Saw blade shifted over 1/4" on miter saw...???

[wakemeup]

I have a Hitachi C12RSH2 12" sliding compound miter saw.  I was using the saw for a few days and it was cutting great.  The saw sat in my locked garage with no one else entering or using.  It was not dropped or knocked over,  I went out to continue my project and on my first slide cut of a 2 by 6 the blade cut into the plastic table insert (See attached pic).  Also it hit the rear plastic guard like piece (See attached pic).  I measured the distance of the blade from a fixed point and it appears that the blade is about 1/4" shifted to the right, hence the cut into the table insert and the hitting of the guide.  I went through the owners manual and can't find any way to adjust this.  Anyone else experience this?  Is there a way to adjust this?  Any input would be greatly appreciated.  

[Coop]

Damn bud! I can only assume that you checked the Nut on the arbor to insure that it’s tight? 

[wakemeup]

18 minutes ago, Coop said:

Damn bud! I can only assume that you checked the Nut on the arbor to insure that it’s tight? 

Yes, I did.

[Coop]

Have you tried it at a different angle other than 90*? 

[Pixxture]

The numbers refer to a parts call out from ereplacementparts.com.  https://www.ereplacementparts.com/hitachi-c12rsh-sliding-dual-compound-miter-saw-parts-c-7927_13297_13307.html

I have the older version, C12RSH.  I also didn’t see anything that would easily account for a 1/4” shift.   Looks like you have already adjusted the green plastic table inserts (61, 62)  as much as possible.  The two parts that hold the slide pipes  (149, 166) are pretty solid.   It would be possible some part cracked and slid out of the hinge (173), unlikely but possible.  
 

my best guess, hope, is that you changed the blade and did not replace The inside blade washer (285, 287)

When u find it please let us know what u found.

[wakemeup]

50 minutes ago, Coop said:

Have you tried it at a different angle other than 90*? 

No, I haven’t tried that. Maybe tomorrow If I get some time. . 

[wakemeup]

35 minutes ago, Pixxture said:

The numbers refer to a parts call out from ereplacementparts.com.  https://www.ereplacementparts.com/hitachi-c12rsh-sliding-dual-compound-miter-saw-parts-c-7927_13297_13307.html

I have the older version, C12RSH.  I also didn’t see anything that would easily account for a 1/4” shift.   Looks like you have already adjusted the green plastic table inserts (61, 62)  as much as possible.  The two parts that hold the slide pipes  (149, 166) are pretty solid.   It would be possible some part cracked and slid out of the hinge (173), unlikely but possible.  
 

my best guess, hope, is that you changed the blade and did not replace The inside blade washer (285, 287)

When u find it please let us know what u found.

Thanks for the link to ereplacement. 
It actually happened with stock blade that I have never changed. The saw is almost new, barely used. I’m a low level intermediate woodworker at best.  That blade you see is a brand new blade. I changed it out out of desperation and it lines up exactly like the stock one. It’s almost like it needs a spacer on the arbor. 
Yes, I did move the green plastic inserts. It was actually worst. 
On the second picture you can see how far off the blade is when you line it up with the  handle that you change the cutting angle with. . 

[wakemeup]

1 hour ago, Pixxture said:

The numbers refer to a parts call out from ereplacementparts.com.  https://www.ereplacementparts.com/hitachi-c12rsh-sliding-dual-compound-miter-saw-parts-c-7927_13297_13307.html

I have the older version, C12RSH.  I also didn’t see anything that would easily account for a 1/4” shift.   Looks like you have already adjusted the green plastic table inserts (61, 62)  as much as possible.  The two parts that hold the slide pipes  (149, 166) are pretty solid.   It would be possible some part cracked and slid out of the hinge (173), unlikely but possible.  
 

my best guess, hope, is that you changed the blade and did not replace The inside blade washer (285, 287)

When u find it please let us know what u found.

I’m thinking maybe something going on with 292 or 300. When I get some time I’ll pull the cover off and take a look. Thanks again for the link. 

[Tpt life]

Have you rotated the blade? Any chance it warped? This pic is from the manual. Would not hurt to check. 

[Mark J]

Given that it's a new purchase, I always suggest a call to the company to discuss the problem.

