Need help with angle tenon jig cut

[Brian Steinberger]

I tried and tried to avoid asking for help but I am just at wits end with this. I am trying to make a flag display case. I’m cutting the angles in a tenon jig on the table saw. The saw is new to me in the last month so I’ve been spending time setting it up. Ive tuned it up and checked it multiple times now and it is dialed in. These are the results so far. The cut is skewed somehow. You can see in the pictures below how the final cut no square across the board. I marked a pencil line in the one photo that is square so you can see. And you can see in the third picture how uneven the cut is off the table.

What am am I doing wrong? The jig is PERFECTLY 90 degrees to the table in both directions. When I set up the saw I even adjusted blade to miter slot at 45 degrees and had to add a thin shim above the back two table bolts. I have tried this cut with different blades and get the same results. I’m so confused at this point. Any help is appreciated. Thanks.

[mreza Salav]

Your blade is not parallel to the fence (at least not in 45 degree) or your jig is not held tight against the fence all along.
Adjust the tail end of the fence and check how it changes.

[Andrew Hughes]

Will the saw rip 45s on straight stock.
To me that would be my first guess.
Other then that is has still be your set up or accurate milling of the piece your cutting. Impossible for anyone to know without standing there.

GoodLuck

[Brian Steinberger]

Thanks guys. Yes the fence is parallel to the blade and miter slot. I’ve gone over everything multiple times. The stock is milled up flat and square. Maybe I’ll try moving the fence tail inward and outward tomorrow to see if that moves me in the right direction.

I don’t have a good way to check the blade parallel to the miter slot at 45. So I just use a combination square and feeler gauges. Seems right on to me. I would like to use my dial indicator but don’t have a jig knocked up yet to get the indicator at 45 as well.

[johnny means]

Am I missing something. What's the point of cutting a 45° angle with the board held vertically?

[Doug Garson]

Not sure how you adjusted your saw to get the blade parallel at 45 degrees here's an article on how to do it in post 109 of this thread

https://forum.canadianwoodworking.com/forum/tools/power-tools/1252567-used-unisaw/page3

[Doug Garson]

https://forum.canadianwoodworking.com/filedata/fetch?id=1254253&d=1570299200
https://forum.canadianwoodworking.com/filedata/fetch?id=1254254&d=1570299242

https://forum.canadianwoodworking.com/filedata/fetch?id=1254255&d=1570299296

[David Buchhauser]

Am I missing something. What's the point of cutting a 45° angle with the board held vertically?


I had the same question. I don't get the 45 degrees.
David

[Steve Jenkins]

Try using two clamps to hold the piece to the jig. Using just one can allow the workpiece to pivot slightly when the blade contacts it.

[Brian Steinberger]

I’m actually cutting vertically at 67.5 degrees to make the corners for a flag display case. I’m checking my saw blade parallel to the miter slot at 45 degrees to accurately make this cut.

[Brian Steinberger]

Doug thanks for that article. That appears to be what my problem is.

[Brian Steinberger]

Try using two clamps to hold the piece to the jig. Using just one can allow the workpiece to pivot slightly when the blade contacts it.

I tried two as well and still get the same result. I had thought this could be the problem as well.

[Alan Schwabacher]

When you say the jig is perfectly square to the table on "both" directions, that could be a problem. It needs to be square in three directions to cut accurately: the surface the part is clamped to must be square to the table, the fence backing up the piece must be square to the table, and the clamping surface must be precisely parallel to the miter slot. If that surface were twisted out of parallel a tiny bit, you would get the observed cut.

[Brian Steinberger]

When you say the jig is perfectly square to the table on "both" directions, that could be a problem. It needs to be square in three directions to cut accurately: the surface the part is clamped to must be square to the table, the fence backing up the piece must be square to the table, and the clamping surface must be precisely parallel to the miter slot. If that surface were twisted out of parallel a tiny bit, you would get the observed cut.

Good point Alan. The jig is absolutely square to the clamping surface and back fence to the table. The clamping surface being parallel to the miter slot would be the fence since this is riding on the fence. I have my fence set parallel to the miter slot. Wonder if maybe it’s not holding that accuracy or flexing somehow? I have a grizzly 1023RL with the shop fox fence.

[Lisa Starr]

Do yourself a favor and consider replacing the fence in the near future. I fought with that fence on my Grizzly for years...I finally replaced it with a new front rail assembly that I made myself and a Very Super Cool Tools fence. I can't figure out why I fought the other for so-o-o-o-o long.

[Brian Steinberger]

Do yourself a favor and consider replacing the fence in the near future. I fought with that fence on my Grizzly for years...I finally replaced it with a new front rail assembly that I made myself and a Very Super Cool Tools fence. I can't figure out why I fought the other for so-o-o-o-o long.

Lisa, what exactly were your problems? I notice the faces aren’t flat so I shimmed with
painters tape under neath no make it flat within .003. I also had to shim slightly to get the faces square to the table.

[Bruce Wrenn]

Instead of tilting blade for angles, why not leave blade at 90, and BUILD a couple of angled sleds to hold work pieces. Once your friends find out that you built a flag case, you will be asked to do more, which will be easy as you already have jigs to make cuts.

[Brian Steinberger]

Instead of tilting blade for angles, why not leave blade at 90, and BUILD a couple of angled sleds to hold work pieces. Once your friends find out that you built a flag case, you will be asked to do more, which will be easy as you already have jigs to make cuts.

This is a great idea Bruce and something I’ve seen done before. I would likely build one for 67.5 and 45. I will probably do this when I have more time. I need to get this flag case done very soon.

[Brian Steinberger]

I have fixed the problem today. This afternoon I “re-tuned” the saw again with nothing more than a combi square and a lucky tooth on the blade. I was very meticulous and got it just right. Not much work needed to be done from where it was. Next I carefully aligned the fence to the miter slot. Before trying this cut again with the jig I left the saw at 45 and made some cuts with the miter gauge and the piece flat on the table and the cuts were perfect, so I knew the setup was right on. Then I set up to make the 67.5 cut. The only thing different I did was to clamp the piece to the jig with two clamps as Steve suggested. I clamped rather tight as I thought this really could be the problem. The cut was right on.

So the good news is that I fixed the problem, the bad news is that I’m not sure exactly what the problem was. Could have been a combination of a few things. So thanks everyone for your suggestions! Hopefully this can help others in the future that are having the same problem.

[David Buchhauser]

Hi Brian,
Please post some pictures of your finished flag case. I would love to see it!
Thanks,
David

[Brian Steinberger]

Hi Brian,
Please post some pictures of your finished flag case. I would love to see it!
Thanks,
David

Will do David!