Can't get a square cross cut.

[trungdok]

Hi all,

I noticed that my cross cuts are not as square as I like it to be. So I brought out the manual to check and align the smt. For some reason, no matter how much I try, I could not get a clean square cut. Here are what I've done and results:

- Checked that fence is parallel to blade. They perfectly are and I'm very happy with any cut made using the fence.
- Using the Phil Thein's method (http://www.jpthien.com/3k.htm -- using a dial caliper instead of dial indicator, but the method is the same), checked that the smt base is parallel to the blade. They are.
- Using Phil Thein's method, square the miter fence to the blade as well as eliminating any play. - Cut a piece -- NOT SQUARE.
- Using an adjustable square (that I know is square using the scribe then flip method), check and re-square the miter fence to the blade again. It was square, indicating that Phil Thein's method worked, but I moved it around and re-square it.
- Cut a piece -- STILL IS NOT SQUARE.
- Repeat the last 4 steps a few times, then quit before I lost it.

The cuts tend to have an acute angle. At 6" from the base, there would be a gap roughly 1/32". I'm not sure what I'm doing wrong. Any thought is appreciated.

Thanks guys.

[Lonnie in Orlando]

trungdok -

Sounds like you have followed Phil's procedure to the letter.

Check again to make sure that you have removed any play in the Sliding Miter Table. Instructions in your manual.

Set a true straight edge on the miter fence to make sure that it is not warped.

Make sure that the quick-stop is touching the miter fence. The quick stop is micro-adjustable to tweek the final 90-deg setting.

Try a cross cut by pushing the miter fence and Sliding Miter Table with the knob that holds the miter fence to the SMT. This will reduce any torque applied to the workpiece that could move the miter fence or SMT out of alignment.

On my saw, I move crosscut workpieces by pushing the miter fence somewhere between the adjusting knob and the quick stop. This insures that the fence is pushed against the quick stop and is in the correct position.

If that doesn't improve the cut, then try another method of alignment. There are a lot of good methods to get a square cross cut. The BT3K sliding miter table throws a monkey wrench into the process. If the SMT does not run parallel to the blade, then it will pull the workpiece away from the blade. After the SMT is aligned parallel to the blade, then the miter fence must be aligned square to the path of the SMT.

I have been using a method for years that eliminates measurements to align the SMT, miter fence, and rip fence on my BT3000. There are probably better methods, but this one has worked for me.
> My "No-Measure Alignment"

After the SMT is aligned, use the "Five Cut Method" to square the miter fence. Also linked in my alignment procedure. Google "Five Cut Method" for other ways to do the 5-cut.
> Phil Bumbalough - Five Cut Method

Hundreds ways to skin the cat. Choose the one that you feel comfortable with.

- Lonnie

[Ian57]

You could try this

Hope I am I am not stating the obvious. Make sure the mitre guage is square to the mitre slot. Saw this on a u tube video but I am not able to find it atm.

[trungdok]

Lonnie, thanks for the link. I looked through your instructions quickly and one thing jumped out is that I didn't take into account of the high spot of the blade. I'm going to try that once I'm home

Ian57, I'm using the sliding miter table and not the slot. Thanks.

[LCHIEN]

are you using any other stuff, i.e. Ryobi Miter clamp?

[trungdok]

are you using any other stuff, i.e. Ryobi Miter clamp?

No. I just press the piece directly to the fence. I will have to try pressing it the way Lonnie stated.

[trungdok]

I think I figured out the problem - it's the fence shifting once locked down. I noticed that when I tighten the fence down, it shifts away from the square stop by a mm or 2. Not only that, but it also shifts a bit when I'm pushing it, depends upon how I push it. Now I have to be careful with how I tighten it, and how I push the miter table.

Does anyone else have this issue with their smt? How did you fix this so that you can tighten the fence down without having to worry?

Thanks,

[Lonnie in Orlando]

ERROR! ERROR! ERROR!

trungdok -

I was wrong when I described how I push my miter fence to send a workpiece through the blade ...

On my saw, I move crosscut workpieces by pushing the miter fence somewhere between the adjusting knob and the quick stop. This insures that the fence is pushed against the quick stop and is in the correct position.

CORRECTION:
> Insert the Locator PIn that slides on the bottom of the miter fence into the right hole in the Sliding Miter Table -- "Hole A"
> Flip up the Quick Stop and move the miter fence against it.
> Lock the Miter Fence Holder (Don't over tighten to crack or distort the Holder)
> To move the workpiece through the blade, hold the workpiece against the Miter Fence and push the Fence on the right side of the Miter Fence Holder. I sometimes hold the piece with both hands, one on each side of the Miter Fence Holder, and push more with my right hand or even pull back a little with my left hand. This will pivot the back of the left side of the Miter Fence against the Quick Stop.

> BT3K Diagram (Ray Girling)
> SMT Diagram (Ray Girling)

Also, inspect the Miter Fence Holder for cracks. If cracked, it could allow the miter fence to move. I had to replace mine.

Your Sliding Miter Table may have a crown in it from overtightening the Miter Fence Holder. This will prevent the Miter Fence Holder from clamping the Miter Fence to the SMT securely.

You may be able to file the crown smooth (?) Or you may be able to shim the Miter Fence Holder with metal duct tape to make it contact the SMT better.

I apologize for my error. Hope that you find and fix the cause of your problem.

- Lonnie

[trungdok]

Thanks Lonnie. I certainly had previously over tightened the fence. Is the crown underneath the miter table? I assume I would have to take the miter table off the base in order to see the crown.

[LCHIEN]

Thanks Lonnie. I certainly had previously over tightened the fence. Is the crown underneath the miter table? I assume I would have to take the miter table off the base in order to see the crown.

What Lonnie is trying to tell you is a crown is a convex table top (e.g. not flat as it should come from the factory) with a rise in the middle. With over tightening of the miter fence lock the bolt pulls up against the bottom of the SMT giving it a crown so that the miter fence only touches the SMT in the middle.


You can check for a crown with a straightedge from side to side. If the straightedge rocks much then you have some crown.

Generally its not usual for the miter fence to move simply by locking it down. Normally the pivot on the right or left and the locking knob give two points of anchor so it won't move. Not using the black pivot causes problems because you lose on anchor, then a crown will hurt you. Using the miter clamp (which I asked you about and you said no) has caused the fence to shift because the miter clamp pulls the workpiece to the fence which also pulls the workpiece forward as well.

Do you have my FAQ (see sig line below)?

[trungdok]

Thanks Loring, I see what you mean with the crown.

I have your FAQ and had been reading through it part by part. Lots of good information in there. I'll check my miter table and search through the FAQ for crowning. Thanks!

[trungdok]

Sure enough, there was a crown.

[LCHIEN]

i'm not sure how bad a very slight crown is, in terms of not making good cuts. Ideally its flat , and if it has a crown the work piece can rock and not be flat against the table where the blade is... I try and make sure that the workpiece is always flat on the table around the blade for cuts as a general rule.
The crown should not really affect the ability of the miter fence to lock in place if you have the two points i mentioned - the black pivot and the clamp knob.
do you have any way to measure the crown? Feeler gauges under one end... I hope its not more than a few thou... or maybe .020"

[cabinetman]

Any crown can have an effect. Flat is where it's at.

.

[Phil]

I replaced the plastic "locator pin" on the bottom of the miter gage. Seems to remove some slop. They're about $.80, so I bought 2.
Phil