Table Saw Jig

[Pablo]

As a complete beginner, I was stoked to successfully make anything!!

I got the ideas from a Time/Life video mr dear old Mum got me. I have to put the perspex guard above the cut line.

The difference in making cuts more precise is stunning.

The runners are made of pine and I'll replace them with some plastic at a later date. Did I read about some silicon or nylon that somebody else on this BB uses?

Any suggestions gratefully received.

Cheers

Paul.

[Wayne Davy]

Nice Job Paul.

The best plastic for runners is "UHMW polyethylene" ie the same stuff most plastic breadboards are made of. Can be expensive to buy from the plastic retailers and the best source is, you guessed it, breadboards from the bargain stores. Whats so good about this plastic is that it is:
a) Self lubricating - ie. slides nicely all the time in mitre slots
b) Very, very long wearing
c) Easy to work with
For some ideas, try this: http://www.leevalley.com/wood/page.asp?page=32045&category=1,43455,43831&ccurrency=3&SID=

One last thing - I think you have raised the blade for the pic but, if not, always lower the blades so that the teeth are just above the thickness of the wood you are cutting. Safer and a better result.

Cheers,

[Rocker]

I notice that there is a kerf in the block of wood on the near side of the sled, which is supposed to protect the user from the saw blade emerging at the end of the cut. This indicates that the sled does not have a stop to prevent it from travelling too far forward and thus allowing the saw blade to emerge.

This is easily cured. You just bolt a small block of wood to the side of the saw table and another small block in a suitable position on the bottom of the sled, so that the sled is stopped as soon as the full height of the blade has entered the rear fence, but before it emerges at the back. I have put hooks in the block attached to my saw table which I hang the mitre gauge and push sticks on.

[Pablo]

Thanks for the suggestions - I'll continue tinkering!!

Paul

[Helix]

Originally posted by Wayne Davy
One last thing - I think you have raised the blade for the pic but, if not, always lower the blades so that the teeth are just above the thickness of the wood you are cutting. Safer and a better result.

I have read an alternate view on this recently. The thought was that with the teeth just above the surface, the blade tends to force the work back at you (kickback) as the teeth are travelling in that direction at the point of cut, whereas with the blade raised, the work is forced down on the table instead.

I must agree that the blade can't cut you if it is bellow the surface, or close to it, but i can see the point of view.....

Cheers,

Josh

[Justin]

When I got my table saw I did a lot of reading re. blade height, and came to the conclusion that you get a smoother cut if the teeth just clear the material, but less chance for kickback if the blade is at maximum height.

- The smooth cut is a result of more teeth being in the material and a lower shear angle on the wood fibers. Flip side of this is a slightly higher possibility of kickback, owing to the teeth being more tangential to the material.

- The less smooth and safer cut is with the blade at full height, as the cutting action of the teeth is more vertical than tangential. A higher shear angle on the material means more torn fibers, but this angle also forces the material down against the table , rather than back towards the operator.

Of course there are a bunch of other variables that may affect the above examples, so I'm not putting them up as the definitave guide to blade height (nor am I putting myself up as the definitave expert, either).

With the blade at any height of course some kind of guard needs to be in place. Keeping things in context of the original crosscut sled posting, perhaps a low blade height is safest considering that a guard can't be used with the crosscut sled.

Perhaps we've got the makings of a lively (but hopefully civilised) debate. I'd be interested to read any other opinions.


Cheers,


Justin.

[Pablo]

The blade was raised for the photo - but I too read the article on blade height and am now more confused than ever!

I guess confidence working with the machine defines your desire to risk the higher kickback setting.

There will be a guard (of sorts). In the video I made this from, there is a piece of perspex mounted on blocks that runs from one side of the sled to the other above the cutting line.

I hope that's a clear mental picture for you. I am waiting to get the perspex.

I like the "stop" idea - rather than the 1/8'' cleavage that the blade is trying to give me - thanks.

Cheers

Paul.

[derekcohen]

Justin wrote:


When I got my table saw I did a lot of reading re. blade height, and came to the conclusion that you get a smoother cut if the teeth just clear the material, but less chance for kickback if the blade is at maximum height.

Justin, in my experience I find that I get a cleaner cut with the blade up high than with it set low. My reasoning here is that the teeth are cutting with more vertical force and across the grain. A low blade tends to cut at an angle and is more susceptible to chipping out. Just my observation.

I agree about the danger of kickback with a low blade. Frankly the only reason for a low blade is safety.

Regards from Perth

Derek

[Sturdee]

Paul,


Nice job and I am sure it will help your woodworking.
To make the sled more usefull I would include a T-track so you can attach some removable toggle clamps and stops to secure smaller work pieces to the sled and keep your fingers out of harms way.
I would also attach a ruler going both ways from the saw cut line to assist in measuring and with bolts and wing nuts you can attach mitre blocks to cut mitres.


Regards,



Peter.

[minis4meau]

I'm off to buy a bread board..... Great thinking.
Barbara