working out offset when cross cutting on tablesaw

[mickthetree]

Evening all

I made a crosscut sled for my table saw and it works a treat. I was cutting come lap joints on it last night. I put a stop on the fence for the end of the cut, then used a piece of spare stock the same thickness to offset the piece from the stop thinking it will give me two cuts the perfect thickness of the stock.

CLANG!! Didn't take into account the thickness of the blade. Is there an easy way to do this so I get a nice tight joint? I guess what I need is a piece of stock the exact thickness minus the thickness of the saw blade, but is there an easier way to do this? I think I've seen some gadgets that are supposed to do this, but I'm sure there must be a simple solution I just havent figured out yet.

Many thanks.

 

[xy mosian]

Not a perfect solution, but shim the first cut by the thickness of the saw kerf.

xy

 

[mailee]

Well there is a way to do it, make our own jig like I did.

These are available from the USA but are a bit expensive so I made my own Kerf jig and it works great. All you do is make a test cut to work out the kerf of your blade and set the jig. once this is done you can repeat very accurate cuts over and over. HTH. :wink:

 

[jasonB]

Simple way is to cut a bit of scrap and keep it held against the fence, pull back the sled and put your gauge piece against the freshly cut end of the scrap, this will give you the correct offset to place your stop against. Also less chance of errors than those little gadgets.

J

 

[mickthetree]

ah! right, that makes sense. I'll try that out tonight.

Alan, that looks great. Looks like what I found online last night. When I saw it I thought I could make one of those! Glad to see someone else has managed it.

 

[wcndave]

The kerf should have no affect here should it?

let's say you have a piece PAR and overlength (as would normally be from the result of planing.
say it's 24" and you want 20" piece with lap.

you trim one end clean on sled
turn it over and cut other end to 20" with a stop in place.
now the edge of the wood, the "zero" point is at the edge of the blade.
put a piece between stop and stock like you did, and it will move it the width across.

kerf does not come in to play in this scenario, or am i missing something?

 

[mickthetree]

What I'm trying to achieve is a lap joint like this...

Opened up it would look like this...

This is my crosscut sled setup...

So I'm using the spare stock as a spacer from the stop block, making a cut, then removing the spare stock and make another cut, then clean out between the two cuts.

I'm left with a halving joint that is the width of the spare stock+the kerf of the blade.

I've been sketching out some designs for something very simple that I could attach to the stop block so I could reuse it as long as I use the same blade.

 

[wcndave]

ah....

one other way then... is to cut your spare stock down the middle, then glue it back together again.

 

[mickthetree]

ah!

That'll do it!

erm.... was it really that simple?

 

[mickthetree]

now I feel stupid. wheres the delete thread button?

Actually I can see some scope in having an offset feature in the stop block so no matter what stock is being used I could switch it on or off.

 

[wcndave]

yes, it could be neater. however if you use different blades for different things, it could change. I find this way easy, quick, and surefire.

sometimes these really obvious solutions are just not at all obvious, until you see them, then it's facepalm time....

 

[wcndave]

in fact, you don't even need to glue it, although then i find i lose one piece within 0.00002 seconds

 

[mickthetree]

Yup, that sounds like me. I'll get the glue out!

 

[ossieosborne]

Here's a few kerfmakers:

Simple one from Shopsmith

A selection from Lumberjocks

Some of them are works of art. Interesting projects though.

Oz