Member postings for Trevor Drabble

John,

Can spot 3 problems straight away ! One is that the wing nut is at the back rather than the front where it should be , and also, assuming one is right handed, starting will be almost impossible , because the pull cord is on the wrong side of the handle ! And finally, the pitch of the teeth is far too coarse for normal use, which may explain why it was bargain. Assume they had run out of finer pitch versions ?

Trevor.

Once again, many thanks gentlemen for all your inputs. The reason for the request is that I am in the process of negotiating the puchase of a S7with 3 phase motor of 1979 from my former employer, and needed to know what cost to start the amatisation from. I believe the machine is worth more than scrap value but significantly less than one sees similar 34 year old machines advertised for.

Trevor.

John and HTH,

Thank you very much , these are excellent pieces of information, are most helpful and have helped me enormously with my small problem.

Once again, many thanks,

Trevor.

Appreciate this may sound a strange request, but has anybody any idea how much a new S7 cost in 1979 please?

Many Thanks

Bill, Would like to offer the following suggestion. Since you dont especially need square internal corners, simply get rid of them. Fill the steam chest with an interference fit block of hardwood. Then carefully approach from above with a small diameter slot drill, with its centre directly over each corner point in turn. The block may then be removed since its function was to reduce the side stresses on the slot drill. Continue with the machining of the 4 sides of the chest as normal. You will then have an undercut in each corner which will allow the valve to fully enter the corner without interference.

Have drawn a simple sketch to explain. Not computor literate, so cannot get it onto these pages. If you supply me with your details, I will try and email direct, should you so desire.

Trevor.

Keith,

If you live any where near South Yorkshire, no problem in supplying your reasonable requirements free from me, but would apprecaite a donation to charity.

Trevor.

Mick,

I have some CI sticks available for welding CI with Oxy-Acetylene. If you can find anyone local to you to do the work, then would post to you. I have used them to weld a 6" bench vice and they have worked well for a number of years. Please be aware though, the process is "heat hungry". I pre-heated extensively and then needed a No25 nozzle to do the actual weld. Afterwards the assembly was then put into a bin full of sand to slow the cooling process. In addition,please note that in such a stressful application, even Nickel rods require careful application if ultimate cracking is to be avoided. As an alternative, in some magazines such as Vintage Spirit and Old Glory I have seen adverts for companies who specialise in CI welding. Perhaps this would be a more viable option? Also, have you tried asking JB for their advice on this application? Hope this helps.

Trevor.

Bill,

Unable to post picture. Please supply email address so that I may supply.

Many Thanks

Trevor

Correction, I now find it is actually attached. Hope it helps.

Edited By Trevor Drabble on 10/08/2012 00:30:47

Bill,

The only readily available information I know of relating to chucks and their keys, is that shown within 2 tables of a Cromwell Tools catalogue ( page 750 of 2010 issue). There are no technical details, only correlations between Jacobs/Rohm chucks and various chuck keys, the model numbers of which I assume are universal within the trade. If you feel it would help, I can take a snap and email it to you.

Trevor

Chris,

I believe you will find that this is a USA standard thread, a No3 x 48TPI UNC. As Engine Builder says, it would normally have a basic major dia of 0.0990, so 3/32 rod at 0.0938 is theoretically a little undersized, but you should get away with it. Tracey Tools ( no connection ) do a range of suitable UNC taps and split dies, with the carbon versions costing very little. For your information, die nuts are not meant for creating threads since they cannot be adjusted like a split die for fit, have less hook on the teeth as well as thicker legs. For these reasons, they are intended for cleaning worn or damaged threads only.

Regarding an M3 thread, this would normally have a basic major dia. of 3 mm ( 0.1181), thus making it unsuitable in this application.

Also, as stated, whilst there is no 3/32" ME thread, there is a 3/32" BSW x 48 TPI thread, which co-incidently has a basic major dia. of 0.0938, ie exactly the same as your rod, and again Tracey Tools have these available for relatively low cost.

I hope you will find the above info of interest.

Trevor.

Robin,

If I may add a little to this discussion, like Coalburner my theory is very rusty, but in essence, he is quite correct in that in a single phase motor the speed is determined by the number of poles, assuming the frequency stays constant, the theory being n=f divided by p. ie it is inversely proportional to the number of poles, and the number of poles in use at any one time is achieved by varying the 4 coil connections so as to achieve either 2 or 4 poles as required.Since my computor skils are virtually non-existant, I will try to describe from memory the theoretical connections in words. If you draw a square with a single coil on each side, and starting from the top of the square work in a clokwise direction, notating them as A,B,C and D. If you connect live between A-B and neutral between C-D this should give you 2 poles. If you then change the live connection to between A-D, with the neutral between B-C, then this should give you 4 poles. These 2 arrangements should result in the same flow through B and D on each occassion, and the flow A and C being reversed on the second occassion. I believe this is why you have the 4 wires + earth on your installation. These switching arrangements are perfectly feasible with a propriatory multi-pole switch such as theDewhurst you already have. In the interests of safety, I would suggest you also check this information with a better authority than I, such as a motor or switch manufacturer as well a local electrician/re-wind company who should be well versed in motor installations. In addtion, please ensure that the completed installation is fully tested by a suitably qualified person and that you receive the appropriate test documentation, it will be money well spent. If any of the foregoing are not available to you, then would suggest you investigate alternative solutions

I hope you will find the above of some use.

Trevor

David,

No disrespect intended, but are you sure the machine is a VMB? I have a VMB and to the best of my knowledge, Warco have not, and in fact still do not offer their version of this machine. My understanding is that it was only availble from Myford. I believe you actually mean one of the other VM .... variants which they do indeed sell.

Chris,

Can supply a copy of my VMB manual if you still need one.