Adding larger pilot bearing to existing 1/4" flush trim router bit

3084 Views 19 Replies 5 Participants Last post by bfblack, Oct 14, 2021

bfblack

Discussion Starter · Oct 11, 2021

I would like to add a 1/2" diameter pilot bearing to an existing 1/4" diameter Whiteside flush trim router bit RFT2100. Assuming I can find an acceptable 1/2" outside diameter bearing with an inside diameter of 1/4", any advice on how to attach the "new" bearing to the "old" bearing? The Whiteside bit is shown in the included photo. What looks like a nut on the tip of
the bit is NOT; it is permanently attached. Thanks in advance.
.

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John Smith_

· #2 · Oct 11, 2021

the way you describe it, you don't actually have this bit in your possession yet ?
what holds the 1/4" bearing to the end of the bit ?
(an actual photo of that part may help).

bfblack

Discussion Starter · #3 · Oct 11, 2021

I do have the Whiteside FRT2100 bit in hand. At the top of the photo is a forced fit sleeve (< 1/4" diameter) that keeps the 1/4" OD bearing in place. The actual bearing is just beneath the retaining sleeve.

I also have in hand a Lee Valley 1/4" flush trim bit (16J0904) with a removable 1/4" OD, 1/8" ID pilot bearing. I suspect finding a replacement bearing that gives me the desired OD of 1/2" will be even more difficult given that the ID would have to be 1/8".

John Smith_

· #4 · Oct 11, 2021

could you share your project with us that describes why the larger bearing is needed ?
depending on your project, I would try to figure out a different bit with changeable bearings.
are you limited to the 1/4" shank ?

since I have really scaled down my routering projects, I have started using Yonico bits exclusively.
they have a vast assortment of bearings that fit just about every application imaginable.

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bfblack

Discussion Starter · #5 · Oct 11, 2021

Thanks for the suggestion of Yonico bits. I am not familiar with this brand but will check them out.
The project is two route complimentary curves on the edge of two boards and have them mate near perfectly. I know how to do this using various combinations of guide bushings and/or pilot bearings. A colleague says he can do this with a single 1/4" diameter bit with a 1/2" diameter pilot bearing. Since I want to confirm his recommendation, I am not looking for alternative techniques but want to know how to get a 1/2" diameter pilot bearing on a 1/4" router bit. An example of this kind of joinery technique is shown below.

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John Smith_

· #6 · Oct 11, 2021

if you have a colleague that is already doing this, I would ask him for the advice since he has a proven method.
just to clarify the design you need, is this it ? or do you need the bearing on the top end.

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bfblack

Discussion Starter · #7 · Oct 12, 2021

Yes, the picture you posted is exactly what I am looking for.
The reason for posting the question on this forum is to see if other people have been faced with this problem and how did they solve it.

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papasombre

· #8 · Oct 12, 2021

John Smith_ said:
if you have a colleague that is already doing this, I would ask him for the advice since he has a proven method.
just to clarify the design you need, is this it ? or do you need the bearing on the top end.
View attachment 399809

I am curious about the way this router bit would work.

John Smith_

· #9 · Oct 12, 2021

me too, Papa - I'm curious about the whole project. without seeing photos of the jig and how the board is cut, it makes it hard to imagine how the pieces mate. all my pattern bits have top bearings, none have bottom bearings. (I like to see what's going on with the bearings).

according to the photo that Mr. Black posted; if I were to make that board, I would do the rough cut on the bandsaw and clamp both pieces near the jig edge and when you follow the jig with the bearing, both sides will mirror each other for a tight fit.
in my uneducated opinion, the size of the bit and bearing has no effect on the final cut of the two pieces. making the rough cut on the bandsaw will also have the effect of very little material is removed from both pieces to make them fit.
another way would be to make a template jig and use the 1/2" top bearing pattern bit that leaves a smoother cut.
as with any procedure, there is more than one way of achieving the same result = this would be mine.
I am going to try this method later this morning to see how it works.

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bfblack

Discussion Starter · #10 · Oct 12, 2021

So far, there seems to be more interest in Curved Joinery techniques in general instead of my original question about adding a 1/2" OD pilot bearing to an existing 1/4" OD flush trim bit. Attached is a pdf file that contains a collection of resources related to curved joinery; one can use guide bushings, top bearing bits and/or bottom bearing bits to accomplish the same result. Hopefully there is someone on Router Forums that has added a larger pilot bearing to an existing flush trim bit.

John Smith_

· #11 · Oct 12, 2021

yes, I'm sorry for getting off track.
my feeble brain couldn't digest the "reasoning" of the larger bit.
thanks for the PDF - it clears it up for me.

tomp913

· #12 · Oct 13, 2021

I don't see one with a 1/4" overhang - I have one that cuts a 3/16" overhang, used to trim laminate to the rough shape/size of the substrate before gluing in place but it's a 1/4" shank (and larger cutting diameter) which I don't see. Haven't seen it in a while but sure it's in the shop somewhere, and probably an Amana bit like these shown. Does it have to be 1/4" cutting diameter? Maybe you could take a standard trimmer bit (1/2" diameter and shrink/Loctite a sleeve on the OD of the bearing if you can't find a bearing of the correct size. Overhang Trim Bit Do a search under "Router Overhang Trim Bit", and look at those that show the bearing retained by a capscrew - you may be able to findd a bearing with the same ID but larger OD.

bfblack

Discussion Starter · #13 · Oct 13, 2021

tomp913 said:
I don't see one with a 1/4" overhang - I have one that cuts a 3/16" overhang, used to trim laminate to the rough shape/size of the substrate before gluing in place but it's a 1/4" shank (and larger cutting diameter) which I don't see. Haven't seen it in a while but sure it's in the shop somewhere, and probably an Amana bit like these shown. Does it have to be 1/4" cutting diameter? Maybe you could take a standard trimmer bit (1/2" diameter and shrink/Loctite a sleeve on the OD of the bearing if you can't find a bearing of the correct size. Overhang Trim Bit Do a search under "Router Overhang Trim Bit", and look at those that show the bearing retained by a capscrew - you may be able to findd a bearing with the same ID but larger OD.

