How tight is tight

[Stuart]

Ok here is the problem
On my Myford I have had one of the angular contact bearings fret and make a devil of a noise ,lack of lube was not a problem on these drippy beasts

Ok ripped it down to find these are the 7007 series's  with Linda,s house keeping now short of  £170 for the pair, I stared to look round for info ,note we are talking about the outboard bearings not the bronze one

The book of words supplied with the lathe is of little help as is for a small bore S7 they just say adjust preload ? To much will cause wear , so out with google to find out more but alas my Google fu failed me.

I have found a comment tighten up the coller hand tight ,that's not a lot of use as I have very strong grip so hand tight for me would be quite tight .

Another stated using the Allen key tighten the coller

Now Myford did sell a pin spanner for the big bores but it has a 100mm long handle on it. RDG still sell them, if did pick one up from Nottingham before the closed so I do have the tools.

For info there is a shim between the outer races to allow the pre load and let the oil in , it's split

So how much pre load to apply

I have looked around the sites on replacing mini lathe bearings with AC ones ( arc and others ) but all they say is set the pre load. the same info for my mill on the same site on the strip down page again just set the pre load ?

Ladies and gentlemen I await your response


Stuart
AKA lordemond

[steamer]

Stuart....Are these bearings sold as DU?   Put another way.. Do they have a bearing number and are they sold as a matched pair?....

If they are DU, they are a matched pair, and when assembled correctly, the races touch each other...and it really doesn't matter how tight you tighten them....

NOW.....if they are non matched pairs.....sometimes called "magneto bearings" and sold separately...then how tight is tight is a very real concern,

The short answer, just enough to take the play out...and no more.   As I recall the bearings on the Myford are right next to each other, so thermal expansion effects of operation should be negligible.

If they are separate bearings, and it sounds like it....put a dial indicator on the end of the shaft and adjust until it doesn't have any play axially...but no more.  I am sure there must be a minimum radial play dimension to allow for bearing clearance on the front bronze bearing...but I don't have the bearing adjustment procedure for a Myford in front of me.

Dave

[fcheslop]

Just had a look round myself as its going to be a thing I will need to do one day and can sympathize.
The only thing I found was here right at the bottom .
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDAQFjAA&url=http%3A%2F%2Fwww.astbearings.com%2Fproduct.html%3Fproduct%3D7007C&ei=kZ7SUqXOLuiO7QbQwIDYDw&usg=AFQjCNGBpA5vBTA4eSZFeD1-1gSt1AeAvw&sig2=BSPK9DU1YWFWrBBEVa4gWQ&bvm=bv.59026428,d.ZGU

[Graham Meek]

Hi Stuart,

The info given by Myford's handbook is not much use really when setting this part of the bearing adjustment, what you need to aim for is to adjust all the play out of the two angular contact bearing and no more. The angular contacts "Back to Back" as these are will give a satisfactory service with-out the spacer, BUT, without it, it will not allow the oil in. You could make a spacer for the inner two tracks of the angular contacts either the same thickness as the outer spacer or about 0.05 mm thinner if you want to add a small amount of pre-load, but I would not go any further. This last option was what I did when I had my Myford S7, the bearing pack is then a solid item.

My best regards
Gray,

[Stuart]

Thanks guys

Dave
There are two bearings back to back and come as a pair but you can get them as a single ,but i have them as a pair

fcheslop

As you have found out information is very sparse

Gray

Yes it's the shim that is used that upsets the apple cart but I think I will go with just take the play out using a dial indicator
To comment on making a shim for the inner race would require some preset fancy grinding to ensure that it is truly parallel and will not cause a twist

The ones that failed were constructed like a magneto bearing ie the race could be disassembled that how I noticed the fretting wear

Stuart

[steamer]

Stuart,

A duplex pair can be disassembled also...but shouldn't be mixed up.  They are ground such that when you tighten the bearing nut, the outer races touch first, then the inner races at which point the exact amount of preload is established.    These are expensive!....and they are a truly Matched pairs...not just two single bearings which is what I was trying to get on about.

Did your bearings come in a common box and have a part number with a DU or DB letters in the part number?

Dave

[Stuart]

Dave

these are they
B7007CTP4SDUL Pair of Precision Angular Contact

and were sold as a pair in one box

Hope that helps you

Stuart

[steamer]

OK....DU...Universal

The preload is built into them   You can't over tighten them if installed correctly in an appropriately designed assembly.

