Member postings for Andrew Tinsley

I always use Gorilla glue (or its much cheaper versions). Squirt some in the hole and then some in the plug and assemble as normal. I have never had one shift after that treatment.

I have had similar problems to Alan in the past. Once fixed with the expanding glue, I have had no further problems.

Andrew.

Thanks everyone,

There are some very interesting facts that have come out of this thread. Ketan , as usual, has made some very cogent points, some of which I was unaware of. It is always interesting to hear what an insider in the trade has to say!

John, the description of your alignment method sounds like Rolley's dad's (Sp?) method. Like a test bar, this doesn't really tell you what happens when actually cutting metal, but using a test bar (with appropriate care), is a much simpler operation.

Whatever method one uses, the real test is how parallel can you turn in practice? Some 40 years ago, I used a test bar to align a headstock and it worked a treat. I never gave a thought to the problems that could arise. I now realise that I was very lucky in getting a good result. I simply ran a DTI down the bar and adjusted the head stock for zero run out! I didn't even check the bar run out by rotating it. There must have been someone looking out for simple minded folk.

John, I am not sure that simply turning a bar and checking for the same diameter at both ends is a wise move, unless you know that the bed isn't twisted. I must have checked maybe half a dozen amateur's lathes over the years. Only one was set up with no twist and that belonged to a toolmaker friend of mine who knew what he was about. Maybe someone with more experience than me can chime in here. I think that a combination of a twisted bed and a headstock adjusted to give the same diameter at each end will not necessarily give the same diameter in the centre? I freely admit I could be wrong here!

Thanks everyone for some really good comments,

Andrew.

Hello Brian,

Atoz make a double ended 2mt / 3mt bar. The specification is very comprehensive and looks good. Trouble is I am very suspicious of Indian made kit, having been stung before now with equally good speecifications that turned out to be wrong!

Andrew.

Hello Gordon,

That is interesting as I could not find one when I looked at Arc. It was my first port of call as usual.

Thanks,

Andrew.

Well some people get all the luck! Mind you it looks nice now, bet it looked horrible before you started!

Andrew.

In my thirties I was driving along in my Hillman Imp. Came to change gear and the gear lever snapped off. Good job I had a mole grip to get me home. just enough of a stub to get a good grip.

Andrew

Thanks Ian,

I have been told that the RDG test bars are in fact made by ATOZ. Although I don't know if this is true or not.

Andrew.

I would like to buy a 2MT and 3 MT lathe mandrel test bar. Or a combined bar for those 2 sizes.

All I seem able to find are those made by ATOZ of India. Now their specification sheets look good, But I have yet to find much good stuff made in India, apart from the excellent Zither chucks,

Does anyone have either of these test bars made by Atoz and are they as good as the spec sheet claim?

I appreciate that their are other methods of alignment (Rolley's Dad's method etc), but I would prefer a direct measuring system if possible.

Regards,

Andrew.

I am still working on a 920 lathe for a friend of mine. It came on a stand which made the cross slide to be 4 inches above my elbow. Too high you might think, no not a bit of it. It now makes me realise how poor my ML7 and ML10 are on their Myford stands.

There is no problem with back ache crouching over work.

Andrew.

Hello David,

Thanks for your comments. Providing you get the covers off, then spotting an EMC filter on the input of the VFD is simple. I am glad that one does not have to do a filter on the outgoing. I didn't think you did and it would tax any filter to get rid of the HF generated by the Fourier transfer function for rapidly switched current. I misunderstood one of the replies thank goodness for mistakes sometimes.

Regards,

Andrew.

Hello Murray,

Thanks for the Schaffner information and supplier. The price of the EMC filter is damn cheap compared to others I have seen.

Unfortunately I have gone for Siemens micromasters (420 and 440). Plus an odd Telemechanique VFD. The Siemens filters are eye watering and I have yet to find anything for the Telemechanique.

Regards,

Andrew.

