Routing a circular rebate

[John G]

I need to make some circular rebates to flush fit some circular drawer pulls I am using.
I've thought about hole saws and forstner bits, but none are the required 55mm diameter.
So I think I need to use my router with a template guide (Tom O Donnell rejoice!)

Trouble is, to make an accurate circle, I need to make a template with another accurate circle. So I am back where I started! For example, to use a 10mm bit in a 30mm template guide, I will need a template with a 75mm circle.

So how do I make a template with an accurate 75mm hole?
Or can I buy a template from somewhere?
Or is there another way to cut my 55mm rebate?

I have read the previous topics discussing circle cutting jigs, but am not sure how accurate a home-made one would be. Also, for a 75mm hole, the centre would be somewhere under my base plate, so how do I fix my centre?

[q9]

Just a thought:

If you need a template but can't find one, then perhaps the local engineering shop could cut a 75mm hole in something suitable for a reasonable fee?

[Eastie]

How about those drawing stencils (stabilo i think). They are only thin plastic but they do come in all shapes and sizes and are relatively cheap. Most stationary suppliers stock them.

[mikmaz1]

hi john,
see if you can get your local library to get in a book called router magic by bill hylton.
he has a trammel jig that will cut holes from 25mm up to approx 400mm of course you have to make it first.
seeyasoon mik

[bobmundy]

John.
Have a CNC router and can cut your template if you wish. Let me know the thickness required, and exact size.
Email/fax or phone........

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Bob-
You'll never get a second chance to make a great first impression...

[Little Festo]

I had a look in the Timbecon Catalogue. They have listed a 2.125" forstner bit (53.975mm).

They also have listed a "expansive bit" 22 to 76mm.

Peter

[soundman]

A couple of thaughts
I would recomend the router with a template.

Dont be afraid to cut the template with a jig saw or a fret saw and tidy it up with sand paper to the marked line.

alternatively
get a mate with a lathe to cut you a hole.


personaly i have a downlight cutter which will cut a nice hole from about 20mm to about 180mm very handy used in the drill press.

there are other cheaper adjustable hole cutters FH prager do one.

cheers.
spinn it up mate!!!

[John G]

Thanks All,

I ended up making a circle cutting jig out of some hardboard. It was a little tricky figuring out where the hole centre should be, since it's measured from the outer edge of the cutter, and I needed a radius of 36.1mm.

However, it seems I fluked it first go, as my test circle was just what I needed!

The lesson though may be to invest in a proper circle cutting jig...

[Tom O Donnell]

Just logged into the site.Too late
The easy circle cutting jig is explained on my home page www.wa1.quik.com.au/tomodonn (http://www.wa1.quik.com.au/tomodonn)
Tom

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TomnJarrah

[Glen Bridger]

Hi

Cutting circle rebates is real easy if you can put up with a small nail hole in the centre. You need a thin piece of MDF slightly larger than the base of your router. Place the template follower on the router. Then mark the centre of the router spindle on the MDF then calculate the radius you will need and mark it on the MDF. Remember to substract half of the diameter of the cutter from the radius of the hole you will be cutting. With the centres marked, drill one hole to suit your template follower and the other will be 1.5mm. Place the MDF circle cutter on the job and locate the centre of your circle with a 1.5mm nail (cut the head off) and tap it in.
The router will rotate around the nail and cut a perfect circle every time.

Cheers,

Glen

[derekcohen]

John

Reading the earlier posts I think I see where your problem lies.

It appears that you conceptualise a circle template as a hole into which you run the router bit. For this reason you are looking for the perfect hole.

Well, that is one way to do it, but you depend on having a hole in the first place, which you lack.

The alternative is to use a form of trammel, which Tom (and many books) do describe. A 55mm hoile is going to require a very tight turning circle. Frankly, it is not my idea of fun. I would use an expandable (circle cutting) drill bit (which even Bunnies sell).

But if you must use the router, cut a 400 x 150 mm rectangle of MDF, attach your router (with a 1/4" straight bit) about a third the way down, plunge the bit through the MDF, then mark off a point 27.5mm from the outer edge of this hole and drive a nail through at that point. There you have it, a router jig to make 55mm holes.

Best of luck

Derek (in Perth)