Table saw fence question

[Ateallthepies]

I understand the principles of table saw fences and the use of a short fence for reaction wood cutting but when trying to rip long lengths of board or even timber, the cut at the end can be less than straight due to lack of support that a long fence will give.

Now here is my question, is there a product that can fit onto a short fence that replaces the fence past the cut and gives support but also allows some sideways movement if the wood wants to wander. Maybe some sort of roller system that under no stress stays in line with the fence thus giving support past the cut but if any sideways movement occurs will move on some sort of spring loaded thing and stop the wood from getting stuck on the blade?

Is this sort of thing viable?


Steve.

 

[jimi43]

The short fence should be of such a length that by the time the wood passes the end of it, it is already cut.

If you guide the wood against the fence it should present no problems. If you don't...it will skew and probably kick back anyway!

Anything behind that point is unnecessary and down right dangerous.

The only issue with short fences is if they are cheap and poorly supported to the feed end then they can themselves flex out of true...a long fence clamped at both ends prevents this.

The answer to that is use a long fence supported at both ends and a short stub sub-fence against the main fence.

There is an interesting thread HERE

Jim

 

[Carlow52]

A properly set riving knife of the correct width will do a lot to reduce the risk of kickback.

 

[Steve Maskery]

You are right to recognise the trade off between better support for the last few inches that a long fence gives and the decreased risk of kickback that a short fence gives.

There is a skill to using a tablesaw and part of that skill is in feeding the timber. As Carlow rightly points out, a properly sized and adjusted riving knife will help enormously. The rest is up to the user. Just learn to push straight!

Cheers
Steve

 

[Ateallthepies]

That's strange, I posted a reply after jimi43 and it disappeared??

Thanks for the replies,

Yes I made a short over fence like in Steve Maskery's video for my TS-200 and added a couple of Mag-switches which lock the far end down to the table bed.

I guess I just need more practice to get that last little bit cut straight?

I just thought some sort of gizmo placed on the long fence in the gap past where the short fence ends that is able to retract under pressure if the wood want's to move but stays in line with the shorty with no pressure would be nice for support.


Steve.

 

[jimi43]

Try the link I edit posted in my first post...it has such gizmos and gadgets in it....

Steve's DVD is pretty darn good too!

The riving knife is the key to most kickback situations...the thickness of the knife must be midway between the kerf and body thickness of the blade to be effective. Do not make the mistake of retrofitting with a thin kerf blade without changing the riving knife to suit.....the stock will just bash into the existing knife....and more importantly....most problems occur when retrofitting with a new OEM blade which is not suitable...like has a thicker blade body and kerf.

This renders the riving knife useless...the wood may pinch...the knife does not prevent this, being too thin and kickback can occur.

Cheers

Jim

 

[Ateallthepies]

I checked out that link Jim, thanks.

Yes I bought a magnetic feather-board and this greatly helps when I am able to use it as I only have to concentrate on pushing the wood in a straight line and the feather keeps the wood tight to the short fence right to the end of the cut-almost!!

It is the wider pieces that were giving me trouble as I could not use a feather board and had to concentrate on pushing and keeping the piece tight to the fence.

This is the sort of gizmo I had in mind...

Steve.

 

[Hudson Carpentry]

Sounds like you could do with a saw that has a sliding arm or even a jig that does the same thing but slides in your mitre slot.

 

[Steve Maskery]

No, Steve. No. You are asking for trouble, my friend.
I can understand your thinking and actually, I've similar thoughts myself about "distant support" See, I've even given it a name

But the solution you have there is crying out to catch the end of the board, get stuck, then as you try to jiggle it to sort it out the world turns red as your attention is distracted.

I was going to keep this under my hat until I'd worked out the details but as you've raised the particular issue...

I'm thinking of having a two-part fence, the front half stopping short of the TDC as currently, and a subsidiary half, with a wedged front end, so that it "catches" the workpiece, situated behind the blade. I've not tried this yet, so do so at your own risk, but my feeling is that it will give the workpiece some support on the far side, without preventing the last end from clearing the blade.

Does that make sense? I'll draw a pic when I can see properly again.
S
Edit: I've just realised that I've used the word "catch" and in one case it's a negative and in the other a positive context!. I don't want the workpiece to catch and be impeded, but I do want it to be collected on its unimpeded way through the machine. I hope that's clearer!

 

[Hudson Carpentry]

The spring idea and Steve's point about the work piece may catch the end of the string plate. A solution to this would be to curve the front end of the plate, so if a work piece wasn't perfectly hitting the plate it would move the plate slightly rather then the board jamming against it.

 

[Ateallthepies]

Is this the sort of idea you have Steve?...

The leading edge would need more of a slant than the one in my drawing and would need to be further away from the blade?


Steve.

 

[Steve Maskery]

Is this the sort of idea you have Steve?...

The leading edge would need more of a slant than the one in my drawing and would need to be further away from the blade?


Steve.

Yes, but as you say, a longer slope and further back. But that's the general idea.
S

 

[moz]

You know, that drawing is really no different to a full length fence. The whole point of a short fence is to allow space for the cut timber to move. Whether it's a point fence , as shown, or a full length fence, the effect is basically the same or even worse. Occasionally, a board can move to an alarming degree, more than that lead-in slope has allowed for, and I can just see someone getting into a right pickle with this. It's a dangerous solution to a non-existent problem. Think of it like this. If the timber has moved after cutting, then using the cut portion as a reference is hardly likely to improve straightness, is it? It's not just a safety issue, though that is of course most important. It's also more accurate to reference from the uncut portion of a board.

John

 

[goldeneyedmonkey]

As long as you have sufficient support (whether it be a long out-feed table, or roller stands) then it shouldn't really be an issue methinks? As long as the board is in contact with the fence where the blade meets it it should be fine. Or am I missing something in the original question here?

_Dan.

 

[OPJ]

Generally speaking, I find it's much easier to keep the cut running perfectly true to the end on a larger saw with a larger diameter blade. Your saw has a 200mm blade, which probably doesn't make things any easier... I also now own a saw with an 8in blade (Elektra Beckum PK200) and find the same problem with the wood drifting away at the end of the cut. Though, I never had this trouble with larger saws I've used previously at work and college.

As Dan has just mentioned; I think that having decent outfeed support could make a lot of difference, here. If you don't have the space for a permanent outfeed table/support to be levelled perfectly to the top of the saw then, in one of Steve's earliest DVDs, he shows you how to build an excellent and highly durable outfeed table that hinges up and down behind a table saw. I'm not a fan of lightweight roller stands, particular where the workshop floor is uneven, which could lead to the roller being out of parallel with the table saw's top surface.

 

[Guggs]

The fence on ANY rip saw Should not extend pass the blade .The fence should just be set just inline with the arc of the saw blade . What can happen is the timber can bind on the fence and cause kick back . There are several 'things' that should be observed ,
A- is the riving knife the correct thickness for the blade ?
B- what type of rake has the blade got ?
C- is the blade sharp ?
D-try using a push spike .
E-is the blade parallel to the table mounting ?
F -do you have a 4ft take-off table that can support work load ?
Using fancy fences have their places but general rip-cuts ,then no !
Try looking closer 'to home' !