Small diameter circles.

Neanderthal

· #2 · Jun 4, 2005

I would make a sub base and lay out the radius of the small circle and drill the pivot hole in the base.
a blind hole in the base and the work. a short dowel pin for the pivot. i hope you get what i am saying.

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Neanderthal

· #3 · Jun 4, 2005

snowshoe Eagle-america has a small jig for 1" to 7 1/2" circles for 26$ hope this helps
http://www.eagle-america.com/html/catalog/productGroup.asp?id=332808

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reible

· #4 · Jun 4, 2005

Snowshoe said:
Does anyone have a home-made jig for cutting small diameter circles? (Smaller than the diameter of the base itself).

I have a couple trammels built from ShopNotes plans, but none of them have provisions for very small circles.

Thanks.

I have plans for a really cool one..... Since it is out of a book I can not post the plans here.

It will cut down to as small as 1" and as large as 7" (or more if you want). It is a sub base made out of plastic with a slot for the bit (1/4"+) and slots for two mounting screws to attach it to the router. You can set the dia of the cut to anywhere in the range. You do need to put a "pin" in the workpiece for the center..... Since you are all sharp people anyone here that wants to make one take a look at the sketch and figure out your sizes and enjoy. The view is from the bottom, the hole is for the "pin", the two matching slots are for the mount screws (flat heads). This of course may not work on your router..... and yes it is for a plunge router.

Ed

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NewMontanaWorkshop

Discussion Starter · #5 · Jun 4, 2005

reible said:
... segment deleted....

take a look at the sketch and figure out your sizes and enjoy. The view is from the bottom, the hole is for the "pin", the two matching slots are for the mount screws (flat heads). This of course may not work on your router..... and yes it is for a plunge router.

Ed

Most excellent! This was just the piece of info I needed, I have a few pieces of HDPE left over from making my router table -- one of those will work perfect for this jig.

Thanks again.

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template tom

· #6 · Jun 5, 2005 (Edited)

reible said:
I have plans for a really cool one..... Since it is out of a book I can not post the plans here.

It will cut down to as small as 1" and as large as 7" (or more if you want). It is a sub base made out of plastic with a slot for the bit (1/4"+) and slots for two mounting screws to attach it to the router. You can set the dia of the cut to anywhere in the range. You do need to put a "pin" in the workpiece for the center..... Since you are all sharp people anyone here that wants to make one take a look at the sketch and figure out your sizes and enjoy. The view is from the bottom, the hole is for the "pin", the two matching slots are for the mount screws (flat heads). This of course may not work on your router..... and yes it is for a plunge router.

Ed

A very popular circle cutting jig posted by Ed for routing small circles The only problem is adjusting to the various diameters required each time it is used. To adjust to size you will require to undo the four screws that hold it to the base. I have enclosed my circle cutting jig that can be adjusted from the top with the two screws that is used to hold the side fence attachment.( This is the side fence attachment for Makita 3612 or the Hitachi 12v) This certainly is easier to adjust. I use it all the time to rout circles from 30-40mm in diameter depending on the cutter used. It is also adjustable to increase the size of the circle simply by repositioning the "Pin"
I have also produced another jig that does NOT require the side fence attachment as illustrated.
Tom

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reible

· #7 · Jun 5, 2005

OH I see I said "flat head" I ment "pan head"..... sorry about that

Ed

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NewMontanaWorkshop

Discussion Starter · #8 · Jun 5, 2005

template tom said:
.... {segment deleted....
I have enclosed my circle cutting jig that can be adjusted from the top with the two screws that is used to hold the side fence attachment.( This is the side fence attachment for Makita 3612 or the Hitachi 12v) This certainly is easier to adjust. I use it all the time to rout circles from 30-40mm in diameter depending on the cutter used. It is also adjustable to increase the size of the circle simply by repositioning the "Pin"
I have also produced another jig that does NOT require the side fence attachment as illustrated.
Tom

Tom,
I have an M12V so that looks like a pretty handy solution also.

Thanks much.