If I understand the information on the link you provided, the Amana 47189 is exactly what I am looking for. I had never heard the term "overhang" bit. The woodworking literature I am familiar with always used the term "offset" but it is identical to "overhang". If this works out, I owe you big time.

tomp913

· #14 · Oct 13, 2021

I used the bit for rough cutting plastic laminate (Formica) to size, typically on L-shaped countertops where you couldn't just rip a sheet to size - the way it worked, you would set the larger piece on top of the countertop with an overhang on the back and one end and then trim around the open end of the L to give you some leeway when gluing down the laminate.. The original one was sold to me by the laminate distributor that I bought from as an "overhang trim bit", and that's what I've always called them. Glad I could help.

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PhilBa

· #15 · Oct 14, 2021

I don't quite understand why you need the overhang bit. Care to enlighten? I've done something quite similar using a plain-jane trim bit with lower bearing or maybe a pattern bit, I disremember. Details are searchable in the forum maybe around 2016ish (ie, me B2 lazee 2 look).

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tomp913

· #16 · Oct 14, 2021

When applying plastic laminate to a countertop, you will typically cut the laminate a little oversize so that you have an overhang to trim flush - the overhang gives you a little wiggle room so that you wind up with enough material to trim. If you're making a rectangular part, no problem as you just rip a piece out of a larger sheet. If the countertop has an L-shape, you can still rip a piece of laminate to the basic overall size, but it's a little unwieldy. So, you rough trim the larger piece closer to the finished size by laying it - with no contact cement applied at this point - on top of the counter top, with a little overhang on the back and end. Then use the bit to run around the inside of the L, effectively giving you an overhang around all edges of the top - this gives you enough material to trim to finished size. A search on YouTube will probably come up with somebody demonstrating this technique.

PhilBa

· #17 · Oct 14, 2021

PhilBa said:
I don't quite understand why you need the overhang bit. Care to enlighten? I've done something quite similar using a plain-jane trim bit with lower bearing or maybe a pattern bit, I disremember. Details are searchable in the forum maybe around 2016ish (ie, me B2 lazee 2 look).
View attachment 399823

OK, it's coming back to me. Used a pattern bit to cut a 3/8" dado that followed a template. Band saw to cut down the middle of the dado. Trim bit with lower bearing to clean up the edge of each side and then glued/clamped together with the thin strips in between.

bfblack

Discussion Starter · #18 · Oct 14, 2021

PhilBa said:
I don't quite understand why you need the overhang bit. Care to enlighten? I've done something quite similar using a plain-jane trim bit with lower bearing or maybe a pattern bit, I disremember. Details are searchable in the forum maybe around 2016ish (ie, me B2 lazee 2 look).
View attachment 399823

Very nice work, I am impressed. As far as "why you need the overhang bit", there is more than one way to skin this cat. As long as you preserve some things like offset (or overhang), you can achieve similar results with many techniques/tools. A colleague claimed that you could accomplish this task with a single router bit with 1/2" pilot bearing mounted on the bottom of a 1/4" OD cutter. I wanted to explore his technique.
Relative to your "disremember" comment, I advocate that the best way to do a particular task is the one that you can remember. I am definitely at this stage in life.

bfblack

Discussion Starter · #19 · Oct 14, 2021

2

tomp913 said:
I don't see one with a 1/4" overhang - I have one that cuts a 3/16" overhang, used to trim laminate to the rough shape/size of the substrate before gluing in place but it's a 1/4" shank (and larger cutting diameter) which I don't see. Haven't seen it in a while but sure it's in the shop somewhere, and probably an Amana bit like these shown. Does it have to be 1/4" cutting diameter? Maybe you could take a standard trimmer bit (1/2" diameter and shrink/Loctite a sleeve on the OD of the bearing if you can't find a bearing of the correct size. Overhang Trim Bit Do a search under "Router Overhang Trim Bit", and look at those that show the bearing retained by a capscrew - you may be able to findd a bearing with the same ID but larger OD.

While waiting on my Amana overhang bit #47189 to arrive, I was able to cobble together a bit that worked. I purchased a Whiteside ¼” OD (1/4” shank) flush trim bit (# RFT2100) plus pilot bearings (1/2” OD, ¼” ID from Wolfride via Amazon). The tolerances of the Whiteside bit and pilot bearing was such that I could force fit the big bearing onto the bearing. A 9/32” socket and small hammer was used to gently mate the two bearings. I make no claims that this cobbled together bit will last my lifetime or yours. I went through the steps my colleague suggested and it works. All work was done on a router table as it has good dust collection and does not require a spoiler board.

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bfblack

Discussion Starter · #20 · Oct 14, 2021

PhilBa said:
OK, it's coming back to me. Used a pattern bit to cut a 3/8" dado that followed a template. Band saw to cut down the middle of the dado. Trim bit with lower bearing to clean up the edge of each side and then glued/clamped together with the thin strips in between.

Phil: I found 81 posts started by you on Router Forums and browsed the titles. None seem to match anything related to curved joinery routing. Can you give me some more hints?

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