Newbie question about router table insert plates.

[Anonymous]

Hi folks, I'm new here. I've been reading this site for a while and it seems like a fun place.
I'm trying to get myself set up with some useful stuff to hopefully make some things from wood. A few years ago someone suggested I have a go with a router, so I did and enjoyed it (I still have the old Power Devil .) Two or three years ago I bought a Trend T5, which I like a lot, and now I want to sort out a router-table.
I have a fence (Jessem Mast-R-Fence) and a router table insert plate - a Rousseu one identical to the Trend one, but there's a couple of things I'm not sure about, and was hoping some of you nice people would know the answer.
The insert plate is Moulded with a slight crown for distortion free cuts. I'd have thought flat would be better, but there you go. My questions are these:
1: How does the crown aid distortion-free cuts?

2: When I route the rebate in the table, do I aim for the edges of the of the plate or the top of the crown to be flush to the top? Obviously if the edges are flush, the crown will be in the way of the fence, but wouldn't a flush crown cause problems with small pieces of wood?

Of course, these might be really dopey questions, but please be gentle, I'm new to this lark

Cheers!



Richard

 

[Noel]

Hi Richard, welcome to the site. The Rousseau plate (Trend et al only relabel it) is crowned to compensate for the weight of the router hanging from it. In theory this weight should make the plate flat and it seems to work in practice. Therefore when sinking the plate make the rebate a little deeper than the thickness of the plate and use levelling screws to bring the edges of the plate flush with the RT top.

Noel

 

[Anonymous]

Hi Richard, welcome to the site.

Ta muchly.

The Rousseau plate (Trend et al only relabel it) is crowned to compensate for the weight of the router hanging from it. In theory this weight should make the plate flat and it seems to work in practice. Therefore when sinking the plate make the rebate a little deeper than the thickness of the plate and use levelling screws to bring the edges of the plate flush with the RT top.
Noel

Ah, that makes sense.
I've made version 1 but it's not great, and may try for V2 before I get stuck in. Might as well get the table right before anything else.

Many thanks!



Richard

 

[Steve Maskery]

Hmmm...

I too have the same plate, and I'm less than ecstatic with it. It's true that the weight of the router will pull the tabletop down, and that the crown is SUPPOSED to compensate for it. It doesn't, at least, mine doesn't, and a 177E is not a light router. Mine is still crowned, and that causes me problems, though I admit it is mainly because I hve a mitre track running front to back for use with my horizontal mortiser setup. When using it in normal mode, lengths catch in the track sometimes.

I would be tempted to make my own out of steel or Al, with plastic laminate on the top. Of course the inserts themselves are more of a challenge, but it shouldn't be an insurmountable problem. I certainly wish I had a flat one that stayed flat all the time.

Any dissenters?
Cheers
Steve

 

[Argee]

Hi Richard, welcome to the site. The Rousseau plate (Trend et al only relabel it) is crowned to compensate for the weight of the router hanging from it.

NO, it's not! It's guaranteed NOT to sag. It has a crown in it in order to guarantee that the centre is the highest point.

The company's own specs (my emboldening) state:

# Fits All Routers
# Guaranteed Never To Sag!
# Life Time Warranty
# Exclusive Corner Snuggers TM
# Unique Leveling System

# Thermoset Phenolic Plate
# 9"x12" 3/8" Thick
# Fits Router Bits Up To 3 7/8"
# Small Opening Accepts Standard Template Guides
# Removable Rings Create 2 5/8" & 3 7/8" Openings
# Molded With Slight Crown For Distortion Free Cuts
# Removable Glass-Reinforced Polycarbonate Rings
# Insert Rings Snap Out For Various Openings
# Shoulder Pin For Starting Freehand Work
# Concentric Rings & Radial Lines For Centering Plate On Router
# Corner Snuggers TM Ensure A Tight Fit In Table Openings
# 1/4" & 1/2" Lip Permits Mounting In 3/4" Top

Aim to install the insert so that the edges are flush with, or just a hair below the table top. Bear in mind that the through hole is NOT the same size as the plate, but smaller in order for a rebate to be cut for the plate to sit on. The plate is held by four screws and small clamps, one at each corner. If you're laminating a top, remember to allow for this.

Ray.

 

[Steve Maskery]

Isn't the issue here whether or not this crowning does what it says on the tin? I say it doesn't.

I find it difficult to understand how, by having a workpiece that can wobble slightly over the hill, it improves the cut. And I strongly disagree that the plate can be a hair below the surface. Thw workpice will catch, or you will have to "wobble" it up onto the table surface.

I'm a bit surprised that there has't been more response to this, these insert plates are very common, Ray and I can't be the only ones to have tried them.

Cheers
Steve

 

[Ian Dalziel]

And I strongly disagree that the plate can be a hair below the surface. Thw workpice will catch, or you will have to "wobble" it up onto the table surface.

I dont have experiance with that particular plate Steve....Is it possible to drill and tap around the edges of your plate (where it sits on the shoulder)and insert grub screws to level it. When i cut my top out to accept the plate i cut it too deep by about a mm but i have leveling screws to take out any discrepencies.
I have also found liberons table wax used for machine tables to be a godsend on the router table.

Ian

 

[Neil]

Yep, I have the same gripe as Steve, although I've found that with the Makita 3612C (5.5kg) mounted the crowning seems to be pretty minimal. If I was buying an insert now, I would pay the extra £15 for the solid aluminium Jessem plate which seems very good value to me, and a lot less hassle than getting one made.

Neil

 

[Argee]

Isn't the issue here whether or not this crowning does what it says on the tin? I say it doesn't.

For me, the original "issue" was an oft-repeated but incorrect statement regarding the slight crown built into Rousseau inserts.

Having a totally flat insert that could sag would position the cutter fractionally above its intended depth (relative to the workpiece) and would not support the piece right at the point of cut. I cannot imagine a router heavy enough to cause significant distortion of that thickness of phenolic plate anyway - and I've got a really heavy router. However, I doubt that the Rousseau design was arrived at accidentally!

I find it difficult to understand how, by having a workpiece that can wobble slightly over the hill, it improves the cut. And I strongly disagree that the plate can be a hair below the surface. Thw workpice will catch, or you will have to "wobble" it up onto the table surface.

Let's remind ourselves that we're talking about a very slight, barely-discernible crown in the plate here, not a mound. Unless the workpiece is very short indeed, it will span from the table to the cutter and continue that line throughout the cut. The possibility of catching on the leading edge of the insert (the right-hand edge) is minimal, as the piece can be started by placing it on the insert prior to commencing the cut in the majority of cases.

However, if the piece needs to be started with the contact surface off the insert, then pushed through it, dead level or a hair below is the goal.

If the pressure (by hand or featherboard) remains on the right hand side of the cutter, then the workpiece will not foul the table on exiting the insert - at least, that's been my experience. If extreme pressure is applied to the leading edge of the workpiece once past the cutter it would be possible to catch the table - but why would such pressure need to be applied on the exit side?

I'm a bit surprised that there has't been more response to this, these insert plates are very common, Ray and I can't be the only ones to have tried them.

They are indeed common - I've got two, each mounted in flip-up tables and I love them. Aluminium flat plates are far more expensive and I've never felt the need to change to one.

Ray.