# Finally aligned my Dewalt 7491 table saw



## AJPeacock (Jul 1, 2016)

Hi all,

Thought I'd share my alignment success story with the forum.

The only other table saw I've been around is a big Grizzly cabinet saw with huge wings/outfeed tables. That baby is easy, loosen a couple bolts, tap it with a dead blow and voila! Not so easy with these little contractor/portable saws.

I bought the Dewalt 7491rs about a month ago and other than adjusting the riving knife position (it was visibly too far right), I started using the saw exactly as it came out of the box. I'll be starting a couple projects soon that require a bit of precision so I thought I'd tune it up.

BTW: This table saw will be used with a sled to cut parts for hutches/cabinets/shelves … I use a Porter Cable circular saw and a shop built guide to break down my sheet goods.

During the alignment, I used a dial indicator attached to my miter gauge for all measurements (miter gauge shimmed with painters tape).

The front to back of the blade was out of alignment with the miter slots by more than 30 thousandths!

There are 4 bolts that hold the motor/blade assembly to the table, so I loosened 3 of them and barely loosened the fourth. I then realized the bevel lever needed to be loosened to allow free movement, but I needed to hold the bevel for measurement. I clamped a support between the frame and the lower right edge of the blade cover under the saw. I then loosened the zero degree stop, the motor/blade was free to move (or so I thought). After trying to align it several times with no progress, I realized the fabric that encloses the area for dust collection was too tight, holding it from moving freely. So I loosened the 4th bolt and slid the entire assembly to the right about 1/10" to give me some room to adjust. I positioned the assembly in the center of the slots front/rear and slightly tightened the 4 bolts. I then measured the alignment and was 100 thou out, but within about 10 minutes I had it down to .003 and then another 20 minutes I had it tightened and under .001 over the span of the blade.

To measure the alignment over a longer span, I replaced the blade with a narrow piece of 3/4" plywood. I was able to measure over an 11" span and got it aligned to around .0012", which I was really pleased with. Measuring the blade, it is under .001 front to back! The miter slots are not perfectly parallel, but pretty darn close for a portable saw (about .002" from parallel). The left slot is a touch wider than the right slot. I used the left slot to align the blade.

The fence was .007" wider at the back than the front. I adjusted it to be .001" wider at the rear.

The fence/miter wander in/out about .003" over the entire length of the fence, but amazingly are less than .001" out over the span of the blade.

So far I've only used the stock 24T blade that came with the saw, but I have a Forrest Woodworker II TK 40T on order that I'll use with the sled I'm putting together.

Overall I'm super pleased with the alignment, it took me 3 hours start to finish. I think I could do another one in an hour now that I know what to loosen, how to hold the motor still …

Here is the procedure I'd use if I had to do this again. 
0) Unplug saw and make dial indicator jig (just short piece of board with 1/4" hole to attach dial indicator), then clamp that board to miter gauge. Shim miter gauge with painters tape to limit slop.
1) raise blade fully up, then back off 1/2 turn. (set bevel at zero degrees)
2) remove blade and riving knife
3) Install 10×2x .75" plywood arm in place of blade (use for measurements). (5/8" hole a couple inches from one end)
4) Make initial measurements and write them down. Use a mark on the board to assure you are measuring from exactly same spot on board front and back. This keeps any warp in the board from affecting your readings.
5) remove 3 machine screws that hold the right hand side fabric to the table.
6) clamp a piece of ply between the frame and the lower blade gaurd, then loosen the bevel lever. 
7) remove crank from front of saw (makes access to zero adjust screw much much easier), don't drop the roll pin/washer. Loosen zero degree bevel stop, so it doesn't hinder movement.
8) Loosen the 4 bolts that hold the blade/motor assembly to the table (loosen just enough to be able to make the adjustments).
9) position motor/blade assembly in center of slots front/rear (you do this while laying under the saw).
10) Measure and adjust by tapping the mounting brackets with a long punch and dead blow hammer.
11) Tighten and re-assemble. (re-attach dust collection fabric under saw)
12) re-install blade
13) re-install crank.
14) Set bevel zero stop and 45 stop. (remove block between frame and motor assembly first)
15) Lower blade.
16) using same dial indicator setup, slide fence over saw blade and measure fence front/back distance from left miter slot.
17) Loosen slightly the 2 bolts holding the fence gear at rear of saw. tap the fence rail lightly with a small mallet until fence is aligned. Tighten the fence gear bolts.

Voila!

Sorry for the poor writing skills, I'm much better with numbers than words.

