Trouble in the Making

JPG · Post by **JPG** » Mon Oct 19, 2009 2:49 pm

dusty wrote:It does not clamp to the fence. The hook is the only thing working other than gravity.

The pictures associated with post #3 in the following thread will (I think) answer all your other questions. No, there is one other. Those are not t-nuts they are threaded inserts (almost the same thing).

1) I was asking about the sliding stop on the fence(that which snagged the board on the back stroke).

2) WHAT 'following thread'???

3) I am assuming the pix of a similar device with a white knob on another thread(that the one that follows??? )with an angle bracket screwed to the back of the 'stop' face and the knob that screws into the sliding t track 'nut'. i.e. the clamping is done in the top t track with the knob with integral bolt.

reible · Post by **reible** » Mon Oct 19, 2009 3:10 pm

I think I'll print this out and paste in my PTWFE in the safety section.

Hazardous actions are 'ok' as long as recognized and adequate measures taken!

D
Ed

dusty · Post by **dusty** » Mon Oct 19, 2009 4:08 pm

JPG40504 wrote:1) I was asking about the sliding stop on the fence(that which snagged the board on the back stroke).

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

3) I am assuming the pix of a similar device with a white knob on another thread(that the one that follows??? )with an angle bracket screwed to the back of the 'stop' face and the knob that screws into the sliding t track 'nut'. i.e. the clamping is done in the top t track with the knob with integral bolt.

Yes, it rides on the fence and is secured to the fence using a Shopsmith t-nut and the knob. Those are t-nuts that secure the angle to the stop board as well (the cheap, drive it in with a hammer type).

JPG · Post by **JPG** » Mon Oct 19, 2009 4:16 pm

dusty wrote:Yes, it rides on the fence and is secured to the fence using a Shopsmith t-nut and the knob. Those are t-nuts that secure the angle to the stop board as well (the cheap, drive it in with a hammer type).

Thank You for the elucidation!

JPG · Post by **JPG** » Mon Oct 19, 2009 4:19 pm

reible wrote:I think I'll print this out and paste in my PTWFE in the safety section.

Hazardous actions are 'ok' as long as recognized and adequate measures taken!D
Ed

Just be sure to include a statement to the effect that one should do so ONLY if NO safer alternative is feasible. :>)

charlese · Post by **charlese** » Mon Oct 19, 2009 10:40 pm

Wow! - Let me try to explain that this was not the cause of anything mechanical. It was truly operator error!:eek:

Rip fence and block -
The rip fence and block did not cause the error! The placement of the stop block did not cause the error! Had the workpiece not been pulled back into a spinning blade these mechanical things would have had no effect. The fence itself or the block had no effect on the error. In fact, it is a recognized practice to use a rip fence as a base for any non-thru cut. The block could have been placed anywhere along the fence, so long as part of it was in front of the blade. Actually, the block is a bit of over-kill for dados or grooves. It is easier and safer to use just the fence. Placement of the block is critical for thru cuts, but not non-thru cuts.

Out feed table -
Actually, an out-feed table is not needed as the clamp with the miter gauge would hold the board on the table after it has cleared the saw. All one needs to do is turn off the saw then use that hand to go after the board. O.K.! Yes if there were an outfeed table, the board would be easier to get hold of to bring back, But still, it is not a safe practice to reach across a spinning saw to do anything!

Reason why pull-back is BAD -
Here's the reason not to pull a board back through the spinning saw. - - With a miter gauge, the clamp or the workman's hands hold the board tight to the pushing surface. If the workpiece is pulled back, the part of the piece far away from the saw can, and will, drag on the surface. This drag WILL cause the workpiece to twist so the back part of the freshly cut surface is forced into the back of the spinning blade. This will happen on a non-thru cut as well a a thru cut! This is another reason to use the Shopsmith Upper saw guard and splitter with anti-kickback pawls. It becomes impossible to pull a board back past a spinning blade when it is used.

P.S. - This would also be true with a crosscut sled, if there is anything that can catch or drag the far end of the workpiece. Perhaps it is the use of crosscut sleds that helps develop the bad habit of pulling a board back past a spinning blade.

reible · Post by **reible** » Mon Oct 19, 2009 11:39 pm

After reading Chucks comments I have to post a disagreement. (Sorry Chuck, nothing personal but I have a different view point on this)

The use of both the miter gauge and the rip fence at the same time is a bad practice.

You have two controlling surfaces rather then one...

If the miter gauge is not right on 90 degrees things can get to a point that the wood can toggle between square to the miter gauge or square to the rig fence, since it can't do both at the same time you are left with a bad situation.

It is the same thing with the rip fence being just slightly off... some where along the cut it could be forcing the wood into the rip fence (which will not move and it will likely move the work piece) and will resulting in either a less then wonderful cut and at worst case cause a kick back.

It is very difficult to force the wood into the rip fence and against the miter gauge at the same time especially if thing are not total square (that includes the board edge that was cut and now against the rip fence). In a perfect world with perfect alignment and perfect cuts go for it... those that are struggling to get a minimal alignment pick one way or the other.