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Julie

· #9 · Jul 11, 2005

Hi Tom
I'm a little behind on reading the posts, but curious about this jig of yours. Could you please explain it a bit more, I can't quite figure out how to use it. I do have the Hitachi M12V and would like to make small circles. Also what bit do you use? Thanks!
~Julie~

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template tom

· #10 · Jul 12, 2005 (Edited)

Julie said:
Hi Tom
I'm a little behind on reading the posts, but curious about this jig of yours. Could you please explain it a bit more, I can't quite figure out how to use it. I do have the Hitachi M12V and would like to make small circles. Also what bit do you use? Thanks!
~Julie~

Hi Julie
The side fence attachment was used for the original Circle cutting Jig This was secured to the base board 300mm x 160mm on the underside is inserted the fulcrum pin into 'Tee' nuts There are four nuts where the fulcrum pin can be re-positioned to give a great variety of circles. This has worked very well for me over the past 20 years
Tom

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RDMELLO

· #11 · Oct 15, 2006

Jr. Member. Since I'm Making The Circle Cut Outs On Top Of A Finished Desk, I Cant Put A Pivot Pin In The Top? If I Clamp Down A Piece Of Plywood And Use That For My Pivot, Then I Need A Long Bit To Cut Through The Three Quarter Inch Plywoo Top?

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bobj3

· #12 · Oct 15, 2006 (Edited)

Hi Rdmello
Because it's a Finished desktop I would not use anthing that needs to spin (turn) on the desktop I would use a brass guide with a plunge router and a 3/8" or 1/2" solid carb. bit.
Make a template out of 1/4" plywood with the right hole size (with a Forrester bit or scroll saw) you want to put in.
Then clamp it to the desktop with card board under the template then just plunge and cut out the small hole (Circle) you need.

Jasper hole jig below, from 1" hole to 18" quick and easy.
http://www.routerforums.com/jigs-fixtures/3584-jasper-circle-jigs-router.html#post35262

Bj

Just a Note*** I see that Tom recommend using straight cutter keep in mind that straight cutters are not made to plunge in, they will work but you will need to make very small cuts (shallow cuts)

Unless you have straight cutter that is made to plunge in, that's a bit with carb.tip on the top of the bit.
see link below.
http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_plung.html

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template tom

· #13 · Oct 15, 2006

RDMELLO
You will require to make a Template then very carefully rout out the circle with a straight cutter
Tom

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gimpy

· #14 · Oct 19, 2006

Shopnotes magazine issue #83 has an article on building a small diameter circle jig (1/2 inch to 4 inch circles). Seems to be pretty elaborate, using a lazy susan in the jig. Issue 83 is from October/November, 2005. (begins on page 32)

Frank

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mpphoto

· #15 · Oct 19, 2006

I just put half-circles on the back edge of two desktops so I could pass power cords through them. I used a hole saw to cut a 2.5" diameter hole in a piece of 1/2" mdf. Then I clamped the mdf to the desktops and used a template bit to rout out the hole. Very nice, neat job. At some point I intend to make an mdf template with an assortment of circle sizes for future use.

Michael

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sawstop

· #16 · Nov 7, 2006 (Edited)

Circle Jig

NewMontanaWorkshop said:
Does anyone have a home-made jig for cutting small diameter circles? (Smaller than the diameter of the base itself).

I have a couple trammels built from ShopNotes plans, but none of them have provisions for very small circles.

Thanks.

This may not be what your looking for but it is capable of cutting diameters from 1" to 7-1/2" in 1/16" increments and is calibrated for use with a 1/4" straight bit.

Precision Circle Jig
http://www.leevalley.com/wood/page.aspx?c=1&p=40970&cat=1,43000,43001

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Rosemary LYNDALL WEMM

· #17 · Nov 23, 2006

Other solutions

For very small circles

1. use a hole saw on a drill press rather than the router.

Or

2. use a template with a very long handle and a backing of doublesided tape together with a flush cutting bit and a sacrificial backer board beneath your work piece.

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Hamlin

· #18 · Nov 25, 2006

Perhaps I've misread the entire question but, if all you are doing is cutting "holes" smaller than 1", a drill & bit/hole-saw is the only way to go. If you are making circles such as small "wheels" then a jig is needed.

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Mike

· #19 · Nov 25, 2006

One of the handiest tools for making small circles is a RotoZip or similar product. The circle cutting jigs work well. Just be sure to use a "Sabercut bit" designed for cutting wood. These bits will also work in trim routers, so if yours has a circle jig you have another possibility. Spiral cutting bits make clean cuts so dont rule out these small machines.
Another thought would be to build a simple jig for making different sized small holes. A 1/4" thick piece of Plexiglas or Masonite(hardboard) 6" wide by 3 or 4' long. Drill different sized holes using Forstner bits, hole saws or even adjustable hole saws along the centerline. The 6" width will provide good support for your router, the length will allow easy clamping. By using a combination of pattern following bits and guide bushings you can figure on making at least 5 or 6 variations on each hole size. To keep life simple I suggest using a 1/4" plunge bit and figuring your hole sizes from this. If you are likely to build projects with many different sized small holes this is the way to go.

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