how to route small circles trend t3

[micks]

hi all i wish to produce a (washer) size 5 " outside, with a 4" central hole,

i have no trammel attatchment for t3 ,but in anycase the moter housing /base does not allow me to get a 2"rad.

so i need to make a jig for t3, have had a look for info ,but there are so many differant vertions, need something simple,

is it possible to cut circles using a router table i have small charnwood wo13 + router but cannot see how a circle could be cut on a table.

thanks all

 

[SketchUp Guru]

You could make a trammel from a scrap of ply or MDf and a small nail. Attach the scrap to the base of the router with flat head screws or even carpet tape. Plunge a small diameter straight bit through the scrap. Set the nail at the desired radius from the bit and cut it to make a small point.

Presto, trammel is done.

You could do essentially the same thing on the router table using a piece of ply or MDF large enough so it can be clamped down to the table. Raise the bit through the MDF and complete as above.

 

[Barry Burgess]

Mikes I tend to cut the outer edge 5" on the band saw and the inner using a drill bit. I have not got a very small router but if I did I would still use the bandsaw. I started out cutting larger circles with the router but the bandsaw is better of the outer circle. The problem with the router is if the board your are cutting is say 18mm then you have to do 2 or 3 cuts but only one with the bandsaw.
Barry

 

[CHJ]

micks,
These jigs give you any ideas?

 

[engineer one]

ok, silly thought whilst i agree with barry, the band saw is the best
for outside, but i wonder whether it might be possible to get
holes saws over 85 mm dia. or one of those horrible expanding drills
that go in a pillar drill.

you would need one for 128 mm for the outside, and then you could
remove if you could get a 102mm hole for the middle.

in principle you cannot cut within the centre of the base, because
you can't guarantee the support. any jig relies on the centre of the
hole being outside the base.

think laterally

paul :wink:

 

[micks]

thanks all like the jig as shown. what i forgot about was the adjustable circle cutting tools avaliable for the drill press .

i did manage to cut the (washer ) using a jigsaw , with workpiece clamped to workmate, but this was a bit akward,

it seems proffesional jigs state that they can produce small circles, but these would still be inside the router base,

thank you

 

[Roger]

These guys have some lovely Circle Jigs - and they work very well.

Jasper They are sold over here, but I just can't remember where I've seen them. I got mine over there!

 

[CHJ]

...snip..
in principle you cannot cut within the centre of the base, because
you can't guarantee the support. any jig relies on the centre of the
hole being outside the base. paul :wink:

Not so, look at the smallest radius in this picture:

Just need care on last 'breakthrough', cut, or fix the centre core area with double sided tape underneath

 

[Steve Maskery]

The jig you want is in Bill Hylton's book, Router Magic. It will cut circles any diameter down to almost zero (depending on how close to the end of the trammel you can realistically fix a pin without it coming out). I'll see if I can take a pic tomorrow.

 

[engineer one]

chas, happy to see that it can be done, just think it is easier
and quicker actually to use a different method


paul :wink:

 

[Lee Brubaker]

I have had the Jasper Model 400 for about 5 years & it does a very good job. The set-up is a little slow for each use unless you leave the jig on the router to serve as a sub-base. I use mine primarily for making hardwood wheels for wooden pull-toys. You get a nice clean cut without burning.

Lee

 

[micks]

hi all found this today re jasper jigs in the uk from wood workers workshop.

200 jig = £31.95

300 =£ 41.95

400= £21.95

including vat carriage £5

 

[Roger]

The 400 is incredibly easy and versatile to use. I've left it on a Porter Cable as a Base Plate so setup isn't an issue. The other one I used is the Lee Valley Universal Circle Jig - also made by Jasper but only for LV and has the disadvantage that the more varied circlers you route, the more holes you have to drill in it (although it would be easy to replicate it.

The later and more useful version of that one is the Jasper 300. They make a great combination.

 

[SketchUp Guru]

You could make a trammel for the application faster than you can lay your hands on a store bought one. And I'd guess you have the materials on hand to do it. Here's a drawing that ought to be self explanatory.

Stick the work down to a scrap of plywood with double faced carpet tape. drill pilot holes for the pin--one for each washer you need. insert the center pin in one of the holes in the base, plunge the router and make the cut. Multiple passes depending on thickness of the material. Move the pin to the other hole and repeat the process.

I'd be inclined to leave the thinnest sliver of wood and not cut through. A sharp knife and a wee bit of sanpaper would take care of the flashing that would remain.

 

[Steve Maskery]

This is Bill Hylton's jig:

The jig is screwed to the router and the arm, which runs in a T-slot, is clamped with a knob. It works well, and I think I can improve it further