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Member postings for Rod Renshaw

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

Thread: Workshop lighting
15/11/2019 18:22:39

LED batten lamps can be obtained from many retailers such as Screwfix and they resemble florescent tube batten lamp fittings and screw to the ceiling in the same way. They are easy to wire up (have Live, Neutral and Earth terminals), they consume little power and they start instantly and give a bright white light. Highly recommended! The active elements cannot be replaced, ( so the makers say, but an expert DIYer may think differently) the whole fitting will need to be replaced in due course but they are supposed to last a long time, so may be "fit and forget" in a mature worker's shop.

Thread: Grease Myford Super 7?
10/11/2019 12:36:05


That's always been my understanding . I have owned and used a Super 7 for over 40 years and have always only used oil. The instruction book only mentions oil. I think think the question has been raised on this forum before and the answer from everyone was "Only oil".


Thread: Rack operated tailstock
28/10/2019 21:12:48

I have one these ( same as HasBeans, except mine has 1/16" graduations) and I prefer it to the handwheel. I can estimate a depth to about 1/64" which seems accurate enough for drilling holes. The standard Myford handwheel tailstock has no graduations on the handwheel and the depth has to be estimated from the 1/8" graduations on the barrel itself. The other advantages are that the taper in the barrel is very easy to clean out and one can use a drawbar to secure collets and turrets in the tailstock. I have made a "bumper out" from a length of 1/2" steel bar with a brass tip on one end and a simple, but weighty, steel handle on the other. I keep this loose in the tailstock barrel and I don't miss the self-eject facility. The same bumper out is also useful in the headstock.


Thread: Evolution of a 4 Tool Turret
06/10/2019 18:41:35


Many thanks for the explanation.


06/10/2019 16:11:00


I have not come across the word "urge" used in this context.

Can anyone explain please.

Fascinating modification, I feel sure George would approve.



Thread: Any 5" Gauge Ground Level Turntable Articles or Advice?
08/09/2019 18:14:32

I was once shown a "writing hut" which the homeowner had built in his garden and which rotated to catch the sun on a home made lazy susan bearing. The bearing itself was made of 3 sheets of plywood each about 8 feet in diameter. The lower sheet apparently rested on the foundations and the upper sheet was secured to the base of the shed. The middle sheet had holes drilled in it in 3 (or possibly 4) concentric circles to act as a cage and children's glass marbles were used as ball bearings. I was told the bearings had indented the plywood a little in use, to make tracks in the upper and lower sheets of ply and that there was a "bolt" in the centre to form a centre bearing, the builder was not an engineer. I don't know what the shed weighed but it seemed strongly made and the owner was keen to demonstrate that the shed could be rotated with little effort even with 4 or so of his guests crowded into it.

it might be a bit homespun for a turntable but it does demonstrate what can be done with simple arrangements.

If the load on the turntable is 1,000 lb and there are (say) 200 marbles, it does not seem unreasonable to expect a marble to support 5 lb?

Thread: Myford
18/08/2019 21:22:45

These felts are still available for Myford 7s.

I understand that you can make your own and that chiropody felt ,available on the web, is a good material to use.


Thread: Heartbroken!
16/08/2019 18:05:13

Memory suggests that the chemical is alum, as used in cooking, but I can't remember the details. I seem to remember it takes quite a long time.

Thread: Dam Solution?
03/08/2019 17:53:46

I am rather taken with SOD's explanation for how siphons work using the analogy of a chain being dragged over an edge by gravity. ( I am sure JAs explanation using maths will be correct but I don't have the maths to follow it)

If we assume SODs explanation is a good analogy then I don't see any problem about water having nearly no tensile strength- which may well be true in general but in this case the water is in a pipe. The water has to stay in an unbroken length within the pipe because any break would cause a vacuum in any gap that formed. and air pressure on the water at both ends of the pipe would not allow that to happen- so the water behaves as if it does have tensile strength.

There is a limit though. It is well known that a siphon will not work over a "lip" of over 30 feet or so because the atmospheric pressure will not support the water column, and this may limit the use of siphons in large civil engineering situations. I am not clear how, or indeed if, siphons work in a vacuum.


Thread: Deburring small items after parting off
21/07/2019 09:56:59

Small tumblers are used by collectors and polishers of pebbles and semi-precious stones, and these are readily available from specialised shops and on the net.

Thread: Half hollow steel balls
28/05/2019 18:25:39

Hi Plasma

Is half a hemisphere a quarter sphere?


Thread: Precision Level or Precision Frame Level
03/05/2019 18:03:24

Hi Clive

Many thanks for your prompt and comprehensive reply to my question.

