Flush Trim Router Bit

[Tobykanobe]

I have a plywood counter that is two 3/4" ply, sandwiched together with glue and screws.  The edges need to be trimmed before I add the hardwood edges.  I'm not very familiar with router bit terms and just want to make sure I order the correct flush trim bit before I click buy.  If I want the bearing to roll across my reference edge, with the cutter below cutting the over-sized edge down, I would want that bearing to be at the top of the bit, not the bottom right?  It seems the basic models of flush trim bits have the bearing at the bottom.  Can you help me choose the  correct one for what I've described?

[JohnG]

Also look at ‘template’ or ‘pattern’ bits. You’ll probably want 1” cutting length, shank size will depend on your router. 

[Chestnut]

2 hours ago, Tobykanobe said:

I have a plywood counter that is two 3/4" ply, sandwiched together with glue and screws.  The edges need to be trimmed before I add the hardwood edges.  I'm not very familiar with router bit terms and just want to make sure I order the correct flush trim bit before I click buy.  If I want the bearing to roll across my reference edge, with the cutter below cutting the over-sized edge down, I would want that bearing to be at the top of the bit, not the bottom right?  It seems the basic models of flush trim bits have the bearing at the bottom.  Can you help me choose the  correct one for what I've described?

So this is top bearing
https://www.amazon.com/Freud-Bearing-Flush-Shank-50-118/dp/B002IPHGAW/ref=sr_1_3?keywords=freud+42-204&qid=1575133439&sr=8-3

And this is bottom bearing.

https://www.amazon.com/Freud-Downshear-Helix-Flush-42-204/dp/B000BV9IPG/ref=sr_1_1?keywords=freud+42-204&qid=1575133439&sr=8-1

And this is the one i'd get

https://www.amazon.com/gp/product/B0032YX634/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I have all 3 of those and the whiteside is a great bit and has 1_1/2" cutting length which is what you need. With the white side as long as the surface you have to cut is 1_1/2" or under (which you will be good as plywood i sundersized) you have the flexability to use either top or bottom which is good flexability to have.

I always get confused which is top and bottom so yeah.

[JohnG]

I thought OP was flushing the bottom sheet of ply to the top one. If you are flushing both sheets then you will need 1.5” cutting length and not 1” like I previously mentioned. 
 

Whiteside bits are great.

[Chet]

These are a really nice bit, a little more money but they have a top and bottom bearing so they have more flexibility in how they can be used.  They are worth the money.  I purchased the 3/4 diameter with the 2 inch cutting length and just used it a lot in a recent project super clean cut.  I used it on both hardwood and ply.

https://www.infinitytools.com/routing/router-bits/carbide/flush-trim-router-bits/mega-flush-trim-router-bits

[Mick S]

11 minutes ago, Chet said:

These are a really nice bit, a little more money but they have a top and bottom bearing so they have more flexibility in how they can be used.  They are worth the money.  I purchased the 3/4 diameter with the 2 inch cutting length and just used it a lot in a recent project super clean cut.  I used it on both hardwood and ply.

https://www.infinitytools.com/routing/router-bits/carbide/flush-trim-router-bits/mega-flush-trim-router-bits

Agreed. Those are nice bits and should keep from chipping out the top or the bottom. A little more, but beefier bits. I have a couple of Whiteside pattern bits. Nice, but very $$!

[Tobykanobe]

Awesome. That's just what I needed.  Thanks all!

I settled for now for the Whiteside Router Bits 2715 Combination Flush Trim Bit with Top and Bottom Bearing.

I l like buying things in sets, but with xmas upon me, will have to settle for the cheaper option for now.

 

[sanderrz7]

There are a lot of details which can be the most important part of work. And my uncle knew that, when he made me a present of Freud 91-100 13-Piece bit set ( one of the sets over here: https://www.woodroutersreviews.com/best-router-bits/ ). That's what I needed, cause I'm a beginner and they are perfect for beginners and newbies. Which is even more important is that they come with a lifetime warranty from a producer.

[curlyoak]

On 11/30/2019 at 12:58 PM, Chet said:

hese are a really nice bit, a little more money but they have a top and bottom bearing so they have more flexibility in how they can be used.  They are worth the money.  I purchased the 3/4 diameter with the 2 inch cutting length and just used it a lot in a recent project super clean cut.  I used it on both hardwood and ply.

If you have a powerful router, how much of a bite in 1.5" thick oak can you take?  Can you take a bigger bite with the larger diameter bit? Thanks.

[RichardA]

18 minutes ago, curlyoak said:

If you have a powerful router, how much of a bite in 1.5" thick oak can you take?  Can you take a bigger bite with the larger diameter bit? Thanks.

Why would you take that chance?  A hidden knot, can cause you more problems than you need.

[curlyoak]

It is not a question of taking chances. The question is how much of a bite can you take without compromising the work or the tools. Not  trimming beyond safe operation. I thought was assumed. So how much bite and which bit if either gives you a bigger bite? And what amount of wood on 1.5" oak do you trim?

[wtnhighlander]

The 'bite' is all about chip load. Vary the cut depth (bite) and feed rate to keep it somewhere between bogging down the motor (too much) and burning to wood (too little).

A late member here, called Particleboard, once provided a good deal of technical data for chip loading of routers and shapers. A search for postings by Don Whacker may turn up that data, and there are a few experienced CNC operators here that can probably shed light on the subject, too.