The races touch....and that's it.

Got a drawing of the installation?

If not which one of these diagrams matches what you're doing?

http://www.br.nsk.com/upload/file/NSK_CAT_E1254f_148-151.pdf


Dave

[Stuart]

Dave

Back to back DB

But here's the rub as Gray has stated there is a shim between the outer races with a gap in the ring at the top to allow oil in , oil nipple at the top between the races . It's about 15 thou.

That's the quick version but I will post up a diagram asap

[Stuart]

Dave hope this explains it

note the spacer it has gap for lube oil





the shim is part 30
note this is a S7  the big bore is well bigger

race is 62 x 35 x 14 in metric bits

Stuart

[steamer]

Well....I can understand the lack of clear instruction.   I would use the indicator method I described to take the lost motion out with the center adjusting nut...then use the threaded collars to set the gap on the bronze bearing.   Does that sound right Graham?    You're a machine tool guy from way back..and you've owned a Myford.

Dave

[Graham Meek]

Hi Stuart,

Is the shim exactly 0.015" ?

The reason I ask is that the following site has some shim washers listed, problem is they come in stock sizes and quantities of 100, (don't worry about the quantity for the moment), if you use 2 off 0.2 mm shims then using their tolerances this will suit 0.015" (0.381 mm) as the shims are rarely dead on size. As regards quantity just give them a ring,  tell them you are building a special piece of equipment and can you have a couple of free samples of the size shims that you need, offer to pay the postage, I have done this many times with them in the past when I was working, they are usually very helpful.

http://www.springmasters.com/sp/shims-support-washers.html

Shim size is 35 ID x 45 OD x 0.2 thick.

Hope this helps,

My best regards
Gray

[Stuart]

Dave I have uploaded the pdf to be a bit clearer

Gray

As I am in the house it was an approximation but Monday I will measure it and see what I can do

got down to WS  its 0.6mm


ouch £ 15 min order plus p&P plus vat

but the price of the bearings I will have to think

Stuart

[steamer]

Thanks Stuart,

I understand it.   It eliminates the need to use matched pair bearings and lets the oil get in...which as Gray said, is why the shim is there   But....it also makes setting the "preload" rather subjective other than measuring the overall axial clearance with  a DTI.

But.....How many millions of these lathes are out there?....    So I guess they work right?

Dave

[Stuart]

Dave
I have got to agree with you its the hairy fairy way they tell you how to do it , its subjective with their method but not with yours

but as you say there are a good few out there maybe I am being to cautious with the cost of the bearings , Yes I am glad its not a Colchester lathe with Gamet bearings @£4500 each or a Monarch 10EE at who knows the price but on a pension  they are expensive to me and I do not what to be repairing my lathe but using it


Gray

I have found a site that has no min order for shims so a pack of 0.2mm ordered to do a test to get the outer and inner races to line up


Stuart

[steamer]

As a brief aside, the South Bend procedure is not that far off from what we've discussed.  Hurray for Pragmatism!

 

Dave

[Jo]

Yes I am glad its not a Colchester lathe with Gamet bearings @£4500 each

  I will look after mine then. Also be glad it is not a Schaublin Mill that Eric has just discovered that the knackered spindle bearings are also well into four digits  .

Jo

[steamer]

That would be the source of the love/hate relationship I have with the Swiss stuff....sorry Florian...

Dave

[steamer]

Something to be said for pragmatism....

http://www.lathes.co.uk/southbend9-inch/index.html

Dave

[Hugh Currin]

The thinking with the shims are to space the inner race the same as the outer? If the same thickness then a matched pair of bearings should be set.

Would it work to cut shims from shim stock for both the inner and outer? I'd think that would better assure the same thickness?

I've thought about doing something similar with non-matched bearings. Mount them back to back, maybe just ball bearings, and clamp together. If this would create a heavy pre-load then shim so they are slightly loose. Then carefully measure the end play and make a shim this thickness. Put the shim in place and re-assemble with pre-load holding inner and outer races solidly. Do you all think this is feasible?

Thanks for the input.

