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Member postings for Nigel Bennett

Here is a list of all the postings Nigel Bennett has made in our forums. Click on a thread name to jump to the thread.

Thread: Servicing a Myford 254
03/05/2019 11:17:09

I've no knowledge of the Myford 254, but in the Boxford 280 manual I have it suggests very strongly that you don't faff about with the bearings, but leave it to their service department.

However, they say - if you must...

"Pre-load condition may be checked using the cord & spring balance method, when a steady pull in the region of 0,68kg (1.5lb) for new bearings or 0,34kg (0.75lb) for used bearings should be obtained, with the cord wrapped round the spindle nose and all gearing disconnected from the drive."

I imagine the two arrangements are very similar - adjustment by fine-pitched collars to set the preload.

I changed my spindle bearings on my Boxford, and it's not a task to be undertaken lightly.

Thread: 2" Clayton Wagon help
26/04/2019 17:32:20

Quite a few folk (including me) have omitted the feed-water heater as it causes more problems than it solves. My steering wheel is fine relative to the regulator. Are your boiler feet set too low? Or is the steering column a tad short?

Thread: Bought a Boxford...
24/04/2019 14:47:27

Thanks for the introduction, and welcome to the fold! I built a 531 bike frame back in 1978. I won a road race on it the following year, and the rather sad-looking frame is still hanging up in my garage, rusty, cracked and with a stuffed bottom bracket shell. Can't bear to throw it away...

Good luck with your steam project. Tubal Cain, aka Tom Walshaw, published a couple of books on "simple steam engines" and they're well worth acquiring for the gems they contain as to how to go about it. I built his steam crane "Hercules" for my nephew and it was a very interesting project.

Thread: Removing a grub screw
15/04/2019 17:28:12

One method I've sometimes used with success is to batter in a Torx bit - it needs to be a tiny bit bigger than the hex socket, but not so much it swells the screw and binds it more tightly. The action of battering it in helps to loosen the grub screw, and then hopefully there's enough grip to unscrew it.

Thread: Jacob chuck jaws
30/03/2019 11:34:43

I don't think they're unusual, George - they look like perfectly standard sets of replacement jaws for No.34 chucks. I can't see a size on the packaging, but I'd guess 0 - 1/2" size. The rusty ones might clean up.

Edited By Nigel Bennett on 30/03/2019 11:34:59

Thread: Hydraulic test set up
04/03/2019 09:41:44

Make sure, if you've got a valve in between the pump and the boiler, that you don't kid yourself into thinking that the boiler is leak-free, when all you're actually doing is to pressurise the pipe between the pump and the (closed) valve...

Thread: Can opener - the holy grail in engineering?
04/03/2019 09:39:18

Karen came back from a "Pampered Chef" party (Sort of Tupperware but rather better) with a can opener. It's excellent as it cuts the side of the can and forms it over so that there are no sharp edges. Absolute gem of a design.

Thread: Bending cast gunmetal
10/02/2019 14:25:20

Heating up gunmetal to bend it is probably the problem. I recall trying to" bump up" a piece of drawn bronze bar, and heated it up first as if I were a blacksmith battering a piece of steel. The hot bronze fell to pieces when I hit it. Reading up about it after the event, it appears that bronze is (or my bit was) "Hot Short" which means it doesn't like being bopped when hot. It's likely that cast gunmetal will behave similarly.

If I was trying to unbend a GM casting, I'd try to bend it cold. If it broke, I'd silver-solder it back together in the correct position. Whether it's worth heating it up a bit after you've successfully bent it to stress-relieve it, I don't know as I'm not a metallurgist. A quick Google search on" stress-relief of cast gunmetal" suggests 300C for a while.

Hope that helps

Thread: Myford Change Wheels
31/01/2019 20:51:58

I've got some nylon ones off eBay for my Boxford 280; chap makes them for all sorts of lathes. Not had any problem. Change wheels aren't heavily loaded, so they're OK - like the OEM Myford Tufnol tumbler gears.

Thread: Crumbling Monkey Metal
20/01/2019 15:54:39

Mazak (Zamak if you're in the US) as used for a lot of zinc die-castings were very prone to crumbling away (Old Hornby Dublo stuff and many pre-war toys sometimes suffered). This was due to minute amounts of lead in the alloy causing grain growth. If the lead is below a certain concentration, there's usually no problem.

Thread: Use of Colour on Drawings
16/01/2019 12:43:54

Whatever you do, avoid the awful kids' crayon efforts that appeared in ME with Keith Wilson's GWRillian series. It certainly didn't help that production problems with ME at the time caused some of them to appear almost blank!

Yes, "We've always done it that way" line drawings with 2 or 3 views are well known and understood, but modern 3D CAD does enable realistic rendered images to be produced. All very well if you're only going to look at them on a screen, but it'd cost a fortune in printer ink if you're printing out a load of beautifully-rendered colour 3D images...

