Cutting circles on a Bandsaw? Any good?

[Alan Tolchinsky]

Hi All, A friend of mine told me he uses his bandsaw to cut circles. Since I've always used a router with trammel arm I wondered which gives the smoothest result. I would think the router does but is there any advantage in using the bs for this? Alan in Md.

[Lou Morrissette]

Alan,

I use my BS to cut circles many times and get a smooth cut by clamping a "trammel" type arm to my table.

Lou

[Jim Becker]

The principle behind cutting circles on the band saw is essentially the same as with the router, except the material moves in the arc and the tool stays stationary. There are a number of circle cutting jigs that have been featured out there, including Norm's on NYW. It's pretty simple...a table extension that is level with the band saw table and a pivot point that engages the material to be cut, usually a dowel or metal pin that fits in a small hole you put in the bottom of the workpiece. Just remember that the cut line begins at the front of the blade, not the middle, when you are making small diameters!

[Alan Tolchinsky]

The principle behind cutting circles on the band saw is essentially the same as with the router, except the material moves in the arc and the tool stays stationary. There are a number of circle cutting jigs that have been featured out there, including Norm's on NYW. It's pretty simple...a table extension that is level with the band saw table and a pivot point that engages the material to be cut, usually a dowel or metal pin that fits in a small hole you put in the bottom of the workpiece. Just remember that the cut line begins at the front of the blade, not the middle, when you are making small diameters!

Hi Jim, I was wondering if the router is your preferred method of circle cutting? It seems with the bs there would be a lot more clean up. And we all hate that of course. :) Alan

[Doug Shepard]

Which is smoother all depends on how well your wood is cooperating. In general the router will leave a smoother cut. But you can run into difficult or changing grain direction as you're going around the piece and can end up getting tearout from the router that you won't get with the BS. The big trick with the BS is to keep a constant feed and not let the piece stop moving as you rotate it. I've done both and have had good results and not-so-good results from both methods. I've finally settled on cutting 1/32 to 1/16 bigger, then spinning the piece on a pivot point up against my disc sander to get it down to final diameter.

[Jim Becker]

Hi Jim, I was wondering if the router is your preferred method of circle cutting? It seems with the bs there would be a lot more clean up. And we all hate that of course. Alan
I use a router and a MicroFence for smaller circles but would use the band saw for large things where it would be easier to move the material rather than the tool. There is no, one, right way to do this. Check out the new issue of Fine Woodworking (April 2005) as there is an interesting table article where the author uses a router and a tramel for a lot of the milling of curved parts for the base. He has those parts fastened to an inexpensive and disposable substrate (MDF I believe) so that he can do further straight cuts on the TS after the curves are milled. Great techniques to learn from.

[Alan Tolchinsky]

I use a router and a MicroFence for smaller circles but would use the band saw for large things where it would be easier to move the material rather than the tool. There is no, one, right way to do this. Check out the new issue of Fine Woodworking (April 2005) as there is an interesting table article where the author uses a router and a tramel for a lot of the milling of curved parts for the base. He has those parts fastened to an inexpensive and disposable substrate (MDF I believe) so that he can do further straight cuts on the TS after the curves are milled. Great techniques to learn from.

Thanks Jim, I'll check out that issue. I just got it.

[Norman Hitt]

Alan, I posted you a pm reply, but your box is full, so you won't get it til you empty some of the box. Norm

[Alan Tolchinsky]

Alan, I posted you a pm reply, but your box is full, so you won't get it til you empty some of the box. Norm

Thanks Norm; I'm cleaning the box out now. Alan

[Richard McComas]

Hi All, A friend of mine told me he uses his bandsaw to cut circles. Since I've always used a router with trammel arm I wondered which gives the smoothest result. I would think the router does but is there any advantage in using the bs for this? Alan in Md. I cut most of my larger circles on the table saw. If your interested in this the link below will take you to a thread on the woodweb forum where I posted a photo of this and some responses from other members. Read the thread and it will explain how it's done.

[Alan Tolchinsky]

That's interesting! Never thought you could cut a circle with a table saw.

[Keith Christopher]

Well as long as you maintain a tangent to a plane and rotate the plane you will generate a circle. (I used tangent for clarity because it would actually intersect a plane and as it became a circle become tangent to it. ) In this photo if the line is a saw blade, and you rotate the stock, the contact point (P) is the bladeyou will generate a circle.