Hugh

[BaronJ]

Hi Guys,

I don't know if it helps,  on my Myford S7  the bearings when taken out and the shim removed have a perceptible gap between the outer bearing cages.  Also on mine, when cold, the spindle is quite tight in the bronze taper at the chuck end, however it rapidly loosens after running for a few minutes.  I find it very difficult to adjust but it has always been tight from new.

[Graham Meek]

New angular contact bearings, especially a matched pair will have no perceivable gap between the outer tracks, any degree of pre-load built into the bearing by the manufacturer will be on the inner races, which you cannot see.

Tightness of the Myford spindle is down to the adjustment of the front bearing, it is adjusted by moving the whole angular bearing pack forwards towards the front bearing via the locking rings. This adjustment is not to be confused with what Stuart has originally asked.

To adjust the front bearing the whole bearing pack is adjusted towards the change wheels until the spindle just starts to lock up in the front taper bush, the inner most locking ring is then slackened by a 1/4" measured on the circumference of the locking ring. The rear locking ring is then tightened and the spindle should be correctly tightened.

Can I offer a tip when dismantling or adjusting things such as this, if you scribe lines on the locking rings and the headstock casting before you start, if you should get it hopelessly wrong you can always return things to where you started. I apologise to those who may be experienced in such matters for trying to tell them how to suck eggs, my advice is aimed at the person who may be afraid to make such adjustments and continues to struggle with his equipment when really there is no need.

My best regards
Gray,

[Graham Meek]

I had better add that these adjustments should always be carried out with a slack driving belt.

Gray,

[BaronJ]

Hi Gray,

Thank you for your explanation for the adjustment of the front bearing.  This is exactly the method described to me a long time ago.
Whilst I understand this procedure, what happens is, if I make the adjustment when the lathe is cold, there is perceptible play when warm.  If I make the adjustment when warm the spindle is tight to rotate when cold.  By comparison a friend who has the same lathe, the chuck can be turned more easily when cold than mine.  His suggestion is that my lathe hasn't done as much work as his even though my Myford is more than thirty years old.  The lathe was stripped and cleaned down about three years ago just before I retired.

You mentioned marking things before dismantling.  I put a paint marker spot on the adjustment rings to try to judge how much the spindle moved when adjusted.  You mentioned 1/4".  That amount is just about the difference between a loose spindle and being tight.

Your note about the belt is apt, though I make a habit of taking the tension off when not in use.

 

[Stuart]

Gray

I have decideded as I have a matched pair which is marked up by SKF I will wait till the shims arrive measure the outer again and select the inner ones to match and install as solid unit with the manufactures pre load locked in so to speak.

From what Dave has said it look like the design was to for fill two things
1 to get oil in
2 to enable them to buy single bearings

Hence a cost saving

I will post when it's back together ,with the method used

Many thanks to all who have taken the time to contribute, as usual I have learn a lot as to why it was done and the design limitations , and the reason why


Stuart

[Graham Meek]

Hi Baron,

No bearing arrangement, unless it is specifically designed to accommodate temperature variation is going to be able to accommodate large fluctuations in temperature as is usually the case in the Home Workshop. My own Maximat Super 11 will tell me it is a cold morning with a pronounced difference in the whine of the geared headstock, and this is in a worksop that is thermally insulated, double glazed and with a 5 degree C background heat.

If your friends lathe has done more work than yours, then yes, the bearing wear on the front bearing as well as wear on the angular contacts are all going to add to the clearance in the system, especially if the machine has never had the bearings adjusted from day one. If your friends machine was adjusted and had an identical temperature environment then I would expect similar results, but you cannot compare one machine with another without these considerations.

When I had my Super 7 I encountered this problem early on and in order to keep some stability in the temperature I used 2 X 40 watt light bulbs wired in series, these were placed under the lathe bed. The lathe cover was then draped over the lathe followed by an old curtain. It is surprising what heat these two bulbs deliver, bearing adjustment was carried out one morning after using this set up for a few nights and I never ever had a tight spindle from then on, nor was it too loose during a workshop session. The bulbs were dispensed with during the summer months.

As regards marking I use the end of my rule and a scriber, the marks are dead in line and it is not possible to return anything other than dead in-line.

My best regards
Gray,

[steamer]

That all seems quite reasonable Gray.  Thanks.    Take a look at all that Stuart and I am sure we can progress.

