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Member postings for Nigel B

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

Thread: Alternative to PC based Cnc controllers
12/04/2017 07:39:51

I thought that I could mount it inside the machine main casting / body to keep the noise down

Not a good plan to put an air cooled compressor in a small enclosed space, or to introduce a heat source within the carcass of a machine tool.

Nigel B

11/04/2017 19:17:40

Power drawbars, and presumably the gear selectors, tend to be transitory. They don't need continuous air flow at pressure to work. Provided there's enough capacity to operate once it comes down to how often you're going to be tool or speed range changing. Probably not that frequently.

Indeed. But oil-free compressors don't take kindly to this application - been there & killed a Wolf unit with a 25 l receiver in a very short period doing just this. Killed two of them, actually - the first one was replaced when it died, as it was presumed faulty. I was working part time for the company at this point & the first one came & went while I wasn't there. I read the booklet that came with the second unit & found it had a 15 minutes in an hour duty cycle. Unfortunately this enlightenmant came just as the second unit turned it's toes up. OIl-free compressors are OK for very light use, infequently, or they die young.

Nigel B

11/04/2017 17:56:53

found that the mythical "suitcase compressor" was finally in stock at Lidl as of yesterday. Clouds and silver linings etc. So now I have a means of operating the power drawbar and gear selection solenoids. The CNC gods smiled on me again.

Not with that compressor they havn't. Have you read the specs ? - 1.5 minutes operation, then 8.5 minutes rest to cool down ! No receiver. "Hearing protection required" This maybe OK for the occasional tyre top up, or football inflation, but it won't run a machine tool & survive very long.

The vee twin compressors on a 50 litre receiver that Aldi did recently would be more like it - you would still be deaf when it ran, but at least the receiver would keep the machine operating between deafening bursts to top it up. And, being a wet sump compressor, it is continuously rated. Unfortunately it also cost £100 more !

Retrofit looking good.

Nigel B

Thread: Bronze, Phosphor Bronze, Cast Iron or Graphite for LTD Stirling bearing
11/04/2017 09:58:28

The graphite we machine is man made from, as I understand it, a mixture of coke and pitch. The coke is ground to specific grain sizes according to the grade of graphite required. Other compounds may also be added, like iron filings or sulphur to vary the properties. The resultant thick paste is either extruded or isostatically pressed into blanks, then baked to form a carbon block. The carbon blocks are stacked, covered in deep layer of coke, then heated to very high temperture by passing an electric current through the stack - this converts the carbon to graphite. Improperly graphitised blocks have a higher resistance & are harder to machine & I understand that the graphitisation process is "one chance" process - if it is not done properly first time around it can't be re-visited..

The properties of the blocks vary depending on the mix & how it is processed - some are soft enough to be able to take chunks out with a teaspoon, while others are almost like ceramic & can only be worked with diamond tools - with many variations in between. My understanding is that these man made graphites are different to the natural deposits that are used for graphite lubricating powders - but my understanding may be flawed. When we are asked to supply graphite powders, these come from different suppliers & are physically different to the talc-fine dust that comes out of our dust extractors from machining extruded & isostatic blocks.

Nigel B

11/04/2017 07:50:16

I work for a specialist graphite machining company. so see the stuff (in various grades - and there are many, with widely differing properties) being machine daily. Most grades are easy enough to machine with normal metalworking tools - HSS, carbide inserts etc. For short run special profiles, form tools made from silver steel & gauge plate used unhardened also work. It is abrasive to the tools - a bit like cast iron. It is also very dirty, but (according to HSE investigations conducted at my employer's previous company), poses no particular health hazards and, in particular, poses no explosion risk as airborn dust as it requires the continous application of heat to cause it to burn. Motor brushes are mainly carbon IIRC, not graphite (we don't make motor brushes).

If you PM me the dimensions of the billet you require, I will see if I can get you a suitable piece of fine grained Isostatic graphite from the oddments bin. My employer is usually OK with this & only requires that photos or videoes of the finished item / machine are sent so he has the option of using them for publicity purposes. This grade machines to a good finish & parts can be made to close tolerances (we hold sizes to better than 0.01mm) - it is a bit dirty, mind !

Nigel B

Thread: Is it ok the hold a small lathe chuck in a larger one
07/04/2017 21:06:12

You could put the whole of a Super Adept in an 8" 4 jaw

To turn it into something useful ?

Nigel B

Thread: Boxford BUD restore
07/04/2017 15:04:21

I would be inclined to remove the spindle to clean out any old, hardened, grease from the bearings, check the gearing for damage (missing teeth from locking the spindle with the back gear to remove a stuck chuck are common), then re-grease and reset the bearing pre-load. The mid-60s CUD I inherited from my father had grease in the bearings, nipples & drillings that was the consistency of candle wax & took quite a bit of shifting. There is also a good chance that the back gear shaft will have been greased rather than oiled at some point, so that would also benefit from a good clean out & correct re-lube. Same goes for the saddle - anything with an oil nipple could well have been (incorrectly) greased.

Colour ? Your choice, but lighter colours make for a lighter workshop & something really "off the wall" could have an adverse effect on future resale value.

Good luck in your endeavours,

Nigel B

Thread: Is it ok the hold a small lathe chuck in a larger one
07/04/2017 10:06:40

The turners at work regularly hold a small 4 jaw in the normal, larger, 3 jaw as it is easier than swapping chucks.

Nigel B

Thread: Source for pneumatic fittings?
31/03/2017 15:22:49

Haha, sky hook, tartan paint...

