Troubleshooting Cut Quality on Door Profiles

      A cabinetmaker's knives are wearing out too quickly. The discussion leads into various aspects of door profile machining. September 17, 2008

I finally upgraded to using a shaper for my doors a year or so ago. Since then I've done a handful of kitchens with each one requiring different cutters. I'm now at the point where I'm using a set for the second time and I'm running into problems. Originally I ran all the parts through using a climb cut and the results were pretty good. Now when I'm running parts through, the quality of cut is very poor. Basically scalloped along the whole length. Also the cutter was pushing the pieces away from the fence instead of cutting clean.

I reversed the setup and ran the parts straight through (non-climb cut) and the finish was much better, except I've got tearout along the edges of the groove. So at this point I'm thinking the cutters are just dulling. Fine, except this is only the second kitchen I've done with them!

How long do your cutters usually last? If I upgraded to 1-1/4" cutters, could I expect better life and/or quality of cut? The cutters are made by LRH, which I believe are pretty decent quality.

Do you cut your full profiles in one pass or two passes for clean cuts? I've been cutting in one pass. If I run two passes I'm sure I can get rid of the tearout, but then I'm using a lot more time.

I'm currently using a 5 hp, 3ph Powermatic 27 with 3/4" spindle for door parts, with a 1 hp feeder. I'm using almost all soft maple for parts and running my feeder at 13 ft. min.
I can easily pick up a 1-1/4" spindle for it, I just figured since I only use this machine for doors, it would be overkill. I have 2 other shapers for miscellaneous stuff, so am not worried about not being able to use my cutters anymore. Just didn't think a bigger spindle was necessary... Is it?

Forum Responses
(Solid Wood Machining Forum)
From contributor M:
The advantage of having a 1 1/4" diameter spindle is being able to run larger diameter tooling, which will give you a better cut, plus there is a much better selection of tool profiles. As for your tearout along the groove, are you removing at .030" when running your sticking profile? Without that, you'll always have tearout issues. I use a finished 2 1'2" rail and stile and mill my parts to 2.53" in order to get that. I assume you're also coping .030" off your ends? Most cutters are designed to have the ends trimmed. As for climb cutting, I've never had to do it and I don't think I want to unless my back is really up against the wall. Climb cutting will dull an edge faster as you're getting more of a scraping action rather than a cut, but it should have held up longer than what you're getting. Try removing a little more material on your sticking cut and see how that works.

From the original questioner:
Thanks! Because I haven't been able to get perfect cuts on my profiles every time, I've been running my parts oversized and trimming to width after. That way I can make an extra pass or two when I need to clean the profile up. That being the case, I haven't been too concerned in the past with the exact amount of material removed. As set up now I'm removing about .015. When I do the copes it's about the same. Tomorrow I'll try removing a little extra, but I'm guessing I'll get an increase in tearout when I do. If the larger cutters really give a noticeably cleaner cut, I may just replace this set as opposed to sending it out for sharpening.

From contributor L:
What diameter cutter are you using now? I have a cope and stick cutter that I use and I never get chipout on any species. I remove 1/16" on the stick cut and 1/64 on the cope. I do run them slower though. I think I run mine at 4 meters a minute. Maybe slowing your feed rate down would solve your problems.

From contributor G:
I run only 1 1/4" cutters, but I get a lot more than one kitchen out of a set. You didn't say what species you were using. I find taking 1/16" of both stick and cope works fine for me, but if I feel the need for climb cutting, I use a "trap" fence. A straight cutting of 1/4" ply clamped the width of the required stile away from the cutter, then angle the power feeder into the new fence (you don't use the shaper fence at all, but it is still around somewhere).

A lot of sawdust flies out the profile that you are cutting. Because of that I normally use the same system, but I feed from the other way, into the cutter (angling the feeder into the trap fence). Works for my 1 1/4' bore cutters.

From the original questioner:
Contributor L, I just measured and the cutters are about 3" in diameter. As far as speed, I'm not sure about the exact conversion, but I think 4 meters per minute would be pretty close to 13 ft. per min., wouldn't it? That's the second slowest speed on my feeder and the slowest setting is about half that and I wouldn't want to try getting anything done at that speed.

Contributor G, I'm using mostly soft maple for my door parts as most of my jobs are painted. I think I'll probably pick up a 1-1/4" spindle with a new set of cutters and give it a try.