Dave

[BaronJ]

Hi Baron,

When I had my Super 7 I encountered this problem early on and in order to keep some stability in the temperature I used 2 X 40 watt light bulbs wired in series, these were placed under the lathe bed. The lathe cover was then draped over the lathe followed by an old curtain. It is surprising what heat these two bulbs deliver, bearing adjustment was carried out one morning after using this set up for a few nights and I never ever had a tight spindle from then on, nor was it too loose during a workshop session. The bulbs were dispensed with during the summer months.

As regards marking I use the end of my rule and a scriber, the marks are dead in line and it is not possible to return anything other than dead in-line.

My best regards
Gray,

Thank you for your notes:  The workshop has a frost heater and rarely gets below 48F.  Though I can soon rig up something to provide additional heat.  I too have the original Myford thick vinyl lathe cover which is getting a little tired now.  Since you mention that you had similar behaviour with your S7 I'm not going to worry too much.  At least everything else seems to be fine.

Based on your final comment I have now scribed a line through the paint spots, though for the time being I am not going to play around adjusting anything.

Your wisdom is much appreciated.

 

[Stuart]

Well Guys and Gals

the jobs a good un just barley a whisper at speeds above 2K the motor makes more noise 

the plan went oolong the line as commented on by Gray i ordered up some shim washers from a different place http://www.springfasteners.co.uk  who are Caleb Components   i had to order a pack but they have no min order and the P&P was £3.25
 the total with the Vodka And Tonic came to £9.84   ordered on line Sunday arrived today Tues so good service for a small order.

As Gray stated they are rarely on size the pack of 30 varied between 0.176 mm to 0.197 mm so a sort and match was done and the stack gave me a pre load locked up solid of 0.05mm

anyway I can see why Myford use the method they do because its was a pain in the butt to get the new shims in without trapping them off centre, I had to put the main shaft in backwards form the left hand end to locate the shim bearing stack whilst I pushed in the inboard race  yes I know it seem backwards but in practice it was easier to do it that way , i did offer it up the other way but it was no good

whole rebuild took about 1 hour inc sorting out the shims and as some of you know the tumbler reverser has to come off along with the first two transfer gears ( banjo can remain set ) the back gear lever has to come off  as well to allow the lower closer to drop down to allow the pulley back gear cluster to come out , a point to note flip up the back gear locking lever on the spindle to allow the two to separate , use your c spanner to push the out board bearing pack to the left ( note you have released the lock nut and removed the gear from the out board end else you will not be able to move it ) this give just enough room to wriggle out the pulley assembly

Please note these are my findings with a Myford connoisseur poly belt drive yours may vary as they were not all made equal

Again I must than all who gave me the information that I needed to get this done

BTW Gray I mentioned the tumbler reverse but as you know mine is fitted with one of your dog clutches , But i mentioned it for those that do not have the dog clutch fitted ( shame on them  )

Stuart

[steamer]

Glad it worked out Stuart!.....Thanks for the help Graham!

Dave

[Graham Meek]

Hi Stuart,

I am glad I could be of help and glad it has all worked out for you, I am sorry I did not put 2 & 2 together and remember that you are Stuart with the Connoisseur, I must apologise.

Having dealt with many tens of people over the past 12 months as regards the various screwcutting clutches that I have designed I must admit I have lost track. I decided this morning that It was time to call it a day on any more designs, I have recently completed clutches for the Compact 8 and the Wabeco D6000, it is now time to move on and build some engines.

Any chance we might see the finished Connoisseur Dog Clutch as up until now I have only seen it in drawing form?



My best regards
Gray,

[Stuart]

Thanks Dave and Gray

I will take it off and clean it down and post a pic over the next couple of days so stay tuned


Stuart

[Graham Meek]

Hi Stuart,

An in-situ photograph is OK with me.

My best regards
Gray,

[Stuart]

Here you are Gray







the trip lever is still on the lathe

I have taken it off to make a few bits as they are a bit wee so the rpm has to get up to near top whack 3k RPM  at that speed its a bit on the tabs but as you know its only a 5 min job to swop over, for my setup its only of use in bottom belt 150 -1050 , the very though of those two reversing  contra rotating at a combined speed of + 6K rpm give me the willies

have run the lathe all morning at near on fully speed and all remains ok back end has the chill off and the bronze one is at its normal comfy hand on  if anyone is interested   lathe bed is at 15 deg c back end is at 18 deg c and the front one is at 30 deg c  which is norma for me

the main difference with the shims in the  AC bearings (inner ) is that the front bearing adjustment was more positive and therefor more controlled so all in all a good job or as the used to say on Scrap Heap Challenge  the Uk version  " its a proper job " until he messed with the governor on a Rolls Royce diesel engine whilst it was running, you can guess the result run away engine that ran on its sump oil


Stuart

[Graham Meek]

Hi Stuart,

Thank you for the photographs you made a very nice job of that. It is nice to notice close up that the plastic gears show hardly any signs of wear.

