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Question regarding finishing on cedar lumber

The Dude

Hot Rolled
Joined
Oct 19, 2010
Location
Portland, OR
We're trying to improve some cedar lumber (1 1/4 x 4 nominal, 1 x 3.5 actual) processing that is used on an outdoor gardening product. The volume is increasing (you probably know why!) so the labor is becoming an issue. Basically, sanding is the bottleneck in this whole process (has to be cut/drilled/bored/sanded/stained). The boards form a flat frame and the ends of some cuts (straight 90 deg made on a chop saw) need to be a bit "bull-nosed". They currently do this with a fairly long horizontal belt sander since they also need to sand the long sides. Bottom line is it takes time and doesn't always match up perfectly.

Here's my question concern: I think routing would be a much faster and more accurate process for curving the top and bottom ends (and one corner) of the cut ends, followed by a quick rotary "flap wheel" sanding that we've verified can do the edge sanding much quicker and "good enough" over the belt sanding. I am not an expert router for various materials and was told that the cedar lumber can sliver-out/splinter a bit, even with carbide router bits. Can anyone give me a recommendation on improving that process so that a router could be used, or in there another process that could quickly and easily make the rounded corners as shown in the photo (note that the raw end is factory cut, not from the chop saw they use which would be finer-cut).

One other question: if a router would work (or similar tool), is there a company that could make a custom bit that would cut the top and bottom corner in one pass? The could also turn it 90 degrees to put a radius on the outside corner. Note that since this is for outdoor products that sit in a garden, they don't have to be "perfect" like a picture frame or a cabinet door. "Good enough" is what we need. No splinters, reasonably consistent process, etc.

Thanks,
The Dude

PXL_20210430_144442182.jpg
 
I suggest a roundover bit in a table router. I'd use a bearing bit, but you have to be aware that in soft material like cedar the bearing can leave a track if you push on it too hard. Using a router on the long edge with the grain will not give you much trouble if any on the blowout on the grain, especially if you climb cut, but the cross grain can if you aren't careful. You will need to cut cross grain first and possibly even put a backup board on it to keep from blowing out the edge.

Yes, you can get cutters to do top and bottom at once. The stock will need to be pretty consistent on thickness or you will be chasing the adjustment alot and not be saving any time. If you want top and bottom at once, I suggest using a shaper with a custom cutter that will cut both top and bottom profile, but also the edge as well. You'd have to start off with larger/wider stock to account for the edge removal. I bet if you do that, then you won't have to sand the edge or roundovers at all. To do the ends you may want a miter gauge or a fixture to hold it square. Depending on how long the parts are you may use it on the long edges too.

You can get custom ground knives for shaper heads from alot of sources. If you google top and bottom roundover bits, there are a bunch that pop up with the bearing in the middle and are adjustable.

To do the corner roundover, you will just need a standard bearing roundover bit, i'd put it in a second router table for just that op.
 
You can try talking to Fletcher Machine in North Carolina. They do all kinds of woodworking specials.

Have you been to any woodworking machinery shows ? There's some trick stuff out there ... won't help you right now but if they ever restart tool shows, you should go see.
 
A router bit can certainly tear out the material at the end of the cut, especially in end grain as you're doing.

A router table with a sled and sacrificial backerboard on the fence will help with the tearout.
 
I would head in the sanding direction versus the 'cutting' direction. Tear-out and burning will be your downfall using hand held routers while sanding is the better choice, especially for outdoor, not-so-fussy woodworking.

Stuart
 
Hey thanks guys, I will "experiment" with a small router table just as if it works it will be so much more efficient and consistent in shaping. Hopefully with your suggestions we can overcome any splintering.

The Dude
 








 
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