So do you need filters on the input and output? I would imagine that a relatively simple 6 amp or so bog standard filter would do on the input and a fancy 3 phase and neutral style filter for the output? Am I getting this correct? Oh not to mention the screened cable from VFD to motor.

I just remembered the controversy about which end to earth, or both ends? Another thorny problem!

Andrew.

Hello Mike,

I was thinking of nasties going back along the supply lines to the VDF. Unless I have misconstrued, there is equal problems with the O/P of the VDF. I am beginning to regret asking as it seems that problems are growing like Topsy!

Regards,

Andrew.

P.S. I will try running without EMC filters for a start and then see what is needed to tame the VFD!

That is very interesting. I was under the impression that the filter went on the mains input side of the VFD (in my case single phase). So do they go on the three phase o/p side of the VFD? You live and learn!

So Muzzer and Jon, where did you get your relatively cheap filters from? Blowed if I can find a reasonable priced supplier!

Thank you both.

Andrew.

I appreciate that screened cabling, even for short runs is important.

Andrew.

Some VFDs come without EMC filters. I presume I need to fit one before I swamp everyone around with RFI?

Two queries, a lot of EMC filters that I am familiar with have capacitors down to earth. This is likely to trip earth leakage breakers when starting up an electric motor. Are there other types of filter that get around this problem? I don't like operating without an earth leakage trip!

Secondly, the cost of EMC filters seem to be anything from half to several times the cost of the VFD unit! Am I looking at the wrong type of EMC filter? A quick glimpse at the filter fitted to a Siemens 440 VFD appears to be just a very large ferrite ring plus a few turns of heavy duty wire. I have not had the unit apart to see if there is anything else in the filter.

Any experience with these problems or am I worrying over nothing?

Andrew

Hello Everyone,

Just for the record. The pulleys are newly made, pity about the incipient splits! The centre bore was cut with a hole saw and it isn't concentric. So a faceplate job is required to true up the bores. They may as well left me to do the bore on the lathe.

Andrew.

Thanks for the ideas so far. It seems that my initial ideas were not the best, as I suspected. George you are quite correct about the application of the pulleys, so a low tech solution seems fine.

Everyone doesn't much like the use of "engineering" grade nylon for the bush. So I shall see if I have any acetal / delrin or even oilite for the bush material. The Nylon came with the pulleys so I never gave it a second thought.

I most certainly am not going to thread myself between wheels and pulleys to do the replacement in the tower. I can certainly thread my way in, but getting out is an entirely different matter! Guess how I found that out?

Thanks everyone, your input is much appreciated.

Andrew.

I have been given a job to do. There are two wooden pulleys about a foot in diameter. They have been nicely turned with a rather rough 3 inch hole in the centre.

I have been asked to bush the holes with nylon and bore a hole for the spindle. Not a difficult job you may think. However the pulleys are showing signs of splitting and I fear that if I press the nylon bush into the pulleys, they may split.

I intend to glue and screw some aluminium discs each side of the pulleys to try and prevent this. Now what adhesive should I use? Epoxy with lots of keying scratches on the inside of the aluminium disc?

The other problem is retaining the nylon bushes. I dare not have a force fit for fear of splitting the pulleys. I shall probably have the hole in the aluminium discs, such that it overlaps the nylon. Now is there an adhesive I can use to secure the nylon discs into the hardwood pulley, as a belt and braces solution?

I have a nasty feeling that all the above is not the best approach. Does anyone have any better ideas please? I have probably been lumbered with this job in desperation, from the tower ringers. I used to ring bells until my muscle wasting disease got the better of me! But it seems that I have not escaped from working on the bells.

Andrew.

Hopper thanks for the heads up on scraping in the bearings on the ML7. I did manage to get my own ML7 pretty close, but it was far more good luck than skill. Which is why I was a bit leary at doing someone else's ML7.

I have a brand new set of white metal ML7 bearings which I am keeping up my sleeve in case I really make a mess of the job.

Thanks,

Andrew.