Ridgid table saw not cutting 90 to make a table top
So here is the skinny.
Ridgid R4516
Brand new Dewalt blades
Checked alignments on the blade being 90 to the table top, parallel to the miter slots, parallel to the fence.
Different wood from scrapsof maple, Poplar and plywood all producing the same
Measurements are to the .004.
Peice is run through a planer and jointer prior to the table saw
Isssues is
When the cut is made the bottom of the peice has cut marks, like if it was being pushed towards the back of the blade.
When I make 2 cuts and keep the tops together, perfect, no seem. Flip both peices over and boom gap. Flip 1 of them over and minimal gap.
It’s almost as if the blade is / towards the fence. Checked and it’s at a. 004 difference from bottom to top of blade. when checked with a machinists square there is no light.
It’s not at an angle. At least not the whole height of this peice. It looks like from the half way point there is a second angle and it looks like the back of the blade is doing it
Any ideas. Below is a pics of the marks it’s leaving behind where the back of the blade is causing the problem. A front face view and a birds eye of both sides.
Replies
Have you checked whether the fence is square to the table? If it’s not and it’s angled away from the blade even slightly, it could be that the pressure of pushing the piece through is enough to lift the cut side up which would produce the result you are seeing.
Wow.
A difficult and well-described problem.
It is very unlikely, but it is worth checking that the blade is totally flat - even a new blade can be damaged.
Also you don't specify that you have confirmed that the blade is parallel to the fence. It is possible that it was not installed true, or that there is some in-drift of the fence at the back. Your exactitude suggests you will have already checked!
Finally, is the table flat? Should be of course, but worth a check.
I have the 4512 and about the only thing I can think of relative to your issue is fence alignment to the blade, which has already been mentioned.
What is the age of your saw? Ridgid did have a recall on the 4512's arbor being a little wacky, but the II version fixed that.
I assume you are using a carbide tooth blade. If so, when you use your machinists square, are you placing it only against the saw plate and not touching any of the teeth?
Are you using a feather board to hold the work piece snug against the fence?
Is your throat plate flat and flush with the table?
If the saw marks you mention are being made as the rear teeth are coming up out of the table, the work piece may being lifted slightly as it passes the rear teeth. You may need to adjust your fence so that you have a very slightly greater distance between blade teeth and fence at the rear. This together with a feather board may help. Also, use a shoe type push stick (https://ibuildit.ca/projects/plywood-push-stick/) that will help hold the work piece down against the table.
Aside from that, you mentioned making a table top. When preping edges for table top glue-up, it is best to use your jointer and, when doing so, alternate the piece orientation as you pass them through; first piece with the top against the fence, second piece with top away from the fence, etc, etc. This compensates for any slight out-of-square your machine may have. If you use your table saw for a similar function, it is good practice to follow the same process; top down, top up, top down, etc.
Always difficult to respond to these without hitting a nerve. If I do please be assured it is not my intention. I will assume a thin kerf blade although I did run full kerf rip blades on my lower powered saws with good success.
DeWalt's 7670 dado stack is a diamond in the rough and provides results that are surprisingly good. I certainly may have missed another unexpected jewel but, it seems the balance of DeWalt's blade offerings are focused on the building industry. There is nothing wrong with that but, it seems you are looking for a lot more accuracy than one finds in tract homes.
For more precision work with a thin kerf blade I would start with something like an Industrial Series Freud. Although they are a common enough maker, I had better luck with the upper-end Freud blades than some of the upper tier names early on. All of this blah, blah assumes that a job-site blade may waffle or react to heat more than a better product; I could be going down the wrong road.
If we assume the blade is not a contributing factor, we need to look at the saw and the saw's setup. A lot of folks have had great success with the Ridgid 45xx but, as with any brand, there have been QC issues here and there. To keep it simple, let's assume the blade and the saw are both fine.
I am making this leap because in your original post you give me the feeling that you are a diligent person who would check and re-check things. During such a process you would find things that worked one way one time and another way at another time indicating something that was not stable and consistent; cracked casting, excessive backlash, etc.
This leaves alignment and technique. We all know we can achieve a good result if the machine is capable, the cutter is good quality and our technique is sound. The pic below is 8/4 beech cut on a 113. Craftsman contractor saw probably with a Freud or a Amana blade as that was what I was using at the time. Not what you would call a top-of-the-line setup but, a good result.
Much is made of aligning the blade with the miter slot and this is a good place to start. I catch a lot of folks aligning to the right hand slot when the left hand slot is where they run their miter gauge. I just mention this in case. You are concerned with 90* cuts so we won’t worry about bevel alignment although you may want to go there eventually.
Once the same tooth on the blade checks good at the front and the rear of rotation in relation to the miter slot you can check that same miter slot’s alignment to the fence. I also go back and check the blade to the fence just to make myself feel better. So much for alignment.
If all that checks out we need to look at technique. For rip cuts you can employ feather boards to assist in material control. Your feed rate should reflect the saws power and should be consistent; think of yourself as a manual power feeder ;-)
Your control of the material should be consistent before, during and after the cut. We’ve all seen folks who shoot the material through the whole operation or give it a quick shove at the last inch. That’s fine if your getting paid by the part but, it doesn’t save any time if you want clean, consistent results.
I've rattled on so long few will make it to the end of this already but, review your alignment, consider your technique and let us know how it goes.
P.s. Check the result of your jointing and planing. Be sure that faces, edges and ends are square to each other. That is; just because a board went through the jointer doesn’t make it right, eh?
Thanks for the guidance folks.
-3 diff blades, same result
- Push stick is shoe style
-Checked between teeth
-Bought in 2015
-Will be looking at the table
-I will be checking the jointer and planer again when i get home tonight.
If the board, regardless of height, having the same issue then its the fence, the blade, splitter, or arbor when on? As if the jolt of turning it on forces it askew, unless it's me. (OP error).
What i will try is:
Making a temp fence and passing it then
Raising the blade well above the board and checking for the marks
Checking the jointer, planer
Remove the blade and turn on the saw to check the arbor for movement
If it is the fence. Would it mean its more \ or / when facing the table?
The throat plate has play in it, it bends if i use my fingers to push it down. It sits below my table height and the board is wider that it rides on the table not the plate. I also have pressure near the fence pushing the down with the shoe. (not at the fence).
Ill keep you posted on what i find.
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