Member postings for David Jupp

Dyneema is a highly oriented Polyethylene. Though incredibly strong, it will still be subject to creep in this type of application. Though it may be UV stabilised, I would expect it to still suffer from UV attack in the long term if exposed.

At room temperature, such polymers are not all that far away from their melting point - so creep is always an issue to consider.

I've gone for sockets and light switches at approx 1m above floor where I've had building work done. I first saw this used over 30 years ago in some then new areas of Peterborough - great for the elderly, saves bending down. Light switches fall naturally at 'hand height' for adults, and can be reached by small children.

Read this before adding lube to your keyless chuck !

Part way through a very basic interface (more of a connector really, or mainly) to control Denford Novamill stepper and spindle from PC parallel port without having to replace stepper drivers or DC spindle drive.

Sorry, not aware of a cross reference list - though it must exist. I'd be interested if anyone has one.

I guess there may be some S grades that don't fall neatly into a single EN grade - perhaps optimised for some specific reason...

Typically the S series are ordinary (old) EN materials, but with more inspection/certification and may also be to a tighter chemical analysis than the 'bog standard' material.

For example, one customer users S97 or S154 if EN25 is not obtainable - being aerospace certified it costs a lot more though.

Plating/coating in general can cause threads to jam if the plating thickness is too great. I do some work with a company that occasionally makes specialist coated fasteners, they deliberately make the threads to the 'slack end' of tolerance so that the coating give finished parts to the required fit (whilst still meeting strength spec).

BSI do have a lot of withdrawn standards still available for purchase - (won't be cheap, but should be definitive if they can help) see this for contact details of their knowledge centre.

7S 1 1964 replaced 6S 1 1953

Edited By David Jupp on 19/05/2014 16:32:20

There are plenty of free ones, some of which are very capable indeed - the biggest issue I have found with free ones is getting help, clear instructions etc. The examples/help (where there is any) tend to be written by very experienced FEA analysts and/or software geeks - net result can be that getting started can be an absolute nightmare.

Hopefully you'll find somebody with experience to help you get started with a particular package.

No - SMEE are showing other aspects this year.

NIR method used is unlikely to work for identifying metals.

A chamfer on the end of the pipe can make starting the threading easier too.

Sunday for me this year.

I thought MPI only used for ferrous materials... would not expect it to work for copper.

I have a Novamill awaiting re-commissioning, I'd be interested in the design if you decide to publish.

Looks like they started out the same, but have been copied incorrectly at some point

2) ought to be (SFM*12)/(Dia*3.142) which is equal to 1}

What do you mean by 'integrate with AutoCAD' ? Just accept output from it to work with, or do you want embedded CAM where changes to the CAD design can ripple through to the toolpath with little effort ?

An awful lot of CAM software will accept DXF input - even controller software like Mach3 and I think Linuxcnc will accept DXF input for profiling at least, without actually needing CAM software.

Will you need 3D toolpaths, or just profiling? If 3D, is your work in AutoCAD compatible with that need (many use AutoCAD solely as a 2D system)?

Will you be using only your own CAD to program from, or will you be accepting files from others (perhaps originating form other CAD systems)? Once complete, will designs remain fixed for manufacture, or will they go through many iterations or variations?

CAM software can be 'less than straightforward' to get to grips with - perhaps look at some trials to see which seems most natural for you. Look at user forums, discuss training options with the vendor - help to make the most of the software will probably be at least as important as its technical capabilities.

Cost is likely to be a factor to consider - prices vary enormously, some charge for maintenance.

It's a bit of a minefield - goo luck.

James Walker web site offers a free 'O Ring Guide' covering materials, housings etc. Other manufacturers may also offer similar technical material.

It's amazing what can be accomplished with rollers (scaffold pole, heavy walled pipe) and a lever of some sort - but take things very slow and carefully.

Aldi had machine skates for sale not so long ago - probably fine on a smooth firm floor.

The problem is often as much stability (tipping over) as it is weight.

It's fairly common for a bearing to 'walk' round in the housing - particularly as one of the bearings needs to be free enough to move axially (differential thermal expansion of shaft vs. casing), yet ideally it should be tight enough that outer race doesn't rotate in housing.

I'd try the bearing retainer too. John Stevenson does lots of motor repairs, perhaps he'll chime in with some advice.