AJ


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## Johnnyg123 (Jul 28, 2019)

Thanks for the great tips. Just got the 7491 and was about to pull my remaining hair out tuning it until I saw your solution. The motor and assembly on my 7491 seem to have some play when you grab the left end of the motor and jiggle horizontally. Diving knife assembly moves with it. Also, the entire assembly can be flexed up and down a little but I suspect this is due to the plastic parts that are used. Does your 7491 have play or flexing as I described?


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## Sean_NZ (Nov 3, 2019)

I have just got a 7491 table saw, and the riving knife is not very well aligned (it is leaning to the left). From your experience aligning yours, i was hoping you could confirm a) what driver/bit do you use to loosen the adjustment screws, and b) turning those screws clockwise - does that tilt the knife to the left, or to the right?

thanks very much for your help!
Sean


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## AJPeacock (Jul 1, 2016)

> I have just got a 7491 table saw, and the riving knife is not very well aligned (it is leaning to the left). From your experience aligning yours, i was hoping you could confirm a) what driver/bit do you use to loosen the adjustment screws, and b) turning those screws clockwise - does that tilt the knife to the left, or to the right?
> 
> thanks very much for your help!
> Sean
> ...


Honestly I can't remember which ones turned which way. I do remember that they were opposite how I thought they should be!

AJ


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## Sean_NZ (Nov 3, 2019)

Thank you! That is helpful in itself.  I don't suppose you recall whether the adjustments were done with hex keys or with a screw driver?


> Honestly I can t remember which ones turned which way. I do remember that they were opposite how I thought they should be!
> 
> AJ
> 
> - AJPeacock


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## AJPeacock (Jul 1, 2016)

> Thank you! That is helpful in itself.  I don t suppose you recall whether the adjustments were done with hex keys or with a screw driver?
> 
> Honestly I can t remember which ones turned which way. I do remember that they were opposite how I thought they should be!
> 
> ...


I recall a hex key, I think you loosen one and the set the angle/distance with 2 others??

AJ


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## Sean_NZ (Nov 3, 2019)

thanks!

Yes, the manual has fairly vague instructions on how to do it, (loosen one, adjust the others, tighten the loosened one), but just not with what, or in which direction. I tried to find a hex key to fit, but was missing a few in my set, which didn't help 

I really appreciate your assistance
cheers
Sean


> Thank you! That is helpful in itself.  I don t suppose you recall whether the adjustments were done with hex keys or with a screw driver?
> 
> Honestly I can t remember which ones turned which way. I do remember that they were opposite how I thought they should be!
> 
> ...


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## TravisN (Jan 15, 2019)

I have the 7480 and use it basically out of the box. It's been incredibly difficult to find tuning instructions. I might try some of your tips, assuming a basic similarity between the two models. Then again, this gives me a nice excuse for my poor woodworking results


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## Dadan (May 13, 2020)

Yeah thx. In having the same problem with mine. I have mine hooked up in my home shop so it's not easy to get to. I don't want to unbolt it because I have it hooked up to an external fence and dust collector. I've tried the two bolts in the back with no luck. Just stayed the same. I've had the saw for about ten years so it's definitely an older model but what you're describing sounds the same. Hoping that releasing the miter will do the trick. Waiting till this weekend to pull the saw out if I couldn't fix it. Can't really see what's going on. My math is way better than my writing too. Haha


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## JetLaggedChef (Aug 3, 2020)

I made a video about how to align the riving knife since the manual that came with the saw is wrong and I couldn't find a solution online.


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## LJRay (Apr 12, 2014)

I just purchased a 7491RS and had a bear of a time getting the riving knife aligned. I almost stripped out one of the lock screws just trying to loosen it. I was only successful at doing so after loosing the other lock screw. The instructions say to only loosen the lock screws and then adjust the set screws as needed. They don't mention that the lock screws do have an affect on the knife alignment. Only after loosening both lock screws considerably was I able to get the set screws adjusted appropriately.

FYI. 
The diagram on page 7 showed one of the three set screw as being on top, which is incorrect. The top is a pin - the third set screw is on the bottom. 
I used a 4mm hex key for the lock screws and 2.5mm for the set screw. (at least i think the very small writing on the latter said 2.5)
I also removed three of the star bit screws holding the the fabric dust shield so I could see better and reach in through that way to assist in aligning the knife


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## RomanS (Aug 19, 2020)

I got my riving knife misaligned as well. JLRay thank you for your note, it helped me solve the problem. I just wanted to expand on it to help others after spending 2 hours on this process.

