I cut allot of prefinished material, Nova ply etc. The problem I have is when I do a mitre wrap the middle of the joint is open. In other words the cut is not straight. There always seems to be a 1/16 to 1/32" deflection. I've changed how I hold the saw, I always clamp the fence. I've used a clamp in the middle of the fence. But still the mitres are open. What am I doing wrong? I have the hand skills and I'm a pro, but this ones is kicking me.
Bowed Long Mitres
- Thread starter joinery45
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Frank-Jan said:
Aaaah, got it. Certainly wouldn't take much for a long joint like that to be open. Maybe the TS55 jointing technique would work depending on how critical the panel size is or just allow for an extra cut in the length.
Seth
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This seems to have come up more recently. If I recall correctly, most members found that making sure the workpiece was adequately supported and straightly supported (on a flat non bending surface) helped the situation out like Frank-Jan suggested.
Peter
Peter
mouppe
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For me a little opening in the middle is ideal. If not, I would take a plane and take a couple of shavings from the middle to create a spring joint. As long as your ends close, the extra pressure required to close the middle will strengthen the joint. Also, shrinkage occurs more at the ends so this will help keep your mitres closed.
Thanks to everyone for the comments. I use two MFT 1080 joined together and dead flat with plastic shims. My first introduction to Festool was from Solid Surface Guys and there biggest complaint was the tracks bowed when using a router. That was understandable because more often than naught your applying a lateral force. The SS G's would back up the Festool track with a square straight edge. Later at AWS in Anaheim I mentioned this to Festool and they denied, out of hand, the tracks would bend. Surprisingly three years later they (Festool) came out with the 2 Series tracks.
Back to my problem. I have two FS3000/2 Tracks and if I put the aluminum edges together (rubber outside) there is a gap of 1/16" between the two. No big deal 1/32" each.
Whey I process sheet goods I first take 1/2" off the long edge. But if I reverse the track and use the aluminum edge as a straight edge I'm bowed out in the middle by 3/32" or so, its always convex so to speak. If I them come back and mitre that edge. I'm now bowed in. Since using a Plunge Saw for straight cut the control force is straight down and clamped at both ends the bow would at max be 1/32" either way. It's not.
When I mitre sheet goods (MDF, Armour Core, or A1 veneer core) the problem is the same. Mitre cuts involve lateral forces but no way near that to account for the bowing.
Back to my problem. I have two FS3000/2 Tracks and if I put the aluminum edges together (rubber outside) there is a gap of 1/16" between the two. No big deal 1/32" each.
Whey I process sheet goods I first take 1/2" off the long edge. But if I reverse the track and use the aluminum edge as a straight edge I'm bowed out in the middle by 3/32" or so, its always convex so to speak. If I them come back and mitre that edge. I'm now bowed in. Since using a Plunge Saw for straight cut the control force is straight down and clamped at both ends the bow would at max be 1/32" either way. It's not.
When I mitre sheet goods (MDF, Armour Core, or A1 veneer core) the problem is the same. Mitre cuts involve lateral forces but no way near that to account for the bowing.