Some questions about template routing

[steve lewis]

Greeting to all from a 'newbie'.  I purchased a Kreg Jig back in October to make a painter's easel for my 4 year old grand-daughter--and when the garage warms up, I'll be able to get it finished.

Today's questions revolve (pardon the pun) around the use of a router to cut repetitive pieces using a template.  I see in the catalogs that there are guide bushings that fit to your router base plate and that there are router bits with top-mounted bearings to follow the template.  The question is: Do I use one method or the other, or are they somehow used in combination with each other?  My instinct tells me its the former, but I may not be properly visualizing the 'set-up'  if they are somehow used together.

The second question is about the bits with the top-mounted bearings.  The 1/4" shank styles are available in three different diameters: 1/2", 5/8" and 3/4".  It would seem to me that the speed at the cutting edge would be highest with the 3/4" bit.  Does this make it the most efficient for the job?

If it helps in what recommendations you would make, the parts being made are 'ribs' that must be exact in size, the router is a 1 3/4 hp, the material will be either 3/4" melamine or mdf -- rough cut to the basic shape to minimize the amount of material to be removed.

Thanks in advance for your thoughts.

[Robert J Guidry Sr]

You would use either the top mounted Bearings (flush trim bit) or the guide bushing, not both. When you use the flush trim bit, you would attach the template to your piece and set the bearing where the cutter is slightly above the work piece and into the template. When using the flush trim bit you make your template exactly the size and shape you want your piece to be.

When using the bushings, your piece will be larger than your template, you must remenber that their is a distance from the template to the cutter edge. you must determine the distance from the bit to the template and make your template accordingly. Keep in mind that you must always use the same size bushing and bit, if you change either you will change the size of your piece.


the flush trim bit is much easier to use for duplicating parts.

As far as the size of the bit, definately the larger the diameter of the bit the faster the bit will be moving, but a 1/2" bit is sufficient. I would also reccomend if possible use a 1/2" shank bit "if you can" and buy a quality bit.

[DAVID CZUPRYN]

Robert's advice is right on the money.You can take what he says to the bank.As to material,I'd use mdf,rather than melamine.Melamine tends to "chip out "along its top surface,unless using a down cut spiral bt.The bit can be a bit pricey. Dave Ps.If using dcsb,you'll need to use an appropriate bushing guide.

[Robert J Guidry Sr]

Did not think of it at the time, but if you are using a table mounted router, you should use a starter pin when starting your work. here is a link to help you if you do not have a starter pin for your table top router.
http://www.rockler.com/blog/index.cfm/2010/2/2/Back-to-Basics-mdash...

Robert J Guidry Sr said:

You would use either the top mounted Bearings (flush trim bit) or the guide bushing, not both. When you use the flush trim bit, you would attach the template to your piece and set the bearing where the cutter is slightly above the work piece and into the template. When using the flush trim bit you make your template exactly the size and shape you want your piece to be.

When using the bushings, your piece will be larger than your template, you must remenber that their is a distance from the template to the cutter edge. you must determine the distance from the bit to the template and make your template accordingly. Keep in mind that you must always use the same size bushing and bit, if you change either you will change the size of your piece.


the flush trim bit is much easier to use for duplicating parts.

As far as the size of the bit, definately the larger the diameter of the bit the faster the bit will be moving, but a 1/2" bit is sufficient. I would also reccomend if possible use a 1/2" shank bit "if you can" and buy a quality bit.

[joe vallender]

Size of the router bit will determine the speed that you can safely use that bit. You don't want the bit to fly apart. With a 3/4 size bit you are on the border of operating at 18000 rpm. The smaller bits can be operated safely at 20000 rpm. It is best to check with the bit manufacturer. [e-mail]