From contributor L:
Sorry, I thought I read 13 meters a minute. You are running at the same speed as I am and your cutters are about the same size as mine. I don't think you will be solving your problem with a bigger spindle. Have you tried taking more stock off, like 1/16" instead of .015"? Could be your break out is deeper than the .015".

From contributor A:
Are you running at 7k or 10k? Taking a minimum of 1/16th helps. On some woods taking 1/8th works even better. Cedar, redwood, and other straight grain woods need the extra 1/16th typically.

From contributor J:
I think your cutters are blown from the climb cutting, and in need of a fresh sharpen. I size my material at least 1/8" over net size and remove it in one pass. You should run your material between an opposing fence and the cutter, pushing towards the fence with the feeder, to ensure your stiles are exactly the same width and minimize chatter. I have the Weaver sticking plate that makes width changes quick and easy. The larger diameter cutters help a lot with tearout and feed speed. You might look hard at insert tooling if you do enough to justify the setup.

From the original questioner:
I'm currently running at 10k, but I guess I'll need to drop that once I upgrade to the newer (bigger) cutters. Contributor J, I think you're right. I ran my copes last night and they seemed to cut fine. I think the climb cutting wore the stick profiles out prematurely. So the consensus is basically to take off more material, run the pieces between a fence and the cutter, and use a larger cutter. I'm not going to try it out now, as I believe these cutters are too dull, but I'll be running another batch in a week or so and will give it a shot.

Thanks again for the responses. Sometimes being a one man show works against you as there's nobody more experienced to go over and ask a simple question. I appreciate having this site to be able to ask those questions.

From contributor A:
Does climb cutting cause more wear on cutters? Maybe one of the sharpening guys will chime in on this thread. It makes no difference in cut quality running off the fence or an outboard sizing fence. The sizing fence is nice because it causes no snipe as well as cutting to an exact size.

From contributor P:
I have found that the larger diameter cutters usually give a better finish. Obviously, the larger iron is 1 1/4. I have spent thousands of hours running shapers and cutters of all profiles and sizes. What I have found with the smaller cutters 2.5 to 4.0 diameter, is excessive tearout. The reason, I feel, is that the cutting edge, for a given depth of cut, exits the wood at a steeper angle. The larger diameter lets the cutting edge leave the wood at a shallower angle, thus it is like tricking the wood into thinking it's a smaller cut. Think of how a router tears out a small cove and how a shaper will not. Huge difference in diameter.

I accumulated some panel raising heads that are over 10 inches in diameter and have only a 2 in cut depth. These things cut so smooth at a full depth in any wood, edges so crisp they will cut you. I use LRH Executive line with no problem - they make nice stuff.

From the original questioner:
I just ordered a new Freeborn set for the 1-1/4" spindle I also ordered today. The new set is only 4" in diameter, which is larger than the previous set, but not by much. Do you also use large diameter cope and stick sets? I looked around and 4" was the largest I could find, including the LRH website. I'm guessing if I wanted something larger than that, it would be a custom set. Not sure if I want to invest that much money in a single profile right now. Guess I'll see how the new cutters work and go from there.

I also checked out some insert tooling and it looked okay cost-wise. It was actually cheaper than the set I bought. But unlike a cope and stick set, I wouldn't be able to swap cutters to do glass doors.

From contributor B:
I use Freeborn cutters, however LRH makes equally nice products. I use 1" spindles with 1 1/4" cutters T-bushed. I keep each of the several profiles I have set between bushings up so that bit changes are simply removing one set of cutters and re-installing the other. No change in machine settings is required. I leave my stiles wide and rip for width after the stick is cut.

From contributor P:
4.0 should be fine. Freeborn makes a good product with the proper cutting geometry. If I had a choice I would push for 5 to 5.5, but that would be a custom and why pay more unless it's absolutely proven to be better for your situation.

From contributor R:
I use Freeborn shaper cutters, the Mini-Pro (tan-tung), which are 2 5/8" in diameter. I was getting tearout along the groove when feeding into the cutter. I now climb cut with a power feeder and a featherboard to hold the stock tight to the fence. I have absolutely no tear-out and do not get premature wear on the cutters. I replaced the top straight 3/8" cutter with a ball bearing and do not get any snipe. Been shaping like this for years. I have two 1 1/2 hp shapers dedicated to the stiles and copes, which eliminates setup time. I also use a homemade coping sled for the copes. (Made from high density polyethylene and a piece of wood fastened at 90 degrees to the fence and a hold-down clamp.) Don't think it is necessary to invest in larger diameter cutters.

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