Making Curved Mouldings on a Shaper
General direction on the jig setup needed to run arched casings or other curved pieces on the shaper. October 4, 2007
Question
I need about 6 pieces of half round and curved casing for some shutters. The customer wants stain-grade cherry. Is it possible to make these on a shaper? I have a quality shaper with tilt (I have never used). I've read here about people making moulding with a tilt shaper, but it is not sinking in.
Forum Responses
(Solid Wood Machining Forum)
From contributor H:
If it's a small radius, you can do it on a lathe easier. If you don't have a lathe, sub it out. Copying a molding profile isn't that hard for a good turner. They can do some pretty big curves.
From contributor T:
No offense, but I think a lathe is probably not the machine the questioner should be looking to. He can do what he's looking to do on the shaper. You do need a feed, and some uninterrupted time to think out your jig process. Rather than give you all of the details on how to do this, the better thing for you is to go into it with some general direction instead. This will enable you to better think through your process, and get your creative juices flowing. One tip I will give you is to make a good template with masonite, and then cut your plug using a straight cutter and bearing on your shaper. Then you can figure out your radius jig rather easily.
From the original questioner:
I am looking at window casings. The half round window is 50" and the curved 1/4 circle is 60", so that would make the curve about 20', so I would assume the lathe is out. Contributor T, this is the sort of thing I am talking about. I have heard it is possible, but not sure where to start. I do mainly simple case goods. I now have a customer that wants me to put matching window treatments in their kitchen. I have always stayed away from curved products because of my ignorance. If I can come up with something, I can always add curves into my cabinets.
From contributor T:
Start with a template of the outside of the radius. Use 1/4" masonite for this. Band saw/jig saw it to shape, then carefully sand it so there are no flat spots or humps. Remember that the shape of your template will be the shape of your molding. The 1/4" material will make it easy to sand to perfection. A disk sander makes this easy. You can get a disk for your table saw if you don't have a stand alone unit. Next, you need a sled. This is a device to clamp your template into so you can safely guide your template and plug along a bearing.
There is a great cutter to use in the Grizzly catalogue, at www.grizzly.com/catalog/2007/Main/496
The bearing is the page before. You need the cutter, a 4" bearing (shown on the page before) and any bushings you need to convert to your spindle size. (*Do not buy the system head with the bolt in knife shown on the same page. They are too aggressive and unstable in my opinion. I lost a finger years ago using one.*) You may need a new spindle as well if you want to get a cutter taller than your existing spindle. A sled is shown here as well. This will give you an idea of what I'm talking about. Once you have cut your plug by using your template and a sled, you can use the same sled for molding your part.
From the original questioner:
Okay, I see what you have going here. I have all the equipment to do raised panel doors. I have template, flushing bits, bearings, sled, etc. I am looking to make casings to cover an arch window. I need to shape the face to the moulding. If it laid on a table, I need the top of the wood. Not the edge, as I would rails.
From contributor M:
What you need to do is lay out the radius on your cherry material and saw the curve out. Save the scrap piece from the back of the casing. This will be your cradle that you will screw to the fence of the shaper. I hope you have a power feeder. You need one. I'm assuming that you have a knife/cutter for the casing profile that will fit on your shaper. Once the cradle is screwed to the fence, you will have to adjust the height and depth on the shaper. You will probably need to fix some piece of scrap the thickness of the depth of the profile cut to affix to the upper side of the shaper fence to keep the casing piece from twisting after the cut. The power feed will want to push it flat to the fence. If you have some time and material to play with, try it out. But for a stain grade cherry casing, I think I would sub it out. Try some paint grade material first.
From the original questioner:
Ah, I am starting to get the picture. Thanks a bunch.
From contributor J:
We have done that a few times. Like stated above, the inside radius of your cradle (clamped to your fence) matches the outside radius of your moulding blank. Have your power feed tilted downward and your blank will slide right through. Make extra setup pieces.
From contributor T:
Once you do this a couple of times, you will get used to it, and it will open up a whole new world for you. It will put you a notch above most of your competitors.
