How do I use my "male" template to make a "female" piece

[Steven Wayne]

I have a 1/4" thick template that is a "rounded corner-ish rectangle". I want to make it's mate - an opening in a larger piece of sheet that this template would exactly fit in.

For the life of me, I can't figure out how to do this.

Photo of template:

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[Derek Stockley]

Here's how I'd do it:



Put the male template on either your part blank or a sheet to make your female template where you want to cut the opening.
Lay out strips of wood against the edges of the male template, lining up the end of the first strip with the top left corner of the male template, and going clockwise around the male template so that the end of each strip butts up against the long edge of the previous strip. The strips will sort of interlock in this arrangement so you don't have to cut any of those to length accurately.
Double stick tape or tack the strips down.
Pull out the male template, and the strips are your female template.
To establish the radius in the corners, use an appropriate sized drill, forstner bit, or if it's small enough, router bit with a guide bearing.
Rout along the straight edges with a guide bearing


If you need a reveal or slightly looser fit, put shims between the male template and the strips before sticking the strips down. You can use the strips either as your final template or to make your final template, depending how many openings you need.

[John Coloccia]

First, it would be easier if you had started from a female template. Then I could have pointed you to the Whiteside inlay kit. You make a slightly oversized female template, and the the kit works like magic.

Use a 1/4" flush cut bit and go around your template making a FEMALE pattern in another piece of wood. You must be extremely careful to not let the bit come off the template, of course. It's not easy. You also must be extremely careful to make sure that you've secured both the new template you're make and the offcut inner piece so that nothing moves after you've finished your cut. I use double sided tape on a sacrificial board underneath.

So now you have a female template that's 1/4" oversized. Go around that with a 1/2" bit and a 1" router bushing. That will reduce that template by 1/4", giving you a match.

This is a royal pain, BTW. What I do, especially when I need to make more than one of these, is use the Whiteside inlay kit to make template, and then make the parts from the templates.

edit: if your corner radius is less than 1/4" (because the initial 1/4" bit will increase it by 1/4", giving a 1/2" radius), then use a 1/4" bit with a 3/4" bushing for the last part.

[Peter Quinn]

Do you have a set of brass bushing guides for a router? You can get to the female with the right combination of bushings. First you screw or tape your male to a larger sheet of template material, you go around it with a plunge router with a smaller diameter bushing guide, say a 1/4" bit with a 1/2" OD bushing guide. This will make a female, then you change bushing guides, same bit, choose a larger bushing guide of appropriate OD that will off set the cutter back to the inside and match the outline of the original male template. It helps me to make a quick story stick to get the off sets and bushing sizes correct.

[Richard Dragin]

Peters answer is correct but to make it a little easier to understand....You need to make an intermediate template from the one you have before you can make your final piece.

[John Coloccia]

If you use a 1/4" bit with a 3/8" template (I don't think it will fit in a 5/16"), that will give you a female pattern that is 5/16" too large. That means you need a 3/8" bit with a 1" bushing to get a 5/16" offset to make the real template. Please check my math but I think it's right. Most people don't have a 3/8" bit laying around, and it's impractical to do this with a 1/8" bit. That's why I suggest a 1/4" flush cut and a 1/2" bit/1" bushing (or 1/4" bit, 3/4" bushing) because it's what most people have laying around. The all bushing route is theoretically sound but not very practical IMHO.

I don't know of any other common combination that will work, but if someone knows of one I'd love to know about it. I've thought about it for a bit and this is all I could come up with when I had to do this for myself not too long ago.

[Brian Kerley]

If you use a 1/4" bit with a 3/8" template (I don't think it will fit in a 5/16"), that will give you a female pattern that is 5/16" too large. That means you need a 3/8" bit with a 1" bushing to get a 5/16" offset to make the real template. Please check my math but I think it's right. Most people don't have a 3/8" bit laying around, and it's impractical to do this with a 1/8" bit. That's why I suggest a 1/4" flush cut and a 1/2" bit/1" bushing (or 1/4" bit, 3/4" bushing) because it's what most people have laying around. The all bushing route is theoretically sound but not very practical IMHO.

I don't know of any other common combination that will work, but if someone knows of one I'd love to know about it. I've thought about it for a bit and this is all I could come up with when I had to do this for myself not too long ago.


Well, the equation is:

d_bushing2 = 2 * [(d_bushing1)/2 + (d_bit)/2]

That's assuming the bit remains constant.

In this context, a 1/4" bit, with a 1/2" bushing, would end up requiring a 1" bushing with the same 1/4" bit.

[John Coloccia]

Excellent, Brian. That's about the only common combination that works I think. I don't know why I missed it.

[Richard Dragin]

Well, the equation is:

d_bushing2 = 2 * [(d_bushing1)/2 + (d_bit)/2]

That's assuming the bit remains constant.

In this context, a 1/4" bit, with a 1/2" bushing, would end up requiring a 1" bushing with the same 1/4" bit.

Am I correct in thinking that works as long as you don't have less than a 1/2" radius on the corners?

[John Coloccia]

1/4 with a 1/2" bushing gives a 3/8" offset to the outside of the cut, and ultimately you need to get a 1" bushing in there (1/2" radius), so an outside radius can actually be as small as 1/8" because the first cut enlarges everything by 3/8". I think that's right. Of course an inside radius needs to be larger than the bushing. Am I think about this correctly?

[Steven Wayne]

Thank you all for the replies! I ended up going with Derek's suggestion. I had some 3mm thick PVC foam board in the shop. So, I cut 5/16" wide strips of it, used thin cardboard around the border of my male template and stapled the PVC firmly to the edge all the way around - heating it to get it to conform to the corners. It worked well. Would have been easier if I would have had 6mm PVC board.

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End result:
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[Peter Quinn]

Most people don't have a 3/8" bit laying around

LOL, I guess as usual I fall into the category of "not most people', as it turns out I have a 3/8" spiral carbide with its own 3/8" collet to match, something I bough for a job that required it, haven't found much use for it since. It has literally just been laying around. But now I have another use for it! I guess the op has it conquered, but I'm guessing Brian's formula is correct, I know I've done this a handful of times in the past at work using a single bit and two different bushings, I usually have to feel my way through it with a story stick to figure the offsets. Why do contractors so often bring you a male template when you need a female to make the actual work?

[Myk Rian]

LOL, I guess as usual I fall into the category of "not most people',
I have several of them also. Not uncommon at all.