Router bits,bearings and complementary curves

Re: Router bits,bearings and complementary curves

Henry (Raleigh NC)

Tom

I suspect that there are several ways to do this. You need to specify the exact process in order for me (and others?) to be certain exactly what you mean and whether the rule of 3x bushing size is valid. Details please.

Henry

Re: Router bits,bearings and complementary curves

Tom Norton

The example I watched,Stumpy Nubs. It would be easier to view than for me to explain.

https://youtu.be/fZmIMmdCTYA

Re: Router bits,bearings and complementary curves

John in NM

Yes, that is one way of doing it if you have the bearings & correct adapters to mount them.

What Ellis suggested with the guide collars is somewhat easier if you have a set of those, same 3x I believe.

I see the process - thanks

The plot thickens .....

Mark Hennebury

Another way to consider.

I did a lot of template routing a few years back, its quite fascinating and well worth getting to know. Many different ways to achieve the same outcome.

complimentary routing means whatever way you choose to do it, you have to move the cutter from one side of the finish line to the other.

This way consists of using a 1" flush cut bit and a 1/2" flush cut bit to make your jigs, then you can use any flush cut bit to make your finish pieces.



You screw a i/4" masonite template sheet to a spoilboard such as 3/4" MDF

Then you make your first template 1/2" offset from your finish

line.

screw that to your template boards.

Using a 1" flushcut bit against template #1 you cut a pass through the template board and make two template A&B

Your finish line is directly in the middle of these two templates.

Now screw on template B and make a cut with the 1/2" flushcut bit.



Then repeat on another sheet with template A

Once you have these perfectly fitted they can be your permanent templates. and you only need to use any flush cut router bit to cut your finished wood to size.

some credit card cases that i used to make.

makes sense...eventually

Bill Tindall, E.Tn.

I didn't understand the theory at first; then the light brightened.

"Your finish line[joint] is directly in the middle of these two templates. "

This approach depends on the fact that the center of the 1" bit traces the line that will be the joint between the two mating pieces. The edge of each template is 1/2" from this line. Hence, the outside arc(tip of cutter) of a 1/2" bit will trace this line if the inside arc (bearing) rides the template. neat. Don't know where I might use this pearl but I will file it away.

Re: The plot thickens .....

Tom Norton

Mark,though I am trying to do it with bushings not bearings I do have a question. In your explanation could a3/8" & a 3/4" bits be used??

Re: The plot thickens .....

Mark Hennebury

Tom, its the principle not the actual bearing size that counts.

Bearings may be a little more accurate than bushings, but either will work.

The size is not so important the relationship is.

You have to move the router bit above the joint line for the bottom piece and below the line for the top piece.

In the sketch;

The middle curve is the your joint line.

the lower curve is your template.

The top curve is irrelevant with using one template as in this example.

The small circle is a 1:1 ratio bit to bearing /bushing cut, cuts the top piece on the centre line.

The large circle is the 3:1 bearing/ bushing setup, the bit cuts the bottom piece of your pattern.

If your setup moves the router bit position like this they will fit.

Re: The plot thickens .....

Tom Norton

Mark, thanks I will have some time in the shop tomorrow and will try it out.

Without bushings, bearings or templates

Mark Hennebury

You can rout simple arcs or full circles with a simple pivot. by moving the point-routerbit centerline, equal to the routerbit diameter. So you use a pivot base on your router with two pin holes spaced apart 1/2" if you are using a 1/2" bit. Use one pin hole in your piece of wood on the bench that holds the piece you are cutting. Make one cut in your wood. remove and replace with the second piece of wood, change the pin to the second hole in your router base and rout your second piece of wood. your done.

Bingo!!!

Tom Norton

Mark,

I did a test this morning using a 3/4" bit and a 3/8" bit. I worked! I had a few "rough spots but I believe it was the fact I used some 1/4" ply to make the templates. Will do another test using MDF.

Thanks again!!

Re: Bingo!!!

Mark Hennebury

Great! Tom, just keep playing round and you will see that there are many ways and combinations to use when template routing, a lot will depend on what you have available in your shop, or can make or buy. Usually you can figure out some combination to make things work. Sometimes you may have to make a template to make a template to make a template, just to be able to use what bits and bearings/ bushings you have available. If you are going to do repetitive work, then you can get the correct bits, bearing, bushings and make proper jigs that, that are straight 1:1 ratio and done with flushcut bit/ bearings, no fuss, no figuring things out or dealing with offsets.

Re: Bingo!!!

Barry Irby

Mark's idea is a good one, but will only produce pieces that are a simple arch and a segment of a circle. I like it and will keep it in mind, but it will not work for a "wavy" curve. OTOH, it may make it clear in your head what has to happen for the pieces to fit as you want them. Part of it is keeping it clear that you have to move the bit by exactly a diameter.

Thus a 1/4" bit and a 1/2" bushing and a 1" bushing. The difference is that larger bushing moves the bit one diameter in all directions, if that makes sense.

Re: Bingo!!!

Tom Norton

The sample I did was a wavy curve and it worked. So I am not sure what you are referring to.