Saturday, January 16, 2016

Jigsaw circle cutting jig







How to cut wood circles? Most woodworkers will have to cut circles, partial circles or arcs from time to time. Cutting circles can be done many different ways using many different tools. It is nice to have plenty of options. 

    For example you can use a:           
                   

  •  table saw
  •  bandsaw
  •  jigsaw
  •  router 
  •  handsaw
  
For some of these tools you can cut free hand by following a outline but this way is not very nice. 


To be precise a jig would work best. 



              John Heisz shows us how to make perfect circles on a router with his  circle cutting jig. 





            I also made a  Router circle cutting jig  using a similar setup I am about to show you, but it will be updated and better.                   


       




  
I wanted to try something different so I thought I would try a jigsaw. This jig will be very simple to make and you will be able to make small and large circles even up to 4 feet.

In this article I will show you  how to make the jig for the jigsaw and how to use it.








Building the pivot dowel

I first started with the dowel, this will be for the the threaded rod. I used my bandsaw sled to cut a 32 cm DIA dowel 45cm long. 




A hole was drilled through the centre of the dowel for a coupling nut. To do this safely I used a v-block to keep the dowel straight and a push stick for support  while I was drilling it.  




A coupling nut was inserted into the dowel. First it was tapped in a bit with a hammer then a vise was used to push it in all the way. Doing it this way will help to prevent splitting.




I bought various types of snaps and tested them out. 


They are available at Home Depot , and are inexpensive costing under one dollar each.
  
Screw snaps and Stud snaps will both work depending on your project. The screw type will screw into a piece of wood while the stud snaps should be glued onto a wood disk then with two sided tape it can be placed onto your work surface and when you remove it later there will be no marks.







A hole is countersunk in the dowel and this will be for the stud snap. By countersinking the snap into the dowel it will sit better on the workpiece. I used some CA glue and a small Robertson screw to put it together. 







 Building the Jigsaw base                                                                               

  1/4 inch Baltic birch is used for the base of the jigsaw. The jigsaw was placed onto the wood and the bottom was outlined and ready for cutting.
                      






 I used a piece of oak for the sides. They were cut on the bandsaw and I  knocked off the edges which made it look better. 










The jigsaw was placed on the board and the sides are carefully clamped tight against the jigsaw sides. This will help make a nice tight fit.






I removed the bottom soleplate off the jigsaw. It was very easy since it just snapped on.




Making a long drill bit

I did not have a drill bit long enough to drill through the base for the hole for the threaded rod. It had to go through both sides to make it line up exactly. To do this I made my own bit out off a smaller piece of threaded rod I had lying around. 

I just cut the piece about 8 inches long and put it on my belt sander and ground the tip until it made a sharp point. This did the job quite nicely. After the pilot hole was drilled with the new bit I used a regular  drill bit to match the right size for the large threaded rod.















Threaded rod in the dowel. The dowel and coupling nut will turn very quick on the threaded rod and give you an accurate measurement fast.






Here is a shot of the rod bolted to the side of the base. One nut on both sides is enough to keep it secure.








A couple of disks are cut out using a hole saw. They can either be taped to the workpiece or screwed down.  







Conclusion

 Most woodworkers will have to cut circles or partial circles.  This handy jig will work for most jigsaws. The snaps make it simple to use and the threaded rod and dowel makes it simple to adjust. It can be adjusted to as long as you want.
(as long as your threaded rod).

If you build one let me know how it goes or if you have another design please let me know how yours works. Good Luck!




  








 See also:


Cutting groves                 Quick stop block             Make a dowel station
                                                


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