I just have to find one like yours now!

Even if I can't find an adjustable one, I now have an idea of the sensitivity I am looking for.

Thanks again.


02/05/2019 21:16:37

Hi all

After reading many of the contributions to this thread I am thinking of buying a level to use for "leveling" my lathe, and also for setting work up on my mill.

There has been much input on this thread about the sensitivity needed for these tasks and I find myself confused by all the different "Units" quoted by manufacturers and advertisers.

There seem to be units based on angles such as degrees, minutes and seconds of arc, and also degrees and decimal fractions of a degree. Then there are units based on offsets, and here there are many different lengths of baseline and some use Imperial measures and some use Metric units.

So how sensitive does the level need to be? and can the answer be quoted in many units so that levels from different sources can be compared? It is almost as if we could do with a conversion table, anyone know of one?

Thanks to anyone who can clarify this.



Thread: Fuse for "Align" slow motion mill table motor
01/05/2019 19:48:15

Pero and John

Thanks for your guidance on this. I have now fitted a 5 Amp fuse and all is well!

The fuse is a quick blow type which is all I was able to source locally, but I will order a few slow blow as spares.

If anyone else has this type of problem it may save time to be aware that the green indicator lamp on the Align transformer box only shows the presence of the mains input, and gives no information about the state of the internal fuse or the 110 v output.



30/04/2019 22:45:28

Hi all

I have an " Align" brand slow motion table drive on my mill, and as this required a 110v input supply and my mains supply is 240v I bought an "Align" step down transformer to go with it. This has worked well for some years, but then it stopped! I have tracked down the problem to a fuse in the transformer box which has blown - probably because I stupidly caused the motor to stall. I am hopeful that this is the only problem and that replacing the fuse will be a solution.

Problem is I can't read the markings on the Chinese fuse. The drive unit is a Model CE-500S, rated at 110v 90W. A simplistic calculation says 90W divided by 110V = just less than 1 Amp. ( The fuse is on the output, 110v side, of the transformer) Is a 1 Amp fuse enough or should I uprate the fuse to allow for startup current etc? Also, should this be a slow-blow fuse? The original fuse seems to have been a simple quick blow type with a transparent glass body and presumably it had a single wire inside it, but there is no trace of the wire now.

Can anyone offer any advice about this?

Thanks in advance.



Thread: M&W Straight-Edge Set
22/04/2019 19:43:10

I have a set, and a M and W catalogue which lists and describes these.

The test piece is a piece of plate glass and the test is to lightly press a straight edge against the glass and hold both up the light to see if any light comes through.

I read somewhere that a gap of one tenth thou inch will shown as a coloured light (I can't remember what colour!) and a larger gap will show as white light, assuming the background light is white.

My set seem to be very good when I try this test, probably because they were well made originally and I don't use them much. I suppose a professional toolmaker using them repeatedly would need to test to be sure his set were not wearing.


Thread: Machinery Directive and CE marking
06/04/2019 17:48:43

I am getting rather tired of all this willy waving

Thread: Crabtree B15 3 phase Stop / Start switch
17/02/2019 13:41:24


The latching relay drops out, because its power suppply is interupted, to give me a NVR action.


17/02/2019 12:15:38

Hi all

+1 for Les's approach. Many years ago when I first got a VFD I was told it was not considered good practice to turn them on and off at the mains too frequently as this would shorten their life. Similarly it was not considered good practice to have any switch gear between the VFD and the motor as this might generate voltage spikes that might damage the VFD. No idea if there is any evidence to back up these views but based on the opinion at the time I wired my VFD directly to the mains, (via a fused, switched outlet ) and wired the output of the VFD directly to the motor. I turn the mains switch on when I go in the workshop and need the lathe and turn the mains off when I leave the workshopfor the day. I have had no problems adopting this approach and my original VFD is still going strong.

I use the VFD's own low voltage switching terminals to control the motor to stop and start the lathe and control speed etc. I felt it safest to keep the mains and the low voltage switching far apart so I use only the stop and start buttons on the starter (which has no mains supply at all in this configuration, so the voltage of the coils is not important) and use a low voltage power supply and a relay wired to latch to simulate the action of the contactor.


12/02/2019 10:09:48

Thanks to everyone who has addressed my problem with the cross feed ratchet on my 10M.

I had a quick play with it last night and a combination of easing oil and taking up the slack has produced a reliable feed in one direction, but not yet the other. I will work on it again now I know how it is supposed to work and that some friction is required. I do wonder now if I might have caused the problem by oiling the leadscrew and its bearings some weeks ago!

Thanks again


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