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Table saw help

2K views 13 replies 8 participants last post by  Rebelwork 
#1 ·
I picked up some rough hickory and wanted to joint some pieces. I made a joiner jig out of some 3/4" plywood and straighten one edge on two 36" pieces. When I put those two pieces together the ends seems to match up pretty tight but the middle has a bit of a gap. Even when I put a pipe clamp on them I still have a noticeable gap. I've checked the blade and it's square to the table. Not sure where to look next? Thinking I'll change the blade BUT if it was the blade then why would the edges fit tighter. I would think the entire board would have a gap. Any thoughts are appreciated..
 
#2 · (Edited)
Here's what I know ....

If your workpiece/jig has a curve that's registered against the fence, your cut will have pretty much that same curve. Anything placed against the fence must be dead straight, either by jointing or a factory edge. Check you jig's face that's against the fence.......... :|
 
#9 ·
See posts 3 and 5 .....

Post 3: That's the first thing I asked him
Post 5: Then he said he used a factory edge.


If your workpiece/jig has a curve that's registered against the fence, your cut will have pretty much that same curve. Anything placed against the fence must be dead straight, either by jointing or a factory edge. Check you jig's face that's against the fence.......... :|
Steve, this may be something you've already done, but did you check the straightness of your jointer jig where it goes against the fence?
That's some pretty wood!

So, either the factory edge is not straight or the fence face is curved, but he said he replaced that as well....mysterious.:surprise2:
 
#5 ·
I purchased a new 4x8 sheet of sanded plywood and used the factory edge. I measured the width of the jig and it's consistent. This is an old table saw so I tried adding a piece of wood to the fence just to make sure I have a flat rip fence. Didn't think this was an issue but trying whatever I can. I measured from the rip-fence to the slots in the table..front, middle and rear. All the same. This shouldn't be the problem but when squaring the blade with carbide tips do you square the table to the blade face or the carbide tip? I did the blade face.. Also If that was the issue then the entire cut would be off. Here are a couple pictures. Appreciate the help.

Also, I am working with 10" wide hickory planks. I saw a video where the guy said it's best to split wide boards and reglue to keep them from cupping. That's what I did on this first board. Is it possible there is something with the wood? I've seen pine boards twist up pretty bad when splitting. Nothing like this just in the middle but just thinking out loud. The wood is also 1" thick. I just got a thickness planer for Christmas :smile2: Haven't used it yet. Was going to split and glue up all the pieces before planing them all down to 3/4 before joining to make panels. Wanted to try to figure this out before working on the next piece. Think it might be best to plane the boards first? Grabbing at straws to figure the best way to proceed. Thanks again.
 

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#6 ·
Fixing it at this point ....

I'd use a hand plane to remove a slight amount off each end. Keep the edge at 90 degrees by laying the board face down on the bench, elevated about 1/4" and run your hand plane sideways or turned 90 degrees .... like a shooting board. Obviously, clamp the workpiece to the bench to prevent it from moving while you apply hand plane pressure. OR you can try your skills by orienting the edge up and using the plane in the normal position.


The real issue for me is why you get a curved edge from your "board straightening" jig? I made mine from a piece of hardboard, factory edge against the fence and used Maple for stiffeners. The toggle clamps were from Harbor Freight. It's 8 ft long:
https://www.woodworkingtalk.com/f27/board-straightening-jig-table-saw-16999/


 
#11 ·
It looks to me from the wood grain that there was stress relieved in the board when you ripped it. Was the wood acclimated for a while in your shop before you ripped it? Woodnthings jig should help you bring it to straight again.

The width of your plywood may measure the same at different points along the length...But it may have followed a slight radius in the factory edge. Before ripping long joints (whether using a jig or not) the wood should be acclimated to the environment because the center of the board's width is always a bit moister than the edges, and when sawed will cause it to try to reform to it's natural tree like shape.

Another tip, before gluing consider arranging the boards so the grain rises as much as possible in the same direction, which will reduce chip out when surface planning. And plane so the plane blade will skim over the rising grain instead of catch the rising grain (causing chip out).
 
#12 · (Edited)
Thank you for the help. I did use new plywood and the factory edge. The jig is straight from end to end using a t-square. I know it's backwards in the picture for those that were going to point out. :smile2: The rip fence is straight measured with the miter groves in the table. What I was leaning towards is what Gary mentioned. Here is a pic of where I have the wood stored. My shop is in my basement. Had the wood here for a couple months now. The piece I took was from the top. I did notice the wood bow when I split it. It bowed quite a bit. I thought the jig would take that out or I could bring them back together with the clamps. Is it possible the wood is retaining or creating a slight bow right after I cut it? I'll be adding spacers between the boards later today. 3/4 x 1 1/2" wide pieces of plywood good or is the 1 1/2" too much? About how long before it's acclimated enough to work on? I know that's a tough question based on how green it might be.. but how do you know?

Should I run these boards through the thickness plainer before doing any work straightening or sizing? If you had these 10" wide boards would you split and reglue them? Being the cart I'm making is 20" deep and I haven't dressed these boards yet I will have to add a piece to them to makeup the 20".

Thanks for all the help. This is my first time working with this type of lumber so I feel like such a newbie..
 

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#13 ·
Wanted to post an update. I'm pretty confident the problem I've experienced is due to the wood not being properly acclimated. I took a piece of 3/4 plywood and cut 2 strips using the jig that I made. I then mated up the opposite pieces and they joined up fine. If there was a problem with the jig, blade or fence I feel I would have seen it on these pieces as well. I cut up the 3/4 plywood in to 3/4 x 3/4 x 12" pieces and restacked the wood with these spacers. Not sure how long to wait before trying to work with them. Figured I'd give it a couple weeks and go at her again. Appreciated the responses and help!
 
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