# how to trace a reduced template for bushing offsets



## archer33 (Apr 25, 2010)

I thought of a method for template making that shrinks a template tracing to adjust for the offset a bushing on your router creates. I read in a Rockler forum about a guy who uses washers to trace around shapes. Putting a pencil in the washer hole he rolls the washer around the shape to trace. This way the tracing will be slightly larger (the width of the washer metal) than the original. This gave me the concept for allowing for bushing offsets. By the way, paper is too thin for the washer to follow. Thick card, masonite or foam core would work. Corrugated cardboard is also problematic. Anything thicker than the washer thickness itself with a solid edge works.
Trace your object or template to size directly (without the washer) onto a sheet of foam core or thick card significantly larger for stability and cut out the shape carefully with an X-acto blade or Dremel tool. Set aside the shape you just cut out and then, using the washer, trace on the inside of the cutout. The washer must have the same metal width as the bushing offset you plan to use. This gives you a template drawing with the bushing offset built-in. 
If you cannot find a washer with the right width, a drill bit can enlarge the hole to reduce the metal width for the pencil to ride on. Make sense? 
Then cut out your hardboard template to the exact size of your new drawn pattern and it will be the right size (i.e. shrunk slightly) for your router bushing and will reproduce your original pattern or element to its original size. There is a small issue with the washer rounding off square edges slightly and not going into sharp detents or the meeting point of curves. Simply use a square or plastic triangle to sharpen any corners and hand draw to sharpen the areas meeting at the inside corners of intersecting curves. I hope this low tech method helps and cuts down on the extra router work and wood materials involved in other methods of adjusting tracings for bushings.


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## BigJimAK (Mar 13, 2009)

For anyone having a tough time visualizing what Stephen's talking about, here's a web site with pictures.

Veritas® Offset Wheel Gauges - Lee Valley Tools


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## harrysin (Jan 15, 2007)

Thanks for the post Stephen, but honestly, this is rather like teaching primary school children maths by using calculators, they'll be totally lost if their calculator breaks down in later life! It's far better to get a full understand of how to calculate off-sets. It's so simple, take the diameter of the guide, minus the diameter of the cutter then divide by two for the off-set. If one is serious about routing, then one should build up a good selection of cutters and template guides which will enable just about any project to be made accurately. I'm not suggesting that everyone builds up a collection to compete with Bj, but around twenty guides, a mixture of Imperial and metric would make for great versatility.


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## crquack (Oct 10, 2008)

steph33,

Thank you.

I had to read your post 5 times before I grasped the procedure but now I understand it it will be a great help to me in routing complex patterns. I was wondering how to transfer an outline of a shaggy dog to a template to get the original size! No amount of math will help with that.

I think I am correct in saying that the procedure to get the original size in negative (i.e. a hole) would be different in detail but similar in principle to getting a solid object as you describe, yes? You would use the part that you cut out (original size) and draw on the outside of it with the washer, cut out the new pattern and use the hole as the new template?


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## archer33 (Apr 25, 2010)

That's correct. Tracing inside the "hole" or negative with the washer reduces the original drawing by the width of the washer's outside to inside edge. This is why the washer must be the same width as the router bushing offset if the goal is to achieve the original size with a bushing surrounding the bit. Tracing the positive shape I said one should set aside (i.e. not use) will make your new tracing that same amount larger than the original shape. If you cut that out of a large sheet of MDF for instance,and routered the inside or negative with the same size bushing you'd end up at the same size as the original drawing. Two ways to arrive at the same destination.


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