My best regards
Gray.

[Stuart]

Thanks Gray for your comments

its done a bit of work not a megga amount

the gears are Oilon as its name suggests its a oil loaded nylon, yes I am pleased that its holding up

for info
http://www.directplasticsonline.co.uk/OilonRod

Stuart

[Jo]

For the members who may not have seen this clutch any chance of providing a link to where they can read about it?

Jo

[Stuart]

now Jo that is a difficult one

its detailed in the book by none other but Graham Meek
http://www.teepublishing.co.uk/books/in-your-workshop/projects-for-your-workshop/

more info here
http://www.model-engineer.co.uk/forums/postings.asp?th=49358


but as its copyright to Gray I cannot post any details

but I am sure that Gray will be able to sort something out

the one in the book is for the standard S7 and contains the drawings but the one shown is for the big bore for which I approached Gray and I measured up my lathe and Gray did the drawings then between us we sorted out a small niggle and the result is as shown

for those that do not know what a dog clutch does it is a device that is fitted to the very very expensive lathes ( megga Wonga ) and allows screw cutting up to a shoulder at speed with the trip bar stopping the leadsrew.

also the most important on a myford with its english leadscrew it will when fitted with a 34 t output gear allows metric threads to be cut on a lathe with a norton box , but as you well know you have to wind back the whole lathe with the leadscrew still engaged.

this device by its nature will only pick up the thread in one spot repeatedly so you set it all up and push the leaver towards the chuck and off we go the unit trip and with the lathe still running withdraw the tool and push the lever towards the tail stock and the carriage goes that way  . no need for a thread dial at all

but I am sure that Gray will fill in the bits I have left out after all its his design and a great job he did

Stuart

[Graham Meek]

Hi Stuart,

As I have said many times I just did the easy bit, you did all the hard work.

A version of this clutch comes out in the March edition of Engineering in Miniature to fit the Sieg C3 lathe.

Later this year there is a reprint of the Super 7 clutch coming out in Home Shop Machinist, which will be followed by Jim Schroeder's designed version to fit the Grizzly G0602 10X20 lathe.

A version was also worked out for the Warco BH600 lathe thanks to help from Graham Howe and drawings for this version are available at the following link, there is sure to be a Grizzly counterpart.

http://modelengineeringwebsite.com/Meek_screwcutting_clutch.html

Clutches have also been designed for the Myford ML7, the Emco Compact 8 and the Wabeco D6000, which is nearing completion. This last version has been a joint venture between Tom Hess and myself.

My best regards
Gray,

[steamer]

Great!

Maybe we can figure a way to get it on my South Bend!....

Dave

[Graham Meek]

Hi Dave,

That is what I have been hoping for, I did start drawing a version out to fit the Boxford but those who offered to help seemed to loose their enthusiasm and alas it has not been completed. Having spent sometime designing the various clutch versions over the past couple of years, my own projects are falling by the wayside so I decided to draw a line under the Wabeco version at the beginning of this year, in the hope that someone would pick-up where I left off.

I will endeavour to assist as best I can to get the Southbend version up and running, my dream lathe has always been a brand new Southbend found still in it's packing crate since the 1930's, well you can always dream.

My best regards
Gray,

[steamer]

Mine is Newly Reminted......

Full bed grind, and a full rescrape, new tailstock, full tooling.    Done and dusted.

Brand New.

Let me know if you need dimensions.    1951 Model A with a 4 1/2' bed.

Dave

[Graham Meek]

Dave,

You lucky man you, and there you go trying to get me to break my New Years Resolution, Oh well go on then.

May I suggest a new thread, (excuse the pun) for the Southbend  Screwcutting clutch? I shall need photographs to start off with to see if it is viable.

My best regards
Gray,

[steamer]

It only took two years to do the rebuild Gray....can't rush these things!

