Milling Radius Crown Moulding
For your problem, I am assuming that you have a set of cutters that you can mount on the tilting arbor. If this is a normal size cutter (3.5" - 4.5") this is a large cut to take in one pass. And I would suggest you do several passes. You would need to build your jig so that it is a self-contained radius jig, meaning it would hold your piece and rotate 90º around the cutter because you cannot use a bearing when the arbor is tilted. Maybe you could use a pin, but that seems unlikely as I think it would get in the way of the cutter head. I guess I am suggesting that you go by my first description with a pair of cutters and some patterns. It would be much safer in my book.
From contributor B:
You can actually use the fence to set your depth of cut, provided it is an outside radius. One thing is to make it extra long. You will most likely get snipe on the ends and it is better to be long than to have to start over. I would be interested to see your profile. I have done several of these in my day and some are easier than others.
From contributor C:
Many people run curved crown on a tilting shaper. It is much safer then on a vertical spindle shaper as you have a lot less knife projection. I once had a cone shaped moulding head made for our vertical spindle shaper so that we would have less projection of the tool steel. It worked well and was safer, but was still a relatively hazardous operation.
The safest way to run curved crown is on a tilting head moulder such as the ones by Fortis, Steggher and Mikron. Assuming that you aren't interested in purchasing a new machine for a single moulding run you'll have to work with the tilting spindle shaper. As contributor B stated you can use your fence as a guide for outside curved crown. That, or a bandsawn curved fence, will keep the material in the correct orientation to the cutterhead.
Inside curved crown will require the bandsawn fence though. You'll have to be careful to line it up correctly though as there is only one correct wood to spindle orientation position. If you line up off center you'll have the wood coming in from the side of the tilted spindle rather then having the spindle leaning over the wood. A power feeder is absolutely required as well.
From contributor D:
As the previous post mentioned, I always use a curved fence that matches the curve of my crown. I would never use a rub collar with the spindle tilted. A shaper kickback with a tilted spindle can be quite catastrophic to you and the machine. Each job may require special set-ups to help guide the work around the curve while using a powerfeeder. Take small cuts until you get the feel of it. I've cut some very large profiles that have taken over twenty passes to do. You can also remove the majority of the waste on a bandsaw with the table tilted prior to shaping.
From contributor E:
Have a machine shop make a 45 degree sleeve that presses over your guide bearing. Then when you tilt the head your guide bearing will be plumb to your MDF template. Trim most of the solid blank away on the band saw with the table tilted. It's all still pretty scary stuff! A Mikron shaper could pay for itself pretty quickly with a couple of good sized crown jobs.
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