[JayStPeter]

Alan,

I've always used a router. My various router trammels got lost in my last move though :mad: . My feeling is that the router gives an edge that just needs minor sanding before finish. I can't see MY bandsaw giving an edge quite that smooth. YMMV as your BS is a little nicer than mine. But, I still imagine there would be a little more work involved.
To make my trammels, I drew concentric circles with diameters increasing by 1/16" per circle in my CAD program. I printed it out 1:1 scale. Using a router base it is easy to center it on these circles. For small circles, I leave the printed circles on the bottom and drill holes for a pin directly into the MDF base. I can use the circles to gauge how much to tweak the circle if I need something exact. I've done a lot of flush mounting of tweeters this way.
Before I moved, I had three trammels. The first was a 10" diameter circle that I drilled holes in to make smaller circles. The second had a slot and screw that I could adjust for circles up to about 24" in diameter. The last was a simple base that I could bolt a piece of 3/4"x2"xNeeded' to with a piece that I could position on the extension and clamp into place which had a 1/4" bolt through it as a rotation point. I used it to make arcs and cut a large square tabletop round for a friend. Many of the arcs needed around a 10' radius, so I would take a 12' 2x12 on some sawhorses and clamp everything up to that.
I'll remake the trammels as needed and make them a little higher quality this time. I also plan to try and build in some DC optomization for the OF1400.

Jay

[Mike Stanton]

I cut most of my larger circles on the table saw. If your interested in this the link below will take you to a thread on the woodweb forum where I posted a photo of this and some responses from other members. Read the thread and it will explain how it's done.


I am very interested please send me a pm thanks Mike :confused:

[Alan Tolchinsky]

Alan,

I've always used a router. My various router trammels got lost in my last move though :mad: . My feeling is that the router gives an edge that just needs minor sanding before finish. I can't see MY bandsaw giving an edge quite that smooth. YMMV as your BS is a little nicer than mine. But, I still imagine there would be a little more work involved.
To make my trammels, I drew concentric circles with diameters increasing by 1/16" per circle in my CAD program. I printed it out 1:1 scale. Using a router base it is easy to center it on these circles. For small circles, I leave the printed circles on the bottom and drill holes for a pin directly into the MDF base. I can use the circles to gauge how much to tweak the circle if I need something exact. I've done a lot of flush mounting of tweeters this way.
Before I moved, I had three trammels. The first was a 10" diameter circle that I drilled holes in to make smaller circles. The second had a slot and screw that I could adjust for circles up to about 24" in diameter. The last was a simple base that I could bolt a piece of 3/4"x2"xNeeded' to with a piece that I could position on the extension and clamp into place which had a 1/4" bolt through it as a rotation point. I used it to make arcs and cut a large square tabletop round for a friend. Many of the arcs needed around a 10' radius, so I would take a 12' 2x12 on some sawhorses and clamp everything up to that.
I'll remake the trammels as needed and make them a little higher quality this time. I also plan to try and build in some DC optomization for the OF1400.

Jay


Jay, what you say makes sense to me but I don't think a bigger saw necessarily gives a better cut. It all depends on the blade, I think, but a bigger saw might make it a little easier. I've only used the router method and like it except for the mess. How come one of the nicest tools in wood working makes the most mess! It just ain't right!:)

[Jim Becker]

I've only used the router method and like it except for the mess. How come one of the nicest tools in wood working makes the most mess! It just ain't right!
The "right" router deals with that quite well...but like anything, ching...ching... ;) When I last used a trammel, I used my PC router. In the future, the black and green ones will get the nod and there should be little dust compared to the other router(s) in my arsenal.

[JayStPeter]

Jay, what you say makes sense to me but I don't think a bigger saw necessarily gives a better cut. It all depends on the blade, I think, but a bigger saw might make it a little easier. I've only used the router method and like it except for the mess. How come one of the nicest tools in wood working makes the most mess! It just ain't right!:)

Not the size, but the "smoothness". I'm assuming that your MM MUST make smoother cuts than my similar sized Grizzly :D


The "right" router deals with that quite well...but like anything, ching...ching... ;) When I last used a trammel, I used my PC router. In the future, the black and green ones will get the nod and there should be little dust compared to the other router(s) in my arsenal.

Right on, I'm not bummed about the loss of my trammels anymore. I'd have to make new ones anyway.

Jay