rail and could not get the cuts straight and flat or the angles right,I removed the sharp 80 tooth 12 inch blade and replaced it with a 60 tooth ,that fixed most of the problem. If you run into something like that again, try 90 degree cuts before deciding the saw needs adjusting. That's all I can suggest .

[Kevin Schlossberg]

What's really killing me here is that the blade lock takes the blade so far out of true. I'm probably going to just pick up a masterplate and use that to guage alignment in the near future, but the lock particularly irks me.

[Richard Wagner]

If it makes you feel any better, we have all have days like that in the shop. It is what makes this "hobby" so much fun.

You might want to consider tearing the whole thing down and rebuilding it from scratch (like it just came out of the box). No telling what you'd learn!

[Curt Harms]

I haven't used these - I didn't know about them when I had a contractor's style saw - but they get pretty good reviews. They're supposed to make alignment easy and help hold the settings. And the price is right.

http://in-lineindustries.com/saw_pals.html

[Andrew Pitonyak]

Be sure to clean the arbor and the nut so that there is nothing there to bring things out of alignment.

I have heard that this saw is a beast to align and also that if you can do it without tipping it over, that is fine; means I have read things by people that have done it that way.

Does any part of the saw hit anything when the saw is tilted? (like the motor hitting an outfeed table)

I have never used the Saw Pals, but some members here have them (for example, I think that Scott Spencer and Greg Koch use them)

[Paul Murphy]

Hi Kevin, we've all had those days. As a matter of fact I think I've had a day like that with my first cabinet saw. Truth is, even if the saw leaves the factory well aligned the shipping process can change some of your adjustments. I have had to realign my saw more than once over the years, just because of the realities of shop life. I once wacked the end of my 52" fence with my hip (man that smarts) and that twisted the table relative to the blade. The reality of todays cabinet saws are the trunions and/or table are mounted to a sheet metal cabinet...one good whack and it's out of alignment.

Anyway, time to take a step back and examine and understand the concept of what we are doing. Do a web search and find articles on the subject (both general alignment articles and manuals for aligning products), and read them for understanding of the concept, not for details on how to use what device. Here is one of many: ts-aligner.com/Tsman.pdf. Everyone learns in a different manner, and so an article/manual that works for me might not suit you.

OK, concepts:
1. To get the blade paralell to the slot we circle a spot on the blade with a pencil. Measure that "spot to slot" with the blade nearest the front of the saw, and then again with the spot rotated toward the back of the saw. We do that so blade/arbor runout is the same for both measurements, and that runout is not introduced as an error in our adjustment. After adjusting for paralell to slot, check thet the blade is centered in the insert so as not to touch when rotating. Check this at 45 degrees also.

2. We are not done when the blade is paralell to the slot at 90 degrees. Tilt the blade to 45, and check for paralell again. The concept here is that if the front of the table is shimmed incorrectly higher than the correctly adjusted back of the table (relative to the tilt axis), you are rotating the front trunion about a point that is not at the same elevation as the table. The more tilt, the more error. I cut shims from coke cans, sheet metal ductwork scraps, whatever is handy, and adjust...you might have to remove a factory washer/shim that is too thick, and reshim with thinner material. The concept is that both ends of the trunion must rotate about a point paralell to the slot and intersecting the surface of the table.

3. Paralell at 90 & 45 now, great! Are we done...probably not. We could have the table equally offset in elevation front and back, but how do we know? If the blade is paralell to the slot at 90, paralell to the slot at 45, but the fence scale isn't exactly the same for both, then we know the axis of rotation for the trunion is not at the surface of the table! Reshim front and back by equal amounts to correct.

Another place to read about alignment: woodgears.ca/delta_saw/alignment.html or Fine Woodworking #179 pg146 or americanwoodworker.com/blogs/tools/archive/2009/10/05/accurize-your-tablesaw.aspx