Router and cutting circles

chrissy said:

I am very new and I haven't bought a router yet. I just do hobby and craft projects. I have to cut alot of circles and I want to get a router that will be able to have the Jasper 400 circle jig. Does anyone have any suggestions for me?? I could use help and more help.
Thanks
Chrissy

Click to expand...

I think I just posted to another request of yours about routers...... Anyway depending on how many holes you are doing and how much adjustment you need to have or are you sure about the Jasper jig?? You can also look at circle templates that you can purchase or make yourself, especial if the holes are smaller dia. I personal don't have a circle jig (yet) but I make my own as needed, they are simple to do.

Now more about the router. If you do a lot holes you will most likly want to look at a plunge router as this will make it a lot easier. You will also want to get some bits designed for plunge routing. Yes you can use fixed base routers but it is best to do the job with a plunge router. My general feeling would be to look at a comb package, fixed and plunge bases and the motor......

Since I see you just joined the forum let me say welcome! If you care to use the Introductions to tell us more about you and or your router projects that would be nice.

Ed

Circle cutting jig

This is what I'm using, found it in the web


The jig is made from a piece of 1/2" Lexan A fixed 4" 6/32 round head machine bolt turns to drive a 6/32 coupling nut along a groove. A 1/8" roll pin projects from the coupling nut through the bottom of the groove providing an adjustable pivot point. One rotation of the machine bolt via a second coupling nut double nutted at the end moves the pin 1/32", translating to a 1/16" adjustment to the hole's diameter.

Plans

I cut the plastic on my table saw to be exactly as wide as the base of my router.



Then I found the center point and used a spade bit to bore a 1" hole at that point. The length of the plastic was governed by the longest round head 6/32 thread bolt my hardware store could supply, 4". I sawed the Lexan so that when the head of the bolt rested on the edge of the 1" hole, about 3/4" would protrude past the short edge. I also drilled and countersunk holes for the screws to attach the jigs to the bottom of my router. Don't forget to pick up some longer screws for attaching the jig to your router!

I then routed a 3/8" wide groove 3/8" deep with a 3/8" bit from the edge of the Lexan to the center hole. I do recommend making multiple passes and using a router table with a fence. . I followed by changing the bit to an 1/8" and routing a 'closed end' slot 1/4" in from the ends of my 3/8" pass. Leaving the fence in place while changing bits makes the slot 'dead on' center.


End View
Top view




To complete the fabrication of the Lexan component, I used a small drill bit to make 'dimples' on the sides of the 3/8 groove at both ends. I did this to improve the adhesion of the epoxy used for assembly.

The next part to be fabricated was a 6/32 coupling nut. Coupling nuts are made to join threaded rods and, in this case, I used one that was 1/2" long. I threaded a scrap bolt through my nut then drilled a 1/8" hole halfway through the nut, the scrap bolt serving to protect the threads.


Coupling nut

Roll Pin


After drilling the hole, I threaded the scrap bolt further into the nut and then hammered in a 1/8" by 1/2" roll pin. A 'roll pin' in cross section looks like a C. The opening running the length of the cylinder allows a force fit, the pin retained by friction.

I took two 3/8" diameter x 1/4" nylon spacers and used a small drill bit to 'dimple' the outer surface of the nylon to improve the adhesion of the epoxy. The center holes of the spacers are only slightly larger than the diameter of the bolt.

I took my 4" round head bolt and slid (in this order) a #6 washer, a 'dimpled' nylon spacer, the 'pinned' coupling nut and the other 'dimpled' 'spacer.

Then the stove bolt assembly is attached to the Lexan by epoxying the spacers, each spacer fitting into the 1/4 x 3/8" area at the ends of the 3/8 groove, the roll pin projecting through the 1/8" slot. If I were build another, I might try some teflon pipe tape on the threads to prevent any epoxy adhering to them. On this model, I cleaned up my slight sloppage with the tip of an exactotm knife

The final step is slipping another #6 washer(s) on the end, then threading a 6/32 nut finger tight against the washer(s), an external lock washer and then tightening another coupling nut to serve as a 'knob'. Prevent the 6/32 nut from turning as you tighten the coupling nut and lockwasher to it.

I have not yet affixed a scale to the bottom of the jig, but it will certainly accomodate one. At the moment I am just scoring a line after a successful test cut.

This last image here shows the 'Mark I'. It is fabricated exactly the same way, but incorporates a threaded rod rather than a round headed bolt. I used double nutting to fix the end of the rod in place on the end nearest the bit which required more clearance. The effect of this requirement was that the Mark I will not adjust to as small a radius as the jig detailed above, however, it maxes out with a radius of almost 15"!. The Mark II, fabicated with a 4" 6/32 will max out at approximately 3.5" radius and a minimum of about 1.25" radius. Of course, if you can find a 6/32 stove bolt longer than 4" you can have a greater capacity