Thread: Surface Plate Question

Well i think i may have found my plate.

I got a reply to one of the many emails i have shot off.

1000x630x150 grade 00 plate for $968 +GST. Thats ex Brisbane so i need to pay transport as well. They quoted me $77 transport for a 630 x 630 plate which is bloody good. Id imagine a 1000x630x150 couldnt be much more than twice that.

So thats a 1000x630x150 Grade 00 plate for about $1200 which i reckon is the best deal going.

They also offer a stand for it for $465 plus GST but i think i can do a good job at making my own for that price.

Can anyone di a better deal than this.

Simon

Sent from my SM-G900I using Tapatalk

Update. Delivery is $160 incl GST To Dandenong.

Its a 3 month wait as it will be in their next container shipment. Ill put a deposit on it for now.

Sent from my SM-G900I using Tapatalk

I think that plate is a good Simon. The big advantage with a new plate from a reputable seller is you know it will be flat. Any 2nd hand plate is really a unknown.

This video should give you some ideas for a stand. Robin Renzetti is the gold standard for precision on youtube

https://www.youtube.com/watch?v=yPhzp-OG67s.

Hi Simon,

I have read that in order to maintain the the calibration a surface plate shold be setup with the same mounting points as were ued to calibrate it. I don't yet have a surface plate so I don't know how much changing the mounting points affects the accuracy. Might it be worthwhile chasing the importer to see where the mounting points are on their stands? Assuming here that the stands they supply use a common set of mounting points to the stands the plates are calibrated on!

Have those of you with surface plates, checked the accuracy when you installed it or have you just said good enough for the work I am doing? And how have you checked the accuracy, repeat-o-meter?

Cheers

The Beryl Bloke

Yea thanks snapa.

The stand should be straight forward. Fiddliest bit will be the feet for the plate and the legs. I assume this plate will be no different to any other and will have been calibrated whilst being supported at 3 points.

I think i will make the stand with adjustable legs and casters so that when the adjustment feet are screwed down it lifts the casters off the ground. That way if i want to move it i can just wjnd in the feet until it sits back on casters.

50x50 rhs should be sufficient.

Cheers.

Simon

Sent from my SM-G900I using Tapatalk

Hi Bery,

You posted same time as i was writing.

Yep the done thing is to ensure you support the plate in the same location as it was during calibration. Usually 3 points. My understanding is that some manufacturers mark these locations underneath, however you can determine these points mathematically.

Wrt testing, Ray (i think) aquired a laser interferometer and used it to tested one they bought in a group buy a few years ago.

A repeatometer can detect local high and low spots but cannot be used for overall flatness determination. I think most people with plates just buy the best plate they can afford/justify and just assume it is as flat as they need.

Simon


Sent from my SM-G900I using Tapatalk

Thanks for the vid link snapatap. Some interesting ideas there.

I have scored an small (250 x 450mm) elderly unknown CI plate courtesy of AB and when I get over this bung knee problem I hope to start on a stand for it. I have some 40x40x4mm SHS that I plan to use for the frame. There's a spot under one end of a 900 mm wide bench with a 300 mm overhang that I'm going to make the stand to suit so I can tuck it out of the way this will allow me to make the stand about 300 x 800 x 750mm tall to give it a bit more stability.

Originally Posted by BobL

Thanks for the vid link snapatap. Some interesting ideas there.

I have scored an small (250 x 450mm) elderly unknown CI plate courtesy of AB and when I get over this bung knee problem I hope to start on a stand for it. I have some 40x40x4mm SHS that I plan to use for the frame. There's a spot under one end of a 900 mm wide bench with a 300 mm overhang that I'm going to make the stand to suit so I can tuck it out of the way this will allow me to make the stand about 300 x 800 x 750mm tall to give it a bit more stability.

Bob,

There is every likelihood that that cast iron plate isn't as flat as you might want it to be. Rather than waste time making a stand how about getting hold of one of Carbatec's boy's size granite plates ? https://www.carbatec.com.au/granite-surface-plate I have one and use it for most of my set outs and for checking the flatness of smallish stuff. It is also handy being able to place the plate on a surface to be checked.

Bob.

I have one of them too. Its very handy for small work and it just lives under the bench when not in use.

Simon

Sent from my SM-G900I using Tapatalk

Originally Posted by Anorak Bob

Bob,

There is every likelihood that that cast iron plate isn't as flat as you might want it to be. Rather than waste time making a stand how about getting hold of one of Carbatec's boy's size granite plates ? https://www.carbatec.com.au/granite-surface-plate I have one and use it for most of my set outs and for checking the flatness of smallish stuff. It is also handy being able to place the plate on a surface to be checked.

Bob.

Thanks Bob - The stand will have enough room to hold both the CI and a Carbatech size plate.

Originally Posted by simonl

50x50 rhs should be sufficient.
Cheers.
Simon

That will blitz it Simon, your plate will be the same size as the one you used at my place.
I made my stand out of what l had and l only bought wheels for it, so 60 or 65mm pipe,
50 x 6 angle and 50 x 5 or 6 shs, l put adjusters in the frame with 7/8" x 20 tpi threads with
ball bearings in the ends for less friction when leveling the plate.
I like your idea of the adjustable feet and done well should make it sturdy.
Anyway here is some pics of mine for you......
cheers, shed

Thanks shed. Were the supporting points marked on your plate or did you just calculate the bessel points from scratch?

Are the ball bearings to allow swivel for the adjustment pads?

Simon

Sent from my SM-G900I using Tapatalk

Originally Posted by simonl

Thanks shed. Were the supporting points marked on your plate or did you just calculate the bessel points from scratch?

Are the ball bearings to allow swivel for the adjustment pads?

Simon

Sent from my SM-G900I using Tapatalk

No, that plate had been sitting on a bench and had nothing to indicate where they should be, do a search for airy points, quite a bit of info out there.
shed

Originally Posted by simonl

Are the ball bearings to allow swivel for the adjustment pads?

Simon

sorry i missed that.
Yes the adjusters spin inside the cup holders, I got those cups from bunnings, they were for cupboard feet i think

"Bessel points" I hadn't heard that name before, thanks

Thanks Shed. My understanding is the plate should be supported at its bessel points not the airy points. I doubt it really matters for our use.

Airy points support a beam at such a location that the ends are parallel. However bessel points create the least amount of deflection in a beam.

Simon

Sent from my SM-G900I using Tapatalk