So here is how I did it:

1. Unscrew two or three screws that hold the vertical black plastic plate covering the right side of the blade below the surface. That allows you to conveniently access to adjustment screws later 
2. As JLRay says, use star head to unscrew 3 screws to that hold the black fabric.
3. Instructions say you have to raise the blade all the way up first. This is not correct. When you raise it all the way up you can't really get to the adjustment screw. So, lower the blade to about 1/2 or all the way in.
4. Always loosen the two big screws first. I think it is hex 5/32. They are very tight from factory, I used my electric wrench to loosen them and then did by hand. Small ones are hex 3/32 I think.

About the screws. The way they work is this: big screws push the plate that keeps the knife *into* the table (if you are standing in front of the saw (normal working position) they push the plate and the knife to the *left*). The small screws act as stoppers, sort of allowing you to control how much to the left the plate will go until small screw touches the left side and stops the plate (and thus the knife). I.e. if you screw *in* the small screw it will increase the gap and will not let the plate go too close to the left (i.e. you use clockwise to make the knife go right). If you unscrew the small screw then it will allow the plate to go further to the left. But there are two small screws on the same level! In addition to being general distance stoppers they allow you to correct situation when your knife is not fully parallel to the blade (mine was not).

The bottom small screw works for vertical alignment. If you screw it all way in, it will make the top of the knife go left. If you unscrew it a bit, it will allow the top of the knife to become vertical and then go right.

So you continuously play with small screws and the large ones. Takes multiple cycles, because once you think you got small ones perfectly, when you tighten larges ones it shifts things again. So you loosen large ones, adjust small ones in anticipation of the move by the large ones, and try again. When doing all this, you have to periodically raise and lower the blade to make sure it is well aligned left/right and vertically on all depths. 

So again, bottom small screw is for making the top of the knife be vertical (mine was leaning to the right), and the other two small screws are for controlling that the knife is fully in line with the blade, and that it is sitting strictly in the middle of the blade.

Good luck folks.


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## kabuhr (Oct 31, 2020)

AJPeacock, thanks for sharing this! After unpacking and assembling my 7491RS, I found the bevel stuck at around 10 degrees and unable to zero. I came to find it had been packed and shipped with the cord tightly jammed between the saw housing and the yellow plastic tool/cord storage bracket. Possibly as a result, the blade was misaligned by almost 1/16" front to back, but-maybe even worse to my mind-with the bevel zeroed, the stop cam didn't reach far enough to lock in the zero setting. (In practice, maybe not a huge deal, but just knowing it couldn't be properly aligned in that respect would have driven me nuts.)

Since the instructions only mentioned loosening and adjusting the rear bracket to the align the blade, I probably wouldn't have realized (or been brave enough) to loosen and adjust the front bracket, too. After reading your post, I was able to adjust the whole housing to fix both the alignment and engage the bevel stop cam properly.


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## clay451 (Oct 9, 2020)

Just got the saw and I'm going through this process. One issue that's kind of throwing me off is my riving knife jiggles right out of the box. I slightly tightened the locking screws (larger screws) as much as I felt comfortable with. They were already pretty tight and I don't want to push it any farther to cause any striping. The riving knife still jiggles, this can't be normal right? I mean it move pretty easily right and left of the blade. I did notice if I were to move the riving knife up a little bit, it's more stable but then it seem to far from the blade. If anyone can clear this up that would be awesome. For more clarity on that, there's a line on the riving knife below all the dimensions of the knife, when I place that line even with the top of the riving knife mounting bracket it jiggles a lot (when I push the riving knife all the way in). Then if I pull the riving knife out to where that line is almost even with the table top, it's more stable, yet creates a large gap between the knife and the blade. Any info on this issue and if it's normal for the knife to giggle (which I don't think it is) would be great. And any info on where I need to align that marking on the knife would be awesome as well.


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## tagit446 (Oct 12, 2021)

@clay451, I know this is an old thread and I don't know if you were able to figure out why your riving knife has some jiggle to it but I just spent some time aligning my riving blade (DeWalt 7491) and I had the some problem as you which also made it hard to adjust the knife.

Here is what I found by accident. My riving knife was offset to the left of the blade and also appeared twisted from the front of the knife to the back of the knife. I fiddled around trying to adjust it and could only get it close. I finally decided the fasted way to get this adjusted was to remove the two large screws completely so that I could remove the entire riving knife mount allowing me to see the 3 set screws(more on that below). While removing the 2 large screws I noticed a good amount of tension pushing against the mounting block. Once the mount was removed, I could see the tension was caused by a lever behind the block that is used to remove the riving knife. This lever is cable operated and also attached to the riving blade release handle. The issue is that the cable is out of adjustment causing to much tension against the riving blade mount.

