How do I realign the rip fence?

[Skip C]

Last weekend I decided to tune-up and realign the BT. I started with the rip fence, which has been slightly out of parallel with the back end slightly wider than the front end (handle end).

The manual is devoid of much instruction but says to use a carpenter sq against the blade to measure both the distance from the blade to the front of the fence and the distance from the blade to the back of the fence. Problem #1 is that the back of the fence can move about 1/8” to the left and to the right; so how do I measure? Where is the reference point for the back? Wherever I set the back, the back will move toward the blade when I lock the handle (when I lock the handle it is about parallel to the floor).

So now I have improved the alignment somewhat but at the expense of making the back of the fence closer to the blade than the front of the fence which should be a formula for more possibilities for kickback, correct?

Problem #2 is that the manual states that to align the fence, loosen the two top screws (which I did) but I’m not sure what they actually do. What are the top screws fastened to and how do they adjust the alignment? The parts picture in the manual is not much help.

Thanks for the help.

Skip

[crokett]

The back of the fence should never be closer to the blade than the front. At best you will get narrower stock than you want. At worst you will get kicback. I have mine adjusted so the back is about a playing card thickness further away from the blade. The top two screws let the fence move back and forth while the front handle is locked down.

Years ago I made a jig to help align the fence. I don't remember the BT3Central member who invented it, IIRC he lives in Florida. Anyway, my jig is a length of 2x2 with a 10 penny nail driven in about 6" from one end so about 1" nail is still sticking out. At the opposite end and face I glued two magnets about 6" apart. I raise the blade and stick the magnets to it. Then I slide the fence overs so the front is touching the nail. Then I flip the jig end for end and adjust the rear so I can slip a playing card or feeler guage between the fence and the nail head. Much easier than a framing square.

I use the same jig to align the SMT. I slide the SMT fence over so it just touches the nail. Then I flip the jig end for end and slide the table back. I adjust the table as necessary so it slides parallel to the blade back and forth.

The beauty of this jig is if the blade is not quite parallel to the rails it doesn't matter. You are adjusting the rip fence and SMT to run true to the blade.

The

[pelligrini]

There's a bunch of info in the articles section.

http://www.bt3central.com/index.php?page=articles

The link is sometimes hard to find, it's at the last of the new articles section of the main forum page.

Last time I aligned my fence I used an engineers square in between the blade and fence and tweaked the fence so it was parallel to the blade. I just slightly loosen the top screws to adjust the fence. They both go through the long aluminum fence extrusion into the aluminum casting. I've used dial calipers to do the alignment but I found it quicker using the heavy leg of the square. I like testing alignment using some scrap wood that will tearout easily, like some old luan. If I can rip from either side of the blade with no tearout I've got it parallel.

There's a lot of other methods, but I like the plywood test shows me I have it right.

[Skip C]

Thanks!

The manual says to lift the handle up before measuring, but you seem to imply that the handle shoudl be in the locked poistion when loosening the top screws and when adjusting the distance from blade to the back of the fence. Is that correct?

Skip

[pelligrini]

I don't lock the handle down tight when adjusting, but you need to when measuring. The way the fence locks it will pull the casting against the front rail for the alignment. It's one of the features that make the fence repeatably accurate. The BT fence is very accurate once set up properly.

[mpc]

Take a look at the rear of your fence, where it grips the aluminum rail. You'll see a small finger, about a centimeter wide, that just barely catches the lip of the rail. Make sure that finger actually goes UNDER the aluminum rail when you tighten down the fence handle. This should make the REAR of the fence grip the rail and be tight BEFORE the front/handle end locks down. If this finger goes above the aluminum rail, or "pushes" on the edge of the rail, the small black phillips screw in the end of the fence assembly (in the metal+plastic mechanism at the back end of the fence) needs to be adjusted. Sometimes the threaded rod inside the whole fence needs to be adjusted if this screw doesn't have enough range of motion to get the finger-to-aluminum-rail grip correct. I suggest this because, when properly adjusted, the rear of the BT3x fence should NOT have any side-to-side motion with the fence handle down. The BT3x fence is one of just a few table saw fence systems that clamps BOTH the rear and the front... nice. That 1/8th inch you talk about sounds like the back end of your fence isn't gripping properly to me, if I understood your post properly.

Once the back end of the fence grips tight - and grips before the front/handle end grips - you should be able to properly align (and use) the fence. The two black hex-head screws on the top of the fence, close to the handle, are what clamp the fence body to the handle assembly and allow you to align the fence body. Some folks have to file a bit of casting flashing off the handle casting though to get the fence aligned. Most folks also find Ryobi used a gorilla to tighten those hex-headed screws to the point where they strip out when folks need to remove them.

