How do I smooth out curved cuts?

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Forum topic by Mary Anne posted 10-17-2010 06:43 PM 9259 views 2 times favorited 28 replies Add to Favorites Watch
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Mary Anne

1058 posts in 4261 days

10-17-2010 06:43 PM

Topic tags/keywords: question

I am working on a special gift for a friend (Wood Mag Dancing Clock) that calls for some smooth curved cuts and I end up with ripples instead.

I am getting pretty good, but my bandsaw and I are not a perfect team yet and I end up with kerf lines and a few little jogs where I missed following the line exactly… nothing too drastic. After the bandsaw, I take it to my Rigid Oscillating Spindle Sander to smooth things out, but the edges end up feeling wavy.

Should I be able to get the smooth curves I want with the bandsaw and OSS? Maybe I am not using the OSS properly? Or is there something else I need to do? I hope someone can steer me to a way to get the curves smooth and consistent.

Thanks!! It is so great to have the many experienced woodworkers here to turn to when I run into a problem.

28 replies so far

View grizzman's profile


7836 posts in 4356 days

#1 posted 10-17-2010 07:02 PM

yea when it comes to curves…there a little tricky…i know when im doing something like that i can have problems too…are you making sure your wood is totally flat when you use the oss…, that might be one thing…the other is making sure your blade is good and sharp on the bandsaw, so that you get good flow when your cutting the curves….i dont know if any of that will help…but maybe someone who knows more on it will help too…good luck mary ann…....hows that room of yours doing…did you get the hot tub in there yet…grizz

-- GRIZZMAN ...[''''']

View Abbott's profile


2570 posts in 4356 days

#2 posted 10-17-2010 07:04 PM

Diet and exercise :)

-- Ohh mann...pancakes and boobies...I'll bet that's what Heaven is like! ♣ ♣ ♣ ♣

View Abbott's profile


2570 posts in 4356 days

#3 posted 10-17-2010 07:05 PM

I have found that an oscillating spindle sander is a great aid…I have also used dowels of various sizes wrapped with sand paper. That interior you are doing looks real nice :)

-- Ohh mann...pancakes and boobies...I'll bet that's what Heaven is like! ♣ ♣ ♣ ♣

View tdv's profile


1203 posts in 4123 days

#4 posted 10-17-2010 07:09 PM

Mary Anne Two ways I use to get smooth curves are make a 1/4” ply or MDF template (it’s easier to refine smooth curves on thinner material) & then stick the template to the work piece with doulble sided tape & rout with a bearing guided profile bit. Or 2) use a belt sander to refine the largest area of the curve & finish the tightest areas with the spindle sander. One other little tip I find works well for me is when you are trying to level out bumps with a spindle sander passing your work from right to left ( assuming your sander rotates anti-clockwise)only accentuates the flaws. If you get a good grip of the work piece & lightly yet quickly traverse from left to right It seems to hit the bumps & smooth them more evenly. This is like climb routing so be careful your work is travelling in the same direction as the sanding drum. Have a little practice first I’ve never had a mishap with this method but just take care & be gentle. hope this is useful to you

-- God created wood that we may create. Trevor East Yorkshire UK

View randi's profile


43 posts in 3873 days

#5 posted 10-17-2010 07:11 PM

Yep, oss here, keep the drums nice and clean and feed the work to it with a smooth action, and you can smooth out pretty much anything very cleanly.

Theres always good old fashioned hand sanding as well…always fun.

-- "A computer lets you make more mistakes faster than any invention in human history - with the possible exceptions of handguns and tequila." ~Mitch Ratcliffe

View JJohnston's profile


1622 posts in 4344 days

#6 posted 10-17-2010 07:20 PM

Try using the belt, or some other flat sander, for the outside curves as much as practical. Trying to sand outside curves with an outside curve (sanding drum) just makes it harder.

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

View Abbott's profile


2570 posts in 4356 days

#7 posted 10-17-2010 07:23 PM

Both good points you guys! I and others were only thinking of inside curves and only gave up half of our techniques.