The solution to fix the jiggly riving knife is to back off the adjustment nuts all the way on the cable, make sure the cable has slack in it taking all the tension from the lever behind the riving knife mounting block, then pull the cable until the slack is gone and lock down the nuts.

I actually did this with the riving knife mounting block removed. I did however do the cable tightening adjustment once the riving blade was properly adjusted.

If anyone is having issues getting the riving knife adjusted, I found it was easier to just remove the 2 large screws, then the mounting block. Then adjust all 3 set screws below the block surface, reinstall the mounting block, fully tighten the 2 large screws, then tighten all 3 set screws. This gets everything flush. Your riving knife will likely be offset to the left of the blade now.

Now loosen the 2 large screws and tighten each of the 3 set screws by equal amounts. Tightening the 3 set screws will force the riving knife to the right. I did half turns of each at a time. I think I ended up giving each 1 a full turn and a 1/4. Finish by tightening the 2 large screws.

If you loosen the 2 large screws and your riving knife has tension pushing it to the right as you loosen them, then your release cable is out of adjustment.


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## ColoradoBrian (Dec 15, 2020)

Thank you for bumping this thread! I missed it first time around. I feel exonerated. I bought a 7591 and the crap-tastic quality control has been one headache after another until… well, it's still a headache. This month it was making a sled work with miter slots that are inconsistent in width. That was all kinds of fun but I finally got it to work. Sorta.

Some time ago I posted a '8 problems & 8 solutions' thread for my saw on another forum I used to frequent. Let me know if you find it helpful & I'll re-post it here. But I'll make it 9 problems & 9 solutions for my sled woes.

I still wonder how my life would have turned out if I'd bought the Bosch. I can't wait for the day I can buy a proper contractor saw.


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## thampyshany (2 mo ago)

tagit446 said:


> @clay451, I know this is an old thread and I don't know if you were able to figure out why your riving knife has some jiggle to it but I just spent some time aligning my riving blade (DeWalt 7491) and I had the some problem as you which also made it hard to adjust the knife. Here is what I found by accident. My riving knife was offset to the left of the blade and also appeared twisted from the front of the knife to the back of the knife. I fiddled around trying to adjust it and could only get it close. I finally decided the fasted way to get this adjusted was to remove the two large screws completely so that I could remove the entire riving knife mount allowing me to see the 3 set screws(more on that below). While removing the 2 large screws I noticed a good amount of tension pushing against the mounting block. Once the mount was removed, I could see the tension was caused by a lever behind the block that is used to remove the riving knife. This lever is cable operated and also attached to the riving blade release handle. The issue is that the cable is out of adjustment causing to much tension against the riving blade mount. The solution to fix the jiggly riving knife is to back off the adjustment nuts all the way on the cable, make sure the cable has slack in it taking all the tension from the lever behind the riving knife mounting block, then pull the cable until the slack is gone and lock down the nuts. I actually did this with the riving knife mounting block removed. I did however do the cable tightening adjustment once the riving blade was properly adjusted. If anyone is having issues getting the riving knife adjusted, I found it was easier to just remove the 2 large screws, then the mounting block. Then adjust all 3 set screws below the block surface, reinstall the mounting block, fully tighten the 2 large screws, then tighten all 3 set screws. This gets everything flush. Your riving knife will likely be offset to the left of the blade now. Now loosen the 2 large screws and tighten each of the 3 set screws by equal amounts. Tightening the 3 set screws will force the riving knife to the right. I did half turns of each at a time. I think I ended up giving each 1 a full turn and a 1/4. Finish by tightening the 2 large screws. If you loosen the 2 large screws and your riving knife has tension pushing it to the right as you loosen them, then your release cable is out of adjustment.


 Thanks a lot ! This blade was out of line with the knife .. ( out of the box DWE 7491 ) as the sled I made had a tighter moment ! Your above instructions were very clear to get this issue fixed completely.. for days I sat on YouTube for a remedy but was in vain ! Thanks again


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## thampyshany (2 mo ago)

Quite Surprised with DeWalt DWE 7491 brand New ( Out of the Box ) requires Alignment at several fronts to be a Perfect Square .. but the most Confusing part was knife with blade .. resolved after reading the post here ! Now 7491 is in Square at All fronts ! Ready to Explore the New Machine! Thanks a lot!!


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