If you can get your head round the metric system the answer is quite simple.
Rout the shape with a 30mm template guide and a 10mm cutter the rout the piece to be inserted with a 16mm template guide and a 4mm cutter.
I know there is a commercial brass set available with a template guide and a sleeve that fits over the guide using the one size cutter, I don't have it and I have always used the other system
Tom

 

You could also create the male piece first and then use it to create a template for the female part. Attach the male part to your template stock with double sided tape or temporary fasteners and then use a 7/16" guide bushing along with a 1/4" cutter to create the template. Then use the template along with the 1/4" cutter and a 15/16" guide bushing to route the recess to recieve the male part.

Lee Valley sells a 15/16" collar that attaches to a standard 7/16" guide bushing for about $6 and it works great for this purpose.

http://www.leevalley.com/wood/page.aspx?c=2&p=41779&cat=1,43000,51208

 

Thanks for the link

You could also create the male piece first and then use it to create a template for the female part. Attach the male part to your template stock with double sided tape or temporary fasteners and then use a 7/16" guide bushing along with a 1/4" cutter to create the template. Then use the template along with the 1/4" cutter and a 15/16" guide bushing to route the recess to recieve the male part.

Lee Valley sells a 15/16" collar that attaches to a standard 7/16" guide bushing for about $6 and it works great for this purpose.

QUOTE]

Thanks for the link, I had basically the same question, as i wanted to get away from the 1/8' bit and use a 1/4" with a collar on the bushing..

Tom

 

Hi Phil M

Here's some more help on inlays

Making an inlay with your router
http://www.routerworkshop.com/inlays112.html

Making An Inlay Template
http://www.routerworkshop.com/revinlay.html

Video ▼
http://www.woodworkingonline.com/?s=inlay

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Lee Valley tips ( How-To )

http://www.leevalley.com/shopping/Instructions.aspx?p=40701

http://www.leevalley.com/wood/page.aspx?c=2&p=41779&cat=1,43000,51208


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I can't get my head around creating two identical parts, one male and one female part that will fit perfectly together with only one template and a bushing set.

Can anyone give me a run through on how that's done, I'd like to know if I need to create a male or a female template for this and which bushings and size bits I should use. This is what I'm trying to make, it's about 6 inches long.

 

You guys are great! thanks for that. That video was very helpful.

To recap, the only bushings I have are a 10mm and a 17mm. So if I use a 3.5mm bit and a female template, I only need to make the female rout with the 17mm bushing and the male rout with the 10mm bushing right?

 

Phil

Great to see someone else using the metric system, yes and your answer is quite correct.
Tom

 

Another idea

I have another solution based on my intention to use 1/2" size bit for the actual cutting/routing

I would create the male part first (or the male part is a ready item such as a medal or coin)
Then use a 1/4" bit with a 5/16" bushing to create a template. (template material is thinner so 1/4" bit is used for accuracy)
Then I would use a 1/2" bit 26.8mm bushing to route the recess for the male part

27mm guide bushing is available from Trend, but I just made a ring out of MDF OD 26.8" internal diameter 3/4" and slip it over my 3/4" bushing.
method:
1. Draw 27mm circle on MDF
2. Cut an accurate 3/4" hole using 3/4" bit through MDF.
3. Used scroll-saw to roughly cut outer circle about
4. Mount on lathe and turn outer diameter to 26.8mm.
5. OD confirmed with digital calipers.
It is possible to just use a drill press if you do not have a lathe. Hot Glue a 3/4" drill bit to the rough MDF ring. Sand on a drill press until 26.8mm




calculations.
5/16" (7.8 mm) bushing with 1/4 bit (6.35mm) gives 3.9 + 3.17 = 7.05mm displacement to make template.
26.8mm bushing with ½” (12.7mm) bit gives 13.4 – 6.35 = 7.05 mm

Reuel

 

I don't understand your calculations, using a 7.8mm template guide with a 6.35 cutter, would give: 7.8 - 6.3 = 1.45 divided by 2 gives an offset of 0.725mm

I agree with your second calculation.

 

Hi Harry
I have edited the text as it was a bit misleading.

What I am trying to do is to use a ready male part to create a female template.
So the displacement is 1/2 *bushing OD size + 1.2* bit diameter.

The second calculations is when the female template is used to actually route the female recess. So displacement is 1/2*bushing OD - 1/2 * bit diameter.

Reuel

 

I've been reading this thread with great interest, partly because I'd like to try this and partly because the math as it's presented has me a bit puzzled. {5/16" = 3.94mm (not 3.8) and if the other calculations are rounded off in different directions there might be some gaps or sanding depending on which way the rounding goes?}

I'm sure this is a lot simpler than I understand it, but the way I see it is this:

The cut line for both female and male parts has to be in the same place to fit tightly so measuring from the same pattern edge,

Female :: guide bushing radius - router bit radius = cut line​

Male :: guide bushing radius + router bit radius = cut line​

So :: guide bushing radius (F) - router bit radius (F) = guide bushing radius (M) + router bit radius (M)​

Then the challenge is to find the smallest possible guides and bits combos that leaves the least amount of cleanup with a chisel on the female cut or corner sanding to round off the male cut?

I think I'll just go and try it.....

(just thinking out loud)

cheers

John

 

Had you mentioned making MDF rings I would have suggested this simple method, by which you can have a combination of any inside/outside diameter using the router with a suitable circle cutting jig. These shots are from an earlier answer that I gave to a members question. The last shot is a ring that I recently made and posted, for a doughnut chuck for my lathe.

The ring shown was 2.5" OD with a 0.75" hole, hence the plug arrangement, for holes within the capabilities of the jig, inside and outside can be routed with the jig, the one shown is infinitely adjustable from about 30mm to very big, and was made by me but designed by another member.

 

Thanks Harry

I already have circle cutting jigs small & large circles - as per RON FOX's idea.

But since the guide bush rings very small & thin only about 3.5 mm thick and need internal & eternal diameter precision to 0.1mm, I have made with my lathe.

For larger circles I will definitly cut with circle jigs or on my self made router table that I have made an adjustable pivot for circle cutting.

Reuel