Bucket of sparks for the grinder, a gallon of 10 thou backlash oil ("we havn't got any 10 thou in stock - go back & see if 2 gallons of 5 thou oil will do " etc. etc.

Nigel B

Thread: Air compressers
28/03/2017 13:05:43

only to be told that this was not an Ingorsoll Rand model

That looks very similar to a Clarke branded compressor we had at my last employment - might be worth a look on the Machine Mart site to see if there is currently one like that offered. MM do supply parts, but at a price and in their own good time !

Nigel B

Thread: repainting powder coated metal ?
27/03/2017 09:11:17

My local powder coaters bake old coated parts to make the remaining coating brittle before shot blasting the remains off.

If you can remove the loose bits mechanically & scuff-up the secure remaining coating, a two-pack etch primer should give a sound base to refinish. International Paints used to do a two pack etch primer for outboard motor bottom units that was particularly tenacious on aluminium castings (I used it brushed on to motorcycle alloy wheels to good effect), but it isn't cheap.

Nigel B

Thread: New pound coin
27/03/2017 09:03:32

I think the hidden security feature will be inside, something like a hollow section to alter the weight or balance.

Or it's electromagnetic "signature" - vending machine coin sorters have an inductive coil system to check this, along with the weight & size of the coin.

Nigel B

Thread: Machinery's handbook
26/03/2017 14:16:01

Words fail me!!!

Vandalism comes to mind !

Nigel B

Thread: Tailstock Turret Plan from MEW 253 - FOR DIGITAL SUBSCRIBERS
23/03/2017 08:31:46

I cannot see any problem with this design at all

There are a couple of points that don't seem great to me :

The index pin is parallel - this will have some play when new & will wear looser. Commercial designs use a tapered pin to take up wear ?

The angled block is located with countersunk screws only - better to have made the angled block with a bigger footprint & use pins for location, or to have fitted the block into a closely machined recess in the back of the body ? Unless using fitted bolts to give a location and fastening in one, isn't it usual to use fasteners to hold things together and pins, tenons, spigots etc, to give a positive location ?

Nigel B

Thread: Can someone recommend a mill cutter supplier
19/03/2017 18:59:42

We use Cutwel at work - seem to give a very good price/performance balance, wide range of sizes & next day delivery. Worth signing up for their e-mail alerts to get forewarned of the special offers ( buy 2 get one free or BOGOF often on HSS & carbide milling cutters).

Nigel B

Thread: Oh - What a Beauty !!
16/03/2017 09:21:20

The lights are in lieu of brakes.

Regenerative braking ?

Nigel B

Thread: Lidll
15/03/2017 09:04:29

My good lady has just purchased a polished granite slab from Tesco Direct AKA chopping board under £15 about usual breadboard size about half inch thick. Might have alternative use???

Maybe, but probably not the use you are thinking of !

I bought an Aldi one thinking it might make an "economy" surface plate. Checking the reflection of the store lights in the polished surface showed no obvious distortions, so it looked like it might be a possibility and it was cheap. But a visit to the CNC CMM at work soon revealed that it was far from flat - subsequently I tried a knife-edge straight edge in a "Union Jack" pattern across the surface. Daylight could be seen between the SE and the granite plate, so no feeler guages required to find the errors (it was substantially hollow in the middle).

Might make a nice cheeseboard, rather than a chopping board, but it will take a lot of work to make it a useable surface plate.

Nigel B

Thread: Hofmann dividing head manual
13/03/2017 18:28:39

Might be worth dropping an inquiring e-mail to Zeatz UK (used to be Zeatz Hofmann when I dealt with them at my previous employment) here : enquiries@zeatz.com

Never know - might have something at the back of a filing cabinet !

Nigel B

Thread: Doncaster ME Show and Warco.
10/03/2017 19:20:37

the cost is only amortized IF you buy something. It's the people who just go to tyre kick who cost you money.

A bit "Chicken & Egg" though John. On a large, non-essential, purchase like hobby machine tool equipment, many (most?) would like the opportunity to have a fondle of the product before committing to buy - I would not buy a £1500+ machine without having inspected one in the flesh, would you ?.

Shows have traditionally brought together competitors to enable direct comparisons to be made & the distribution of shows around the country allowed such comparisons to be made without excessive travel. For me, a visit to Warco (according to Google maps) is a 450 mile round trip, with Chester closer at 150 miles. Doncaster is 70 miles, so far more viable to go there to check out all the competitors in one place (should they choose to have a meaningful presence) than visit each individually. If I determine, after an inspection of the wares, that neither has a product that I am happy to purchase, that makes me an informed consumer, not a "tyre kicker". I cannot look over a new Warco machine at a show & go and purchase a new Warco machine from the internet cheaper from someone else. While the Chinese machines from various suppliers may look similar, that does not make them all the same.

I was considering swapping both my FB2 clone and RF30 for a WM18 type mill to free up a bit of space in the garage but determined, after a good look over the offerings at Doncaster last year, that I would rather stick with what I have - tyre kicker or informed consumer ?

With a reduced trade presence at Doncaster, I will probably not attend.

£0.02

Nigel B

Thread: Long Chang Mill Lubrication
09/03/2017 07:35:46

Slideway oil of 46 or 68 viscosity on everything except rolling element bearings, which would normally be greased. But not with copper-filled anti-seize assembly compounds ! Just use a "normal" bearing grease.on the spindle bearings.

Nigel B

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