rousseau crowning glory?

[johnnyb]

having just installed a rousseau router baseplate and placed a straight edge across the table and insert i see its crowned in a very specific way. the lead in edge in the middle is proud but the corners are flush, the area surrounding the inserts are proud but the inserts themselves are low and the lead out edge is perfectly flush all over. why is this better than a flat table? it is obviously designed this way, my triton certainly doesnt pull it flat. ps i heartily recommend ron foxes method of cutting the rebate(on the wealden site) using the perform 1/2 inch 3/4 deep template cutter is just about perfect with 18mm mdf i also cut the mitre track using this method simple and perfect.

 

[Paul Chapman]

I've read somewhere that some router table insert plates sag when the router is fitted, so some manufacturers deliberately make their inserts crowned to overcome this, the theory being that the weight of the router will pull it flat. Yours doesn't, so it seems that you have the same problem as a sagging insert but in reverse. Can't think of any reason why you would want a router table that isn't flat.

Cheers :wink:

Paul

 

[Steve Maskery]

Can't think of any reason why you would want a router table that isn't flat.

Absolutely. The are pain in the posterior. I have one and wish I'd chosen differently. I think we are already discussing this very issue in another thread somewhere, aren't we?

Cheers
Steve

 

[Argee]

I've read somewhere that some router table insert plates sag when the router is fitted, so some manufacturers deliberately make their inserts crowned to overcome this, the theory being that the weight of the router will pull it flat. Yours doesn't, so it seems that you have the same problem as a sagging insert but in reverse. Can't think of any reason why you would want a router table that isn't flat.

The very slight crowning is not there to counteract sag, it's deliberately designed to ensure that the part surrounding the bit is always the highest - just by a hair - so that the relationship of the bit to the surface doesn't vary. In use, I've never noticed it and it's not visible to the naked eye. Lee Valley also design their plates this way, I believe.

Ray.

 

[Paul Chapman]

I think we are already discussing this very issue in another thread somewhere, aren't we?

Yes https://www.ukworkshop.co.uk/forums/view ... hp?t=15033

Cheers :wink:

Paul

 

[Paul Chapman]

just by a hair

From the way Steve has described his, I had assumed it was more than just a hair.

Cheers :wink:

Paul

 

[Mike.C]

Paul,

Can't think of any reason why you would want a router table that isn't flat.

Snap. When I found out that manufacturers build a crown into phenolic router table tops I could not and still cannot understand why? It is said that the weight of the router installed in the table will pull it flat, but how do the manufacturers allow for the different weights of various routers i.e. the Dewalt 625 is a lot heavier then the Bosch 500 watt (forget the model number)?

Steve here is the post you are talking about.

https://www.ukworkshop.co.uk/forums/view ... hp?t=15033

EDIT I see Paul beat me to it :lol:

Cheers

Mike

 

[Lord Nibbo]

Paul,

Can't think of any reason why you would want a router table that isn't flat.

I could not and still cannot understand why? It is said that the weight of the router installed in the table will pull it flat, but how do the manufacturers allow for the different weights of various routers i.e. the Dewalt 625 is a lot heavier then the Bosch 500 watt (forget the model number)?


Cheers

Mike

It's nothing to do with the weight of the router, it's for the reason Argee says above.

 

[Steve Maskery]

Well you are more generous in spirit than I am. I think it merely because it is expensive to achieve the precision of flatness people like me would like in a plastic material, because of the way it cools. Perhaps I'm just being cynical. All I know is that it causes me problems. My router table has a track running at 90 deg to the main one, for use with my horizontal router attachment, and the the crowning means that the front end of my workpiece catches in it, because it's travelling downhill at that point.

I'd like a flat one please.

Cheers
Steve

 

[Paul Chapman]

Does anyone know which of the various makes available are flat and which ones are crowned? I'm not sure that it's always mentioned in the specs. I haven't bought one yet but when I do, like Steve, I'd like a flat one.

