Raised panel door problems

[Philip Johnson]

I was out playing in the shop trying to make some raised panel doors and ran into a small problem. When I cut the ends of the rails to fit into the stiles, I had to adjust every corner to get them to fit good. All the wood was the same thickness, but for some reason I had to raise or lower the cutter to make every corner come out flush. Any ideas on how to avoid this in the future.

Thanks
Phil

[Jason Hallowell]

I had the same problem a while back. In my case it turned out that the stile profile wasn't perfectly even along the length. This was due in part to my router table top not being perfectly flat, and me not using enough feather boards when cutting the profile. A new router table top, and lots of featherboards, and no more problems.

[glenn bradley]

I agree with Jason. This sounds like a material control issue. I use a coping sled (http://www.sawmillcreek.org/attachment.php?attachmentid=43930&d=1154660657)if I am going to make many such cuts.

[Joe Scharle]

Yes, you'll find that a coping sled provides a more consistent feed to the bit.

[Philip Johnson]

Thanks for the hints...I believe my wood was good, it was all jointed flat and came out of the planer at the same time. The stiles were cut on a shaper with a power feed so I think they should be flat and true but I will take a look at them. I will have take a look at a coping sled, the problem must be with the rail end then. I will have to figure out someway to clamp the rails in place.

[Peter Quinn]

A few thoughts, for what its worth, from a guy that has made every mistake at least twice.

So are you using a shaper to cope the rails? And if so, how are you passing them through the cutter head and what type of fence setup are you using? And how far below the stock have you set your feed wheels for the molding cuts on the stiles and rails? If you are using a manual hold down scheme (ie your hands are holding the rails to the table) that is the most likely source of error.

On any shaper setup you want to RAISE the cutter head to its final height to eliminate any slop or back lash in the spindle height mechanism. Its a more pronounced problem on older machines with more hours on them, but if you attain your matched height by lowering the head on any shaper it can drop a few thousands under load which will lead to some strange non-flush issues. Always come UP to a height setting and lock it in securely.

For the coping cuts, check that your fence is 90 degrees to the table, make sure your fence or plates (if using a split fence and rub collar) are flat, check that your fence is parallel to the travel of your miter gauge, coping sled or sliding carriage, keep your table clean so that chips don't get between the stock and the table, check that your spindle height is locked and the lock is working.

Next possible issue, does your door set run both cuts in the same orientation? Assuming standard CCW spindle rotation, some sets work cope face down and mold face down, some work cope face up and mold face down (and it is beyond me why). I prefer the former as any minor alignment issues caused by differences in stock thickness are canceled on the front of the door and pushed to the back. Having passed all your parts through the same planer setup is good practice but unfortunately not a guarantee that they are precisely the same thickness, so check that. With a few thousands deviation from side to side on the planer, which is possible due to knife alignment, head alignment, crumbs on the table or age of planer, you can have problems with a cope face up mold face down set up as the deviation is added to one cut and subtracted from the other, effectively doubling the error. I check stock thickness closely with calipers to verify accuracy.

These are a few of the things I have done wrong to achieve results similar to yours. Also, check your stock closely with a machinst's square and your jointer table to verify it is square in all planes and flat over its length. Wood does move when your not looking, sometimes even after jointing it into submission! Pesky product this wood is..:D

[J.R. Rutter]

I'll just add that you may want to check the sticking groove location. In addition to the possibility of backlash in the height adjustment, anything trapped under a stile as it is fed will cause the sticking cut to move down on the edge of the part. Sawdust, chips, etc... Ditto on the cope.

[Philip Johnson]

Peter you bring up so good things to check..the shaper is a new powermatic so I don't think the equipment is the problem. I did not set the height by raising so I will make sure to do that in the future. It does have a digital read out and once locked does not appear to move. It more then likely is me, I used the stock miter gauge and held the rails while I coped the ends using the fence as a guide I will get some kind of coping sled to lock them in place next time. Would it be better to use the rub collar when I cope the ends???

[David DeCristoforo]

http://www.daviddecristoforo.com/Misc/coping_jig.pdf

[Peter Quinn]

Would it be better to use the rub collar when I cope the ends???

If you are using a split fence and a miter gauge I think it is advisable to use a rub collar on the cope to set the tongue depth. The collars we use for 1/4" tongues are solid, not ball bearing collars, more like a spacer of proper diameter. Typically these come with the sets I think. For passage doors we use a solid fence backed into the cope stack that creates its own bearing surface. You have to create a curved relief on the back side of the fence and use a smaller diameter spacer to set the tongue thickness in this case.

My preferred option is to use a sled. Mine is similar to the one David linked, but in my typical fashion somewhat more complicated. I used a piece of 1/2" phenolic, ran a 3/4" dado parallel to the edge nearest the cutter 1/8" deep. The dado method insures that the leading edge is parallel to the miter slot and that the miter bar does not shift under load over time. The dado is stepped back enough to put the leading edge close to but not in contact with the cutter, as I want support but no contact with the phenolic.

Into the dado goes a 1/2"X3/4" miter bar, tapped horizontally with 8/32 set screws to take out any play. I drilled a pilot hole at the back right corner of the phenolic plate and used this to run an arc with a router that steps from 1/4" at the center to 3/4" on the bottom. Through this arched slot comes a 1/4" #20 bolt, another 1/4" #20 through the original pilot hole. These bolts hold the primary fence. This sled allows me to cope angles from 90 degrees to 45 with a quick adjustment. I also put a backer on the fence with t bolts and a t slot cutter for quick adjustments to that as well. A couple of heavy duty toggle clamps completes the thing. Cost me around $35 and took a couple of hours to design and build, but it works great. I use the in feed fence as a depth stop, setting it parallel to the miter slot and flush with the rub collar, I back off the out feed fence 1/8" or so as it is not needed with the sled.

I find using a miter gauge puts the fingers too close to the cutter for my comfort, and the sled improves both accuracy and safety. Hope this helps.

How do you like the PM2700?

[Bryan Cowing]

Shop Fox universal jig. I used to have a homemade sled and Destaco quick clamps to hold the stock. Found this jig at 1/2 price at a wood show a few years back. The oak block, with profile, on the right is a sacrificial piece to prevent blow out when cutting the right hand end of the rail. For the left end, change the block to a square edged block.