I keep one of those small combination rasps with four sets of teeth in various roughness’s handy. Sometimes it sees a lot of use.

-- Ohh mann...pancakes and boobies...I'll bet that's what Heaven is like! ♣ ♣ ♣ ♣

View BarbS's profile


2434 posts in 5138 days

#8 posted 10-17-2010 07:25 PM

Mary Anne, you don’t say how large the curves are you are trying to cut, but one method on the band saw is to overlay your table with 1/2” or 3/4” ply in a larger sheet, cutting into it with the blade, then mark the corners underneath and attach blocks to hold it in place. To this, now zero-clearance tabletop, you can attach jigs. In your current problem, a pin to swivel the workpiece through the blade (how tight a curve? use the appropriate blade.) If it is a large arc, as for a rocking chair, your center pin may have to sit off the table out in the nether lands of your shop somewhere, and a router template may be the answer. Either of these would make your sanding job easier Several ways to do it!


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Mary Anne

1058 posts in 4261 days

#9 posted 10-17-2010 07:30 PM

Thanks, guys! Sounds like I am on the right track with the OSS, but maybe need to refine my technique and practice to improve my skill.

Thanks for the different suggestion, Trevor. Now I have a reason to try something else I’ve never done before… template routing and climb sanding.

It took 10 big guys to tote the hot tub (it’s a huge 7-person tub) from my garage to the new room, but it’s in there! Next nightmare is dealing with the mess the electrician who thought “close was good enough” left behind. Still got a couple more ceiling sections to go with the T&G, but the end of the job, on the interior at least, is in sight. Thanks for asking.

View a1Jim's profile


118161 posts in 4630 days

#10 posted 10-17-2010 07:32 PM

Hey Mary Anne
I agree that a OSS is a great tool and it works great . I’ve also used a pattern makers file and a Japanese saw file.
If you want to make more than one of some of thing or your not having success with your OSS a pattern and a flush trim router bit works well too, As Trevor suggested.
After some more practice or changing drum size I’m sure you can make the OSS work too.


View Mary Anne's profile

Mary Anne

1058 posts in 4261 days

#11 posted 10-17-2010 07:35 PM

More great answers. Thanks! Maybe I can hit some areas of the outside curves with the belt sander. Nothing looks drastically off enough to go at it with a rasp, but heck, I have one so I’ll see what it does. :)

I hope Otto doesn’t mind me using his as an example, but this is what I am working on:
Click for details

View Spoontaneous's profile


1340 posts in 4383 days

#12 posted 10-17-2010 07:38 PM

I’ve never used an OSS before but I have done a LOT of sanding on curves using a spindle/drum type sander (Usually on a drill) and what I found to be true is that the bigger the drum/spindle the easier it was to avoid bumps and ridges. I’m talking inside curves. On the outer, if it is a manageable piece, a belt sander (a free-floating one esp.) can be used with great results… just keeping in mind long and light and consistent strokes.

-- I just got done cutting three boards and all four of them were too short. (true story)

View lew's profile


13332 posts in 4808 days

#13 posted 10-17-2010 07:39 PM

Mary Anne,

When using your Oscillating Spindle Sander, try to use the largest spindle possible for the area you are sanding. That will tend to minimize the waviness. Also, after you get the sanding just about where you want it, move the piece quickly back and forth across the spindle. This will help to even out the little wavies.

Hope this helps,


-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Dennisgrosen's profile


10880 posts in 4168 days

#14 posted 10-17-2010 07:47 PM

Mary Anne
try the old school metode …LOL
both rasps and spokeshaves can do the trick with inside and outside curves
but with this one I will surgest a compass plane

take care

View Mary Anne's profile

Mary Anne

1058 posts in 4261 days

#15 posted 10-17-2010 07:50 PM

You hit on my problem—- SPEED! It looks like I was going way too slow. I was easing the piece along the spindle trying too carefully to follow the line, and that is what was causing the waves. Once I sped up and whipped it past the spindle a few times, everything smoothed out nicely.

Thank you all so much!!

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