Cheers :wink:

Paul

 

[Mike.C]

LN,

It's nothing to do with the weight of the router, it's for the reason Argee says above.

Excuse me, but I was writing my post while Agree posted his, so I did not know what he posted.
I was also only repeating what both Steve and Paul told me in my thread, and these 2 members have also repeated the same above. In fact Paul said this in the very first reply to johnnyb, didn't you notice that?

If you knew what Agree says to be true then why did you not tell me this in my thread (link above), if you did not then you are only repeating what you have been told, just the same as I was.

Thanks for the info Ray.

Cheers

Mike

 

[steveal]

Could you not simply hang an anvil off your router?

 

[Slim]

Does anyone know which of the various makes available are flat and which ones are crowned? I'm not sure that it's always mentioned in the specs. I haven't bought one yet but when I do, like Steve, I'd like a flat one.

Cheers :wink:

Paul

I would have thought Woopeckers would be flat as it is aluminium.

Edit, I have just looked at the newwoodworker site. They say it is ground flat to within 0.002". Buy it from http://www.woodworkersworkshop.co.uk/woodpeckers.htm in the uk

 

[Steve Maskery]

Very rude words.

The Woodpecker is 1/4" shorter than the Rousseau, so I'd have to remake my entire table-top. Looks the biz otherwise.

:evil:

 

[johnnyb]

the plate from axminster(rousseau) is very cheap, in its favour(£17). unfortuneatly i have spent all afternoon fabricating some tee nuts for the sliding fence and have not followed the thread. the crowning is quite high. the lead in will catch as it must be .5mm proud the lead out is perfectly flush. i can only think the workpiece is intended to span across the two lumps with a feather guard above the slightly lower inserts to make sure this happens. what if you fit it the wrong way round your workpiece would rock everytime it left the plate. anyway my recess is perfectly routed. when new you can see contour lines in the top surface. i am yet to try it as i have no 1/2 inch cutters!!!

 

[Paul Chapman]

Does anyone know which of the various makes available are flat and which ones are crowned? I'm not sure that it's always mentioned in the specs. I haven't bought one yet but when I do, like Steve, I'd like a flat one.

Cheers :wink:

Paul

I would have thought Woopeckers would be flat as it is aluminium.

Edit, I have just looked at the newwoodworker site. They say it is ground flat to within 0.002". Buy it from http://www.woodworkersworkshop.co.uk/woodpeckers.htm in the uk

Thanks Simon. Yes, that one looks very good.

Cheers :wink:

Paul

 

[Paul Chapman]

I've just looked at the Trend website and see that their router insert plate is also crowned http://www.trendmachinery.co.uk/rti/ Perhaps andy@trend, if he reads this thread, could give us Trend's view as to why crowning the plate is considered better than making it flat?

Cheers :wink:

Paul

 

[andycktm]

It's like columbo with all the theorys :lol:
Does anybody know for sure 100% that the crowning isn't just a side effect of the machining process, ie holes punched out or pressed out?
If the insert is say £20 they are going to be made for 50p each so they are not going to mess about.I'm just adding to the theory i don't know myself.
Sorry argee :wink:

 

[Steve Maskery]

I've just looked at the Trend website and see that their router insert plate is also crowned

I'm pretty sure that the Trend Plate and the Ax plate are the Rousseau plate with a sticker on it.

I'm still fuming that the Woodpecker plate is 1/4" too short to fill the gap in my table. If it was 1/4" too big I could just enlarge the aperture.

Grrr.
S

 

[Paul Chapman]

I'm still fuming that the Woodpecker plate is 1/4" too short to fill the gap in my table. If it was 1/4" too big I could just enlarge the aperture.

Grrr.

Steve, could you perhaps cut a piece and glue it into the aperture (I assume the cut-out has a lip on it), re-inforce it from underneath if necessary, and then cut a new hole?

Cheers :wink:

Paul