My preference (Assuming you will print drawings) is for standard orthographic views as line drawings (Avoid too many hidden lines - add another section view if necessary) and pictorial/isometric line views if needed to illustrate a point. Pictorial views can be rendered, but I think it's mostly unnecessary; it could be considered showboating because you have a flash 3D CAD system.

Thread: Barrier cream
15/12/2018 11:07:13

Howard's comment about them (rubber gloves, that is) being dangerous with rotating machinery is spot on. Also if you have a Bridgeport milling machine (I don't but I use one at the club) then it's impossible to operate the feed handles wearing rubber gloves.

Another thing I used to do (which was a very bad habit) was to very gently grip the chuck on my drilling machine to slow it down after I'd switched the motor off. Bloody stupid idea and Don't try it at home. Especially if you're wearing rubber gloves, as they grip the chuck like it owes them money and you could easily end up breaking yourself. I only did it once and I got away with it.

Edited By Nigel Bennett on 15/12/2018 11:08:38

Thread: Fixtures and fittings
05/12/2018 10:59:06

WDS, I think you'll find.

Thread: Scale Fastener Choice?
05/12/2018 10:55:29

I tend to use metric (cheaper) but have reasonable stocks of both metric and imperial fasteners. I just use what's to hand, and if appearance is important, I'll happily use a BA nut re-threaded with a larger metric thread. (Metric nuts are too thin to look right.) Where fasteners aren't immediately visible, I use metric cap-head screws for their strength and ready availability.

Metric hexagon screws are usually quite large in the head department, but that just means that they mimic the large head pre-war Whitworth AF to thread diameter quite well! You can always just skim off the "M 8.8" markings if it offends you - or make your own! However, their head height is, like the nuts, a bit thin for correct Whitworth appearance.

(Avoid imperial hexagon-socket countersunk screws at all costs - the size of the hexagon socket is too small to apply any serious torque to the screw. Metric ones are a lot better in that respect - but you still need a well-fitting, unworn Allen key.)

Thread: Unbendable casting!
01/12/2018 14:15:12

Many copper alloys are known as "hot short". This means that they don't take kindly to being battered when hot. I found this out myself once when trying to form a head on a piece of bronze bar. It simply turned to mush under my hammer! Hence forming copper alloys is generally best when they're cold.

Thread: Workshop security - CCTV
29/11/2018 11:10:36
Posted by Rik Shaw on 29/11/2018 10:42:52:

Sorry to hear that Tony but straight from the mouth of a DI quite recently after a nearby break in the best deterrents in order are:

Visible alarm system

Visible CCTV

Large noisy dog

Rik

You putting yourself up for this as a deterrent, Rik? How much do you charge?

Thread: For discussing the merits of alternative 3D CAD programs.
14/11/2018 11:22:29

£199 for licence only, £279 including maintenance according to the Mintronics website -they are the resellers in the UK.

https://www.mintronics.co.uk/webshop

Edited By Nigel Bennett on 14/11/2018 11:23:27

Edited By JasonB on 14/11/2018 15:40:06

Thread: Toolholders & Inserts
14/11/2018 10:55:00

Have a look at JB Cutting Tools. They make toolholders for the very commonly-available inserts such as CCMT and DCMT shapes. Bear in mind that there are also CCGT and DCGT inserts, which are ground and are really sharp, unlike the CCMT/DCMT types, which are really only suited to industrial-type lathes; a Colchester Bantam size as a minimum. The -GT inserts are intended for use on aluminium, but I've used them very successfully on all materials. You can take very fine cuts indeed with them, not something you can do with the -MT inserts.

Ebay is a source of the CCGT/DCGT and other shaped inserts; many of them come from China, so they may not be as good as European or Japanese ones - but they're often very reasonably priced.

Downside is that the -GT inserts are extremely brittle - I've bust more than one by accidentally moving the carriage and hitting the stationary chuck when I've been cleaning the lathe!

JB Cutting tools (usual disclaimer) are very helpful - give them a ring (01246 418110) to discuss!

Thread: Piston ring articles in ME: 4350 vs 4450
14/11/2018 10:39:35

Chap called Trimble also described the "Pinning open" method in ME 3735. I have used this method for three locos now, all with different sized pistons, with excellent results. I recall moving my 5"G Edward Thomas in the workshop a while ago when I was cleaning it. Some time went by and I had cause to move the reverser. There was an audible chuff - it had held pressure for quite some time.

I didn't use Trimble's brown paper idea; I simply coated my rings inside the fixture with Easyflo flux and held the whole doings at a very dull red heat for a few minutes.

Thread: Selecting a VFD for a Harrison lathe.
10/11/2018 11:47:43

Speak to the chaps at Transwave - advert on the right somewhere. Really helpful guys who know their stuff. I've bought two VFDs off them for a S7 and a Boxford 280. I've also heard good words from Newton Tesla as Norm says above.

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