BT3000 tall rip fence

[nicer20]

Definitely making one especially for my small 7 1/4" blade since its kerf is thinner than the stock riving knife. Thanks for offering to help - will let you know how it goes & ping you if I get stuck.

NG

[nicer20]

mpc I liked the rip fence riding push block in the Woodsmith magazine article that you shared. I believe it satisfies all 3 requirements when pushing a narrow stock. So I will build one soon and share some pictures. Thanks for all the guidance and insights.

[nicer20]

@LCHIEN: My understanding is a riving knife should be thinner than the kerf but thicker than the blade. According to Diablo website the blade plate is 0.040" and the kerf is 0.059".
https://www.diablotools.com/products/D0724A

So I was thinking of using 0.050" thick material for making my riving knife. Am I wrong?

TIA,

NG

[LCHIEN]

Thank you for all the photos... now it all makes sense. I desperately need to make, or buy, a riving knife! I've had too many close calls using my saw without one.

Shark Guard (operated by the family of our long time, but now departed BT3 friend Lee Styron) still sells one made to order for BT3 and other saws.

https://www.thesharkguard.com/produc...and-splitters/

The knife pictured is not the BT3 model. Tell them the model saw, thickness desired

https://www.thesharkguard.com/how-to...ife-thickness/


a stainless steel 0.090" riving knife is $65 per the website

The Sharkguard blade guard designed to quickly clamp to the riving knife above is still available $180 for the BT3000 version with 2,5" dustport on top
https://www.thesharkguard.com/produc...tarted-it-all/

[mpc]

That's a good one. the best (safest) push sticks/push blocks do three things:
1: keep your hand well away from the blade and are easy to grip so your hand doesn't slip.
2: push the workpiece forwards in a positive, controlled manner. The little heel piece does that.
3: keeps the workpiece DOWN to the table. Table saw vibrations can make small cutoffs or small workpieces contact the upwards-moving rear blade teeth which is bad. My MDF push square example does not really satisfy this part... and my pictures show small workpieces that are quite likely to rattle around. The blade guard would provide a tiny bit of downwards force on them but a downwards pointed featherboard, attached to the rip fence, would be a smart idea.

Many plastic push sticks sold today have a small birds-mouth tip to hook over the workpiece. These push sticks are fairly long too so they satisfy things #1 and #2 but do little for #3. Changing the angle and size of the birds mouth can help a little bit. I created the wood one in my pics for that exact reason: the whole tool is more vertical when used and the bird mouth is longer on top than the heel part. But the Grr-Ripper is FAR more effective.

mpc

[LCHIEN]

if you are using 0.040 thick kerf blades then the 0.050" riving knife will jam!

Kerf of .059" and body of .040" will work OK with .050" riving knife.

[LCHIEN]

That tall fence is an equally valid way of doing it (tall fence and low strip fastened to the back with the clamp holes in the low strip). Saves having a thru hole in the fence but makes the rip fence more off center balance I suppose.

[LCHIEN]

Great post Loring, very well written and illustrated with your terrific photography.

I've not had a need for a tall rip fence, but if I ever do you've certainly showed the best way to do it; so, thanks.

I too like those HF Forstner bits and I've had my set for a few years now. Incredible buy.

CWS

I made a long skinny and short box for my rail extensions storage.
Usually such a box I cut and join all the sides and then cut the box in half - making it one kerf taller than desired. Then attach hinge and latches.
Cutting across the ends with the tall end waving in the air is hard to control on a 5" x 26" box against a 2" tall rip fence. Often when the pieces come loose they want to wander into the blade and it takes some wider gouges out of the joint. leaving a less than perfect closure line.
And that's when I use a tall rip fence.

[jlhumbert]

Okay, got a bunch of pics today. I'd already posted the low rip fence add-on; today's pics show why/how I use it.

Thank you for all the photos... now it all makes sense. I desperately need to make, or buy, a riving knife! I've had too many close calls using my saw without one.

[LCHIEN]

Yes, MPC is right about using the cut off splitter and also having it perfectly centered behind the blade. The mount needs to be perfectly centered, not the top. Then bend the top to line up perfectly parallel to the blade. Not as hard as it sounds but the base of the splitter/riving knife needs to be perfectly centered. Usually by eyeball.

pdf file for template for riving knife attached.
mild steel or even aluminum plate 0.063" to 0.090" wide (to fit behind a .093 thin kerf blade.
Not too hard to make yourself... I made one long ago. Let me know if you need some hints. Two sides are square 90 degrees so you have two sides already cut. if you get a rectangular plate. The two slots are not hard if you drill two holes and then cut upwards to meet them.
A jigsaw is all it takes with a metal cutting blade..

You don't need the top slots except to attach lee's blade guard if you have it.

[mpc]

In fact even without the crosscut fence extension, what was happening was that on wide crosscuts, my cuts were resulting in not being exactly 90 degrees. I was going nuts trying to find and adjust any play in the SMT which wasn't there. Then it struck me one day that as I cut and as the front part of the cut hits the knife and those nasty prowls, the board would slightly move to the left. No matter how tightly I tried holding the board against the miter fence. That was the root cause of it. Hence I removed the stock blade guard, riving knife assembly. Not an ideal scenario I confess but then I couldn't live with not perfect cuts - my OCD.