[drzaius]

Given that the offset is consistent for the length of the slide travel, I'd say it is likely something is amiss with the washers on the arbor, as @Tpt life suggests.

How it got that way is the mystery. If it was in my shop, I'd blame the cats, as they are a couple of evil terrorists.

[pkinneb]

4 minutes ago, drzaius said:

Given that the offset is consistent for the length of the slide travel, I'd say it is likely something is amiss with the washers on the arbor, as @Tpt life suggests.

That would be where I would start as well.

[wakemeup]

I found it.  There is a pressed in collar/spacer on the upper slide arm that fell out of place.  In the pictures below it is freely moving on the arm but needs to be inside where I am pointing with the pic.  Its held in with a 3mm hex screw.  I briefly tried to get it back in from the rear but didn't have time.  I think it may have to go in from the front.  I also made a video so you can see the movement but couldn't attach it.   The whole arm wobbles.  Anyway, thanks for everyone's help.  I'll post something when I get it back in place.

[Tom King]

The company should send you replacement parts for the ones that got sliced up.  Looks to me like it was not properly assembled to start with.

[drzaius]

That'll do it. I guess the cats are off the hook.

[Mark J]

Not so fast on the cats. 

Someone had to loosen the set screw.

[pkinneb]

Wow glad you found it! I'm with Tom they need to provide some replacement parts for sure.

[Coop]

The collar/spacer was going to be my next suggestion. 

[wakemeup]

23 hours ago, Mark J said:

Not so fast on the cats. 

Someone had to loosen the set screw.

Haha!  I never knew it existed until I started looking at the arms for something.  Only thing I can think of is that I was doing a lot of slide cuts on 2  x 6’s and it just came loose and/or wasn’t tightened from the factory. 

[Mark J]

So you're thinking it was cats at the factory?

[drzaius]

1 hour ago, Mark J said:

So you're thinking it was cats at the factory?

That's my thought.

[Tommy Dee]

On 6/11/2020 at 10:18 AM, wakemeup said:

I found it.  There is a pressed in collar/spacer on the upper slide arm that fell out of place.  In the pictures below it is freely moving on the arm but needs to be inside where I am pointing with the pic.  Its held in with a 3mm hex screw.  I briefly tried to get it back in from the rear but didn't have time.  I think it may have to go in from the front.  I also made a video so you can see the movement but couldn't attach it.   The whole arm wobbles.  Anyway, thanks for everyone's help.  I'll post something when I get it back in place.

Have the same exact issue with mine. How’d you get it back in?

[drzaius]

9 hours ago, Tommy Dee said:

Have the same exact issue with mine. How’d you get it back in?

Unfortunately, the OP hasn't been here for 5 years, so they're unlikely to reply. Have you searched YouTube for an answer?

[zxc19]

That definitely sounds frustrating, especially when the saw was working perfectly before and hasn’t been moved or bumped. A 1/4" shift is pretty significant, so you're right to suspect something's off.

While the Hitachi C12RSH2 doesn’t have an obvious built-in lateral adjustment for the blade itself, there are a few possible causes and checks you can try:

1. Check the rail system and head mount:
Sometimes the sliding rail or the saw head assembly can loosen slightly at the mounting bolts or shift over time. Try checking the bolts that secure the saw arm to the rails and the motor housing—particularly around where the motor attaches to the pivot arm. A small shift there could cause the whole cutting arc to move laterally.

2. Look for wear or debris:
If there’s any sawdust, resin buildup, or even a damaged washer/spacer where the head pivots or slides, that could force it out of alignment. Blow everything out thoroughly and look for anything that’s cracked or out of place.

3. Fence and base alignment:
Double-check the fence and the table insert area—if the fence shifted or the insert wasn’t seated perfectly before, it could cause a collision with the blade when things move slightly out of spec. Also, make sure the fence isn’t bowed or dented near where the blade path passes.

4. Blade washer or arbor issues:
Make sure the blade is seated properly on the arbor and that the inner/outer washers are correctly installed and tight. If one of those isn’t snug, the blade can wobble or ride slightly off-center.

Unfortunately, no official adjustment mechanism exists to move the whole blade assembly left/right independently, so if you’ve ruled out debris, wear, or a loose component, it could be a warranty issue (if you're still covered).

If you want, checkout Sawblade.com. They have experts who'll be able to answer your questions.