If you look at it as the fence and miter gauge having to be almost in prefect alignment for this to work it become obvious that to have one or the other perfect is unlikely but having them both perfect is even more unlikely (that is blade to rip fence parallel and miter gauge to blade at 90 degrees).

Those of you who have been working with router know that this was a major flaw in the early systems and now the practice has been replaced with sleds.... or with going to hand held routers and jigs.

So if the block were in the correct position then during the cuts the wood would be made with only contact to the miter gauge. This is certainly the way a less wide piece would be done and I'm sure you have seen Norm do that a lot of times...

If the wood were to be slid along the rip fence that would also be OK. On wider piece this might be a better way but again you might want to think about how much support you have against the fence at the beginning and ending of the cut. If the wood is not stable against the fence then it is not a good way to go. Without going back to check I'd say this only applies to boards with a width of say about 8".

OK now you have my opinion on that.

As far as pulling a workpiece back over a spinning blade in most case that is a no no. Are there exceptions? Sure. Take the incra and jointech systems where they have integrated the systems and it is designed to let you pull back the workpiece back over the spinning router bit... When your nibbling wood away rather then using a dado setup... for things like the example Dusty gave us that is problem waiting to happen.

Ed

dusty · Post by **dusty** » Tue Oct 20, 2009 6:22 am

curiousgeorge wrote:Am I wrong? Or isn't the block supposed to be set up to where the piece being cut has left contact with the block before contacting the blade. It looks to me, with the setup in the first picture, that the board is still half on the block when it contacts the blade and that constitutes using the miter and fence at the same time. A real no no. If the block had been set up correctly the piece would have already cleared the blade, when retracting, before contacting the block again. But then, I have been wrong before....

You are correct. One should never set the rip fence as I did while using the miter gauge to move the piece. That was suppose to be the purpose of the stop block. I was doing multiple pieces and trying not to "measure and mark" every one.

It worked fine until I pulled that particular piece back to me. I needed the outfeed table so that the piece could just lay there after it had cleared the blade. I had not attached the outfeed table and did not want to stop work to do so. After all, I only had six pieces to cut.

The outfeed table is now modified so that it can be attached even after the Shopsmith has been setup with all the rail tubes in place.

BTW, I use a router a lot for dadoes but there are some cases where the router is not efficient. When I am doing multiples, I will continue to use the table saw for dadoes.

charlese · Post by **charlese** » Tue Oct 20, 2009 2:05 pm

reible wrote:After reading Chucks comments I have to post a disagreement. (Sorry Chuck, nothing personal but I have a different view point on this)

The use of both the miter gauge and the rip fence at the same time is a bad practice.

You have two controlling surfaces rather then one...

If the miter gauge is not right on 90 degrees things can get to a point that the wood can toggle between square to the miter gauge or square to the rig fence, since it can't do both at the same time you are left with a bad situation.

It is the same thing with the rip fence being just slightly off... some where along the cut it could be forcing the wood into the rip fence (which will not move and it will likely move the work piece) and will resulting in either a less then wonderful cut and at worst case cause a kick back....

...It is very difficult to force the wood into the rip fence and against the miter gauge at the same time especially if thing are not total square (that includes the board edge that was cut and now against the rip fence).
Ed

I appreciate your disagreement Ed! Thanks! That's what the forum is for!

I'm backing up on my earlier post. You have very clearly described the reasons for not using both a miter gauge and rip fence at the same time. Your good discussion and points should be recognized and remembered by all woodworkers.

To further clarify my earlier post, I was speaking of NON-THRU cuts only. Yes, one should make sure the wood is not forced into the fence while controlling the pass with the miter gauge.

Yes, the fence must be very closely aligned to the miter slot. If aligned away from the miter slot, There would be no problem, it would be similar to using a block. If aligned toward the miter slot, the non-thru cut would be slightly canted at an oblique angle. I just don't believe there would be a kick back. Only (as you say) a less than wonderful cut.

That said, I will retract my earlier thoughts about a block being overkill! A block is a good idea for accurate, spuare dados.

Also, in the way of retraction, I realized I was thinking of dados (as shown in Dusty's photos) being made fairly close to the end of a board that would be riding on the fence. I was not thinking of trying to use a rip fence on the end of a board that is farthest from the saw.

All that "eating crow" does not lessen the warning that pulling a board back over a spinning blade, when using a miter gauge, is very dangerous and should never be done! (I added "when using a miter gauge" because a pull back may be acceptible when using sleds.)

JPG · Post by **JPG** » Tue Oct 20, 2009 2:56 pm

"(I added "when using a miter gauge" because a pull back may be acceptible when using sleds.)" quote from Chuck above

Key word here is MAY The hazard still persists if the workpiece is NOT held tight against the sled fence(similar to workpiece moving away from the miter gauge face.) The sled DOES eliminate the drag against the table on the workpiece thus reducing the 'potential of 'cocking' the workpiece.