Why 51/64 Router Bushing?

[phrog]

I just received a set of router bushings for Christmas. Included is both a 3/4 inch and 51/64 inch bushing. I'm not sure I understand why two bushings so close together in size are included. Can someone enlighten me on this? Thanks.
Richard

[JR]

Just guessing, but it would probably be used when creating a dado for 3/4" plywood.

[LCHIEN]

couldn't find a ref or what its used for, I'll hav to think about hat for a while. But lots of sets include that size, so its a common use.

That's 3/64th over 3/4"

I assume OD.

[phrog]

Just guessing, but it would probably be used when creating a dado for 3/4" plywood.

I'm not sure I understand the concept here. What difference would the 3/64 make?
Thanks.
Richard

[phrog]

couldn't find a ref or what its used for, I'll hav to think about hat for a while. But lots of sets include that size, so its a common use.

That's 3/64th over 3/4"

I assume OD.

Yes, Loring, it's OD. I have also noticed that most sets include that size, so I thought someone on this site would surely have used it. Thanks.
Richard

[herb fellows]

By any chance, does it come out to be a metric equivalent?

[RAFlorida]

About 20.24 mm

Or rounded up to 20 and a quarter mm.

[JR]

I made a fancy schmancy diagram to prove my point. It disproved my point.

Go to the alternative theories from people who have a clue.

JR

[LCHIEN]

I found it.
Aparently popular hinge mortising kits work with standard 3.5" door hinges and 1/2" straight bits when used with the 51/64th OD, 5/8" ID router guide bushings.
Here's a couple, apparently there are more.

Milwaukee 49 54 0735 Hinge Butt Routing Template Guide Assembly

Precision-machined steel construction for accuracy and durability Universal, lock-nut design fits Milwaukee and most popular routers 5/8 in. inner diameter, 51/64 in. outer diameter, 9/16 in. barrel length Includes one lock-nut Limited warranty, Manufactu More
$6.75
from 1 store



Porter Cable Hinge Butt Routing Template Guide 42042

Hinge Butt Routing Template Guide Specifications Purpose Hinge Butt Routing ID 5/8 in OD 51/64 in Distance Pase Base 9/16 in-Tools/Power Tools/Routers/Accessories More

[phrog]

Thanks Loring. I had given up finding it myself. Makes sense.
Richard