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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: 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.

Rod

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.

Regards

Rod

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.

Regards

Rod

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.

Regards

Rod

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.

Rod

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

Emgee

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

Rod

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.

Rod

Thread: WHERE ARE THE SHAPER USERS ?
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

Rod

10/02/2019 20:50:41

Thanks Clive

That seems very promising. Apparently no parts missing and I now have a beeter understanding of how it should work.

I will clean mine out, and check the spring is not too strong, and hopefully that will cure my problem.

Thanks again.

Rod

10/02/2019 14:33:33

Hi all

I have an Elliott 10M shaper. Can anyone explain how the ratchet mechanism on the power cross feed works? Mine only works intermittently. There seems to be only one pawl and sometimes the feed advances and then retreats slightly and repeatedly with each stroke so I get no proper cross feed advance. I can only guess that the action should depend somehow on friction in the feed screw resisting the backwards movement (and I don't have enough friction) or my machine has somehow lost a second pawl. or perhaps I have not understood it at all.

Regards

Rod

Thread: Old screwdrivers - any use as a materials source?
04/02/2019 16:14:23

Hi

Grind a four faceted acute point on the end of the shaft to make what an old school woodworker would call a "Bird-Cage Makers Awl" - used originally for making small holes in thin wood without splitting it in the days when the whole cage was made of wood. Lots of twist and not too much push!.

I think Marples made these awls until the eighties. Useful now for making pilot holes for woodscrews. Works better than a bradawl in my opinion.

Rod

Thread: Myford 33t and 34t gears for metric threads
27/01/2019 11:11:25

Hi

I bought both 33 and 34T gears from the present Myford brand owner last year at one of the shows. I don't have any information about current stocks.

Rod

Thread: Straightening coiled small steam pipe.
09/12/2018 21:55:17

In his book "Tools for the Clockmaker and Repairer, Volume 2" John Wilding suggests a method of straightening wire which I have used with sucess on small diameter tube.

Briefly, find a 2" length of tubing which is a loose fit over the wire or tubing to be straightened and bend this short length slightly so that it becomes a tightish fit on the tube to be straightened (the longer tube). First straighten the longer tube by hand as straight as you can.Then hold the longer tube in the lathe chuck and spin at moderate speed while holding the short length in a gloved hand and move it up and down the length of the longer tube. I don't know quite how it works but the bent rotating tube just straightens out - like magic!

Rod

Thread: Big Numbers
07/12/2018 21:15:01

I love blowlamp's link to the US Treasury figures.

Does anyone know if there is an equivalent UK Treasury webpage?

It would make interesting! reading as the Brexit debacle unfolds.

Rod

07/12/2018 18:49:42

On 30 November the Guardian newspaper reported that an International team have measured the total amount of light emitted by all the stars in the universe in the 13.7 billion year history of the universe. Apparently the stars in the universe are so far apart that over 90% of the light emitted never hits any other body and forms a fog of background light that can be measured, enabling the total number of photons to be estimated. The estimate is 4 X 10 to the 84th power!

This is a really big number, in fact it is literally millions and millions and millions times bigger than any number I have ever heard of before. Do any readers have any other examples of big numbers?

Rod

Thread: What Material for a rear tool post
18/10/2018 21:36:33

Some years ago a contributor to the ME press ( I can't remember which magazine ) detailed a toolpost for a smallish lathe which he said was made from a grade of steel which was stronger than ordinary mild steel and which machined easily to a good, bright finish which was fairly rust resistant. Sounds like useful stuff for things that get a lot of handling.

I seem to remember the author was based in the US. Does anyone else remember this article? What kind of steel was it and is there a UK equivalent available here?

Rod

Thread: JB cutting tools .com
18/10/2018 21:09:47

+1 for good service from JB.

Both the older couple (no insult intended!!) were on duty today on their stall at the Midlands Show so no apparent problems. JB has been a fixture at ME and similar shows for some years and appear to have many regular and satisfied customers, including myself.

+1 for giving them a ring after the show finishes on Sunday to sort what is hopefully a minor hiccup.

Rod

Thread: Micro drilling
17/10/2018 17:31:27

Hi all

Centre drills are not ideal for spotting holes and they get less ideal as the hole gets smaller ( for example, the pilot gets very fragile.)

Better to use spotting drills - made for the purpose, with much stronger points and they are available in a wide range of sizes down to very small.

For example, "Kyocera" , a Japanese company, list them as small as 0.005" diameter (on an eighth-inch shank) and since you only need to use the point these would probably enable one to make a spot of only about 0.001" diameter if that was needed. Need good bearings in the drilling machine though!

Google "Micro spotting drills" Not sure about easy availability but someone will stock small spotting drills in the UK.

Rod

Thread: Todays Mystery Object?
20/07/2018 21:31:55

Tim

Interesting, I agree that the use of a beam of light does not of itself lead to greater accuracy, but by the use of mirrors to "fold" the beam, it does allow for a much longer pointer than a conventional (metal?) pointer could conveniently be. The longer pointer allows the measurement to be displayed on a longer, more open scale which can be read to a finer degree than a shorter cramped scale and this can lead to more accurate working?

I also agree with you about the lack of inertia etc but this not always the reason for using a "light pointer.", For example, in the Wheatstone Bridge device mentioned above the unknown resistance is not usually varying rapidly, if at all.

What do you think?

Regards

Rod

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