Carvex circle cutter problem

[SticksInTheMud]

I tried to use my Carvex circle cutter for the first time, when I almost immediately ran into a problem. As you can see by the attached photos, shortly after beginning the cut everything went wonky. The metal tape of the device buckled, but I don't know whether the device was pulling the blade off track, or vice versa. I tried cutting in the opposite direction and got the same result. It was far enough off track that the blade bent. I eventually used the device with a pencil to draw a circle and freehanded the cut (with a new blade) and everything went fine (I sanded to the line). Where did I go wrong?

 

[Gregor]

From the pictures I take it that you ran the saw without orbital motion (pendulum stroke selector at zero) and the blades (at least they look like that, a bit hard to see) are no-set ones - I think combining these two things with a high feed rate can most likely explain your result: that the kerf didn't follow the circle but went straight, putting stress on the blade (and even enough on the Trammel so it buckled, as you wrote). Another factor could be that you forgot to adjust the blade guide jaws so the blade had room to bend.

I would suggest to use a side set blade (to get a slightly wider kerf, so the blade body has room to turn - S 75/4 FSG or, for small diameters, a S 74/4 K) and adjust the blade guide jaws correctly. Possibly give the saw a little orbit (which will free the blade from the workpiece for the down motion, starting each cut fresh - you should test with a curve cut on a scrap what works best for you). Then feed slowly so the blade has time to cut away the inner (toward the circle jig) kerf face and turn, when you feed to fast it'll tend to go straight.

For circles the mentioned blades worked well for me. YMMV.

In case you don't have it:https://www.festoolusa.com/-/media/...nloads/manuals/carvex-ps420-jigsaw-manual.pdf

 

[peter halle]

One other thing that is that the trammel point should always be in the hole closest to the rear of the saw.  Page 16 of the supplemental manual linked to above.

Peter

 

[Holmz]

Are speakers going in there?
Or
Is it a new seat for the long drop?

 

[SticksInTheMud]

My thanks to you for your guidance. I've printed the suggestions for storage in the Carvex Systainer, will obtain the recommended blades if they're not in the Systainer, and institute the operational changes on my next circle-cutting endeavor. Holmz, the circle is a seat for a round stool I'm making for my wife. Thanks!