I'll send you some pictures later this evening.

Dave

[Stuart]

Dave

you will enjoy working with Gray on the project

its not true what he said about me doing the hard work I only supplied the requested dims. and built the prototype for the big bore he did the work in the design phase, there was only one errata on Gray 's drawing to do with the over travel stop but that all.

if it needs the ali block like mine it can be done on a manual mill /lathe ,thats how I did mine ( I have no CNC ) , it would be a walk in the park for a CNC mill , the hardest part for me was ensuring that the gear centres were accurate as there is no fudge factor its right or wrong , so you have to be very careful , but once thats over its normal turning

I will say that if the design for the actuator is the same , I guess it will be as its a proven one be careful you do not lose the 1/8 ball in the moving parts the over travel stop prevents this when in use but can happen when you are putting it together.

pat on back to self I did not lose mine but I think  Gray did twice and it took him a fair amount of time to get it out  , but I am sure you will be OK


Stuart

[steamer]

Well....no CNC in my shop either, but I've always been intriqued with Gray's design.    Now that Samantha Bell is done, it sure is something I would like to consider.     

I'm excited!....But Gray.    Seriously.    If you want to take your time, and get some other projects under your belt.   Do so.

Samantha Bell isn't going anywhere anytime soon.

Additionally, what ever design or drawing help you need, let me know....I do that for my day job too.

Dave

[Graham Meek]

Hi Dave,

It's not a problem as regards my other projects, this should only take a couple or so days at the drawing board. To give you some idea of what I need to know as regards the photographs. A front view of the lathe, an end on view of the tumbler reverse including change wheel quadrant, a side on view of the tumbler cluster from the front in line with the back face of the headstock casting, an above view of the cluster from this last viewing point taken at about 1 o'clock. Finally a view down the rear of the bed from the headstock and tailstock ends. That should do for now as regards pictures, but I will need to know the DP & PA of the gears, the number of teeth on the Mandrel gear as well as the numbers of teeth in the tumbler reverse and very important which position the tumbler reverse is in when turning towards the headstock.

My best regards
Gray,

[steamer]

Thanks Graham!

18 DP   14 1/2 PA

Spindle gear is 24 tooth.

I'll get the rest.

Dave

[ths]

Hi Gray,

Has the version for the ML7 been made available anywhere?

Cheers, Hugh.

[Stuart]

Not sure Gray would have to answere that question

Stuart

[Graham Meek]

The position on the ML7 is as follows, the prototype for this machine has been made and fitted to the donor lathe, which is about 150 miles away from me. Apart from a slight fouling problem with a sheet metal guard the parts fitted and worked as planned. The only thing outstanding at this stage was the routing of the trip rod, I had a rough idea of where it was going to go but you cannot beat having the hardware to actually see this. The trip rod exits from by the headstock casting but has to drop and move away from the lathe to follow the S7 routing, I have designed a bracket to do this. I am still waiting to hear about the final outcome, but in the meantime I have had several people contact me for drawings. I have explained to them the above situation and they have proceeded to make their versions with a little help from me.

Under normal circumstances I would let my drawings go out on the sole understanding that it was for the users eyes only and without charge. I found out yesterday that someone has betrayed this trust as drawings for my Sieg version of the clutch have turned up in the Sieg factory. A classic example of how one persons greed spoils it for all the rest.

If prospective builders of the ML7 version would like to send me an email I will endeavour to help as best I can.

My best regards
Gray,

[steamer]

I am very sorry to hear that Gray.   However, I would doubt  they will go forward building this clutch on a lathe with such a low price point....I would think they would be better off spending the money on better BASIC features on the Seig lathes.   Like power cross feed for instance or a better tailstock/tailstock base, ect.

In any case, post what you're comfortable with, we understand, and as always, you retain all rights to the work published here.

Dave

[Graham Meek]

Hi Dave,

The people concerned are known and they intend marketing a kit for the attachment.

My best regards
Gray,

[ths]

Hi Gray,

PM sent.

Hugh.

[Graham Meek]

Hi Hugh,

I have relied to your PM and you might also like to see the latest posting on the ME forum by Jim Shroeder,

http://www.model-engineer.co.uk/forums/postings.asp?th=49358&p=19

My best regards
Gray,

[ths]

Hi Gray,

I have responded to the email address you supplied.

Many thanks,

Hugh.