Basic blade-to-fence alignment:
Unplug the saw.
A jig folks have made to tune the fence:
* get a flat 1x4 board, about 10 inches long. Glue two small magnets into one long/thin edge so it'll stick to the saw blade (make sure the magnets clear the carbide blade tips)
* On the opposite thin (1-by) face, drive a skinny nail into the board so it's firm/strong with about an inch or more of nail shank sticking out. Cut the nail head off.

Use a marker pen to mark one of the blade teeth. This will be your reference - in case the blade itself is warped or has runout. Rotate the blade to put the marked tooth near the front of the saw. Put the jig against the blade, bring the front of the fence to the cut-off nail end, and clamp the fence. Move the marked blade tooth to the rear of the saw, flip the jig over so the nail is now at the back end of the saw... and see how the rear of the fence compares to the mail. Ideally the nail will be just a smidgen looser at the rear of the fence than at the front meaning the back of the fence is slightly further from the blade - like the playing card crokett described.

mpc

[mpc]

By the way, a carpenters square is useful for aligning the sliding miter table & its fence. For the main rip fence, either make the nail jig or just use the wider side of the carpenters fence between the blade and the rip fence. Just make sure the square never touches the blade teeth - it should ride against the body of the blade. The teeth are easily damaged but more importantly are not always a consistent size so they are lousy reference points.

Also, make sure the square really IS SQUARE. Many are close, but not quite, square. There is a trick with a punch and hammer to tweak them. Basically you punch near the corner, either on the inside of the "L" shape or near the outer corner, to expand or shrink the angle.

mpc

[Lonnie in Orlando]

Skip:

Here is the link to my "No Measure" alignment jig ...

http://www.bt3central.com/showpost.php?p=299413&postcount=1

FYI - I adjust the infeed side and the outfeed side of my rip fence to be the same distance from the blade.

In my opinion, adjusting the SMT to move parallel to the blade and adjusting the miter fence to be 90* to the blade is the most important step of the alignment process.

David:
Thanks for mentioning my jig.

- Lonnie

[crokett]

Use a marker pen to mark one of the blade teeth. This will be your reference - in case the blade itself is warped or has runout.

I thought I left a step out. Thanks for the reminder.

Lonnie, you are welcome - it is one of the simplest and most useful jigs I have.

[dbhost]

I recently had to do this when I had to replace the headpiece of my rip fence.

I do not know if I did it right, but I followed the advice of plenty of the magazine and woodworking book articles where I used a graduated engineers square to measure the distance from the blade carbide of a specific tooth at the front position where it goes into the table, and the rear position where it comes out... I double checked the measurement at the closest measurable points I could get to with the digital caliper, and I was .001 wider at the rear than the front. I guess if you look at it like a clock those were about 10:00 and 2:00...

[Skip C]

Thanks for all the help. I will go to work on this tonite! Skip

[LCHIEN]

my 2 cents:
The Two screws on top of the rip fence that are used to align... the hold the T-head on the rail to the fence. The holes in the top of the fence have some play, so when you loosen the screws the rail can swing a bit, wnough to make the alignment.

The secret to the alignment is in understanding how the rip fence locks. when the handle is part way locked down, then the T-head is clamped to the rail in front at two points. When the handle is pushed all the way down, then fence is locked to the rail in the back, a three-point locking system, where the front two lock first to square the head and then the back one locks to keep it from deflecting in use.

In order to set the square the front must be locked but the back must not be locked so that you can still swing the fence to the proper position. This requires careful modulation of the handle to where you feel the front locking but the rear is not yet locked.

How you check parallelism, with blocks, engineers square etc. is up to you but the above conditions of the front being locked and the rear unlocked when you set the screws to lock the relationship between the T-head and the fence is key.

[Black wallnut]

Loring gives the correct explaination of how the fence works. mpc has it backwards. The FRONT LOCKS FIRST, THE BACK LOCKS SECOND.

[Skip C]

OK, if I understand Loring and Mark, I should do the following:

Measure the front with the handle in a position that locks the front but not the back. Then adjust the back by loosening the top screws and moving the back to the same poistion and then tightening the screws. Correct?

I have not yet made an 'alignment tool'; I am just trying to understand the mechanics involed in adjusting the fence.

Again, thanks for all the hlep, Skip

[Black wallnut]

Yup Skip it really is that simple. However, and there is usually a however, many purposely toe out the back a few thousandths. Rather than measure if you know your wide leg of your framing square has parallel sides You can just set it up to the blade, set the rip fence to touch it front and back and you'll be done, this does not take into account any runout so add a drill bit as a spacer between the square and the blade at front, remove drill bit spin the blade so the same tooth is at the back of your throat plate opening and check clearance with the drill bit at back.