The stock riving knife mounts to two bolts... with a pile of shims between the knife and the aluminum block that holds the bolts. If you have the wrong number of shims in there, the knife won't be centered on the blade causing the problem you just described. The shims are small rectangles of metal, very thin, with two screw holes in them. So add/remove shims as necessary. From your description, it sounds like there are too many shims, pushing the knife to the left when viewed from the front of the saw.

Replacing the guard assembly, and/or installing a riving knife, is a bit of a pain thanks to those shims. They want to flop about and get in the way of inserting a new knife. What somebody on this forum recommended long ago was to cut up a soda can and make some tall shims - let them stick up about 3/8s to 1/2 inch above the mounting assembly. Make two like this. Then bend the parts sticking up outwards about 45 degrees - one bent left, one bent right - so the pair now forms a "V" shaped guide. Remove a few stock shims and insert this new pair, then slip the knife into the "V" and tighten the mounting nuts. See how the knife lines up with the blade - it should be centered. If not, add/subtract stock shim pieces as necessary. Doing this made re-installation of the factory guard or my riving knife FAR easier than the stock Ryobi setup.

Also verify the riving knife is flat as a pancake. Often they get twisted a little or bent sideways.

Oh, everybody knows they should use the blade guard and/or a riving knife... but many folks don't use them because of the nuisance factor. But the stock Ryobi anti-kickback pawls... I'm not sure anybody on this site likes them. The tips are rather sharp and tend to scratch the workpiece. Some folks file them so they aren't so sharp: instead of coming to a needle-like point, they get filed to be more like chisel tips facing backwards. That way they don't dig into the workpiece much but will still grab it firmly in the event of kickback. Other folks have removed them. Or hog-tied them into the raised position so they might as well be removed.

mpc

[nicer20]

Another simple/cheap push block is a plain old 2x4 or 2x6 board. Crosscut it to 6 to 12 inches long. Hold it on edge so it straddles the saw blade... the blade will make a shallow cut into it. So this is a "sacrificial" type of push block. Attaching a thin panel to the rear - with a screw or two - that hangs down about 1/8th to 1/4 inch gives a "heel" to hook over the trailing edge of the workpiece, making sure the workpiece and push block move together. Just make sure the screws are up high - well out of reach of the blade. Example shop built push blocks for various tools: Woodsmith Magazine simple push blocks

mpc

Here is my version of 2X6 push stick with a shoe (I think I saw something like this in some YouTube video):

[nicer20]

Okay, got a bunch of pics today. I'd already posted the low rip fence add-on; today's pics show why/how I use it. First up: what you get when trying to make a rip cut narrower than 1/2 inch on the stock BT3000 guard assembly with the stock rip fence:

................

edit: by the way, the black foot of the Grr-Ripper can be mounted to either side or left off entirely. Two small thumbscrews hold it to either side of the Grr-Ripper main body.
And the white thing on my stock blade guard is a glued-on bit of PVC pipe to hook up to my dust collector. I added a "Y" fitting at the stock BT3's dust port so I could run a smaller hose to the blade guard... I didn't bother hooking that up for these pictures.

edit #2: in one of your recent posts Nicer20, you showed crosscut fence extensions. To use those, you have to remove the stock blade guard and riving knife assembly, right? The stock knife is rather tall. Using a riving knife lower than the blade top would let your crosscut fence work while maintaining the safety of having a riving knife. Which is why I made my riving knife in the first place.

This is super useful. Can't thank you enough.

Looks like custom riving knife is in order. It also looks to me from your Grripper photos that with a custom riving knife, the L fence is redundant when used with Grriper. Unless of course, I missed something.

Yes as you pointed out in edit #2, I have removed the stock guard and knife altogether for the crosscut fence.

In fact even without the crosscut fence extension, what was happening was that on wide crosscuts, my cuts were resulting in not being exactly 90 degrees. I was going nuts trying to find and adjust any play in the SMT which wasn't there. Then it struck me one day that as I cut and as the front part of the cut hits the knife and those nasty prowls, the board would slightly move to the left. No matter how tightly I tried holding the board against the miter fence. That was the root cause of it. Hence I removed the stock blade guard, riving knife assembly. Not an ideal scenario I confess but then I couldn't live with not perfect cuts - my OCD.

Also, as I posted a few months ago in another thread, I switched to a 7 1/4" diablo blade. I am very happy with it. This one is even thinner kerf 0.059". The blade itself is 0.040" thick. Thanks for the McMaster catalog link. I think I will order an Aluminum 0.050" (+/- 0.004") 12 X 12 sheet to make the knife ((McMaster-Carr 89015K14).

Once again thanks for all the help.

NG

[LCHIEN]

Sacrificial push block!

same as post 42 in this thread with pictures https://www.sawdustzone.org/forum/di...you-made/page3

[mpc]

Another simple/cheap push block is a plain old 2x4 or 2x6 board. Crosscut it to 6 to 12 inches long. Hold it on edge so it straddles the saw blade... the blade will make a shallow cut into it. So this is a "sacrificial" type of push block. Attaching a thin panel to the rear - with a screw or two - that hangs down about 1/8th to 1/4 inch gives a "heel" to hook over the trailing edge of the workpiece, making sure the workpiece and push block move together. Just make sure the screws are up high - well out of reach of the blade. Example shop built push blocks for various tools: Woodsmith Magazine simple push blocks

mpc