Stevenson Blocks...

Well I took the plunge and got a pair of Mr Stevenson's legendary blocks. These are accurately gound sections of hex or square bar now available with an ER25 fitting (the originals were ER32).

After the initial shock (they didn't come in cnc-lettered, velvet lined walnut cases), just carboard boxes, I'm rather taken by the little fellas.

I can see they are going to be a godsend for speeding up all sorts of simple indexing tasks, such as putting a square on the end of a rod or making hex nuts and screws. They could also be used for drilling handwheels etc.

One good point is that the corners of the hex and square are ground with small but apparently accurate flats. This means that (although the vertical distance will change) you can index through 8 or 12 angles.

One use could be as part of a grinding jig for shapening end mills etc.

For most uses simple stops that allow teh block to be rotated and replaced accurately will be needed, a milling vice with an end stop will suffice a lot of the time.

You have to fit your own closing nut, and of course I have just realised how useful it will be to have a nut especially for them so I can use cutters in my ER chuck at the same time!

A good way to add value to the set of ER collets many of us have already.

Don't tell John, he'll get over-excited

Neil

I am waiting for ER40 version.

Long wait then ....................seeing as I don't have any ER40 gear.

Hi Neil,

I have a pair of the ER32 jobbies and for most jobs, butting the end of the closing nut up to the vice jaws is all you need for quick indexing. Don't get too big headed John, but they are one of THE most usefull bits of milling kit i have come across.

Cheers Derek.

John

How about some ER20 ones, should be just about the right size for a BCA.

Phil

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I will second that !!

MichaelG.

Having aquired a set of er40's they look very well made and finished....do you make them mr stevenson?..

One thought though is it possible to have made a er40 nut that will take a er32 collet or er20?

then a taper fitting to put into the er40 hole to sleeve it down? to the smaller sizes

Just saves buying smaller er40s when I allready have them in smaller er's

Is this possible?

Probably more expensive to get a 'special' nut and sleeve made than to get a smaller block!

Now I have had them a few years, the point about needing extra nuts is well made.

Neil

Still no ER20 or smaller

**LINK**

I can't see any overall dimensions, so: to save me trying to scale fom the photos, could someone please advise?

Thanks

MichaelG.

I'm surprised there's enough profit in making ER40 or 25 blocks for hobbyists as I'm lead to believe that ER32 is by far the most popular?

You can however get parallel shank ER chucks for £15 or so from Arc euro which can then be held in your blocks. `I see they also do ER40 blocks too.

regards Martin

I got fed up of waiting for an ER20 version and made my own blocks to take DA 180 collets of which I have full sets of both metric and imperial.

I changed the design so they have 8 and 12 sides respectively.

Phil

Edited By Phil P on 07/01/2016 13:12:12

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Shows how dim I am.

It's only because of this thread that the penny has dropped and I now realise why 'Stevenson blocks' are called such.

Nick

My ER25 set is 35mm af and the machined portion is 42.5mm long plus a thread 17.5mm long thread if that helps, agree wholeheartedly regarding their usefulness.

Andy

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Thanks, Andy ... Just what I needed to know.

MichaelG.

The nut overlaps the block so you can't use it flat on the bed of a mill, that is why lots of people hold them in a vice.

Neil

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Oh "bother"

... I was hoping that was only true of the larger ER sizes.

Thanks for the info, Neil.

MichaelG.

If you bolt them flat to the bed to get repeatability to do all sides or some you will have to have register packing strips around the block or at least one side and end.

So if you have to do this then just pack it up to clear the nut.

As I keep telling my girl friend, "it's not rocket science " which pi$$es her off no end as she is actually a gen-u-ine rocket scientist. PhD, ASBO and bar, WC and chain

John - if you *really* want to pi$$ her off, tell her that "Rocket Science is easy - one equation - E=mc2; the tough part is Rocket Engineering - making the damn things work".

The other JohnS.

Not going to work with her.

She has built her own single engined sports plane from a set of plans, - no kit and flown it across the Atlantic single handed, not once but 3 time in total.

She has a CNC mill in the kitchen mounted above the washing machine