125mm HBM Chuck too heavy for Myford ML7???

[ross748Participant @ross748]

Thank you for the welcome, and thank you for all the responses.

The HBM chuck in question is as per the link posted by MichaelG but obviously with the appropriate back plate for the Myford threaded spindle (it actually came ready to screw onto the spindle right out of the box).

My lathe is still running on the original white metal bearings and the max spindle speed is only ~600 rpm (I think from memory). I keep the drip oilers topped up with hydraulic jack oil which I was reliably informed is a good subsitute for the original grade of oil?

The general consensus seems to be that the spindle bearings will cope with a chuck of this weight so I will carry on using it and try not to be so mechanically sympathetic in the future!

I'd still be interested to know why Myford have the strong warning about the weight of the 125 mm PB chuck (I did send them an e-mail but I never got a response).

Thanks again – Ross

[KWILParticipant @kwil]

Myford and RDG are of course 2 separate legal entities, RDG does not own Myford.

[bodgeParticipant @bodge]

"Oh dear its a bit big" It just looked wrong.

Thats about how i see it , i saw myford m type years ago with a polish 5 inch on it, didnt look right at all ! Read an article in a old m e on this subject, as a rule of thumb dia of 3 jaw chuck to be about same width as the lathe shears. Its not helped by the fact that there is usually not much in it price wise between a 4" & 5", it is tempting to go for the 5"….Anyway while i was uming & ahing and the price is going up ! ..had a look on ebay found 4/1/2 Vertex so went with that , 25% cheaper looks ok and quality is on a par with the polish chucks, the vendor was rdg ebay shop…. Hard to believe 1/2 inch on size of a chuck makes that much difference, but it does !!

bodge.

[LambtonParticipant @lambton]

KWIL,

A quick on-line search confirms that RDG and Myford both have the same Directors and the same address as their registered office. Nothing at all wrong with this of course. True they are two separate legal entities again absolutely nothing wrong with this but obviously which ever entity is being dealt with the people running it are the same.

I have dealt with both and have no cause for complaint.

[KWILParticipant @kwil]

Lampton, totally agree, both Richard and Alan are great guys.

[AjohnwParticipant @ajohnw51620]

Posted by bodge on 07/10/2015 14:40:54:

"Oh dear its a bit big" It just looked wrong.

Thats about how i see it , i saw myford m type years ago with a polish 5 inch on it, didnt look right at all ! Read an article in a old m e on this subject, as a rule of thumb dia of 3 jaw chuck to be about same width as the lathe shears. Its not helped by the fact that there is usually not much in it price wise between a 4" & 5", it is tempting to go for the 5"….Anyway while i was uming & ahing and the price is going up ! ..had a look on ebay found 4/1/2 Vertex so went with that , 25% cheaper looks ok and quality is on a par with the polish chucks, the vendor was rdg ebay shop…. Hard to believe 1/2 inch on size of a chuck makes that much difference, but it does !!

bodge.

What really matters is the diameter of the work to the width of the shears. Some bed designs can cope with a lot bigger ratio in that area than others.

John

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[Mike PooleParticipant @mikepoole82104]

I have a 5" for my 7R but I only use it when it is needed as it makes some tasks a bit easier, everyday wear is the classic 4". I find the 5" requires extra awareness of the jaw cross slide clearance particularly with jaws extended out of the body. I agree it makes the Myford look over chucked but it can be useful and the 6" 4 jaw could probably do anything the 5"SC could do.

Mike

[MalcBParticipant @malcb52554]

Posted by Neil Wyatt on 07/10/2015 12:36:25:

Opps, of course ML7s have plain white metal bearings. Babbit has a max pressure of 800-1500 psi (according to my Machinery's), it doesn't give pv values for babbits (although it does for wood, teflon etc.!)

The net suggests pv values from 12,000 to 30,000, still plenty high enough that chuck weight shouldn't be an issue, especiually as you will be using lower speeds with such a big chuck (I hope).

Neil

It is highly unlikely you will ever find a PV value for white metals. PV values are calculated in a dry condition twixt bearing material/support like plastic bearings and the shaft or collar ( sliding or rotating ).

White metal bearings are designed to operate as fluid film bearings. The lube can vary from mediums such as water, oils, chemicals, greases etc.

It would be nearly impossible to get/calculate a PV value that meant anything as every medium would have to be used and their would be thousands, literally and also for each type of white metal alloy.

Neil is right in that it is very important to ensure you maintain that fluid film in any white metal bearing application. Loose that and you will get premature bearing failure.

Hence the key will be keep your bearings clean and well lubrcated and protect as much from foreign bodies.

[Neil WyattModerator @neilwyatt]

Posted by Lambton on 07/10/2015 14:11:19:

"No, Myford still make lathes in the UK"

Neil, this is news to me as I did not think that New Myford (AKA RDG) actually made anything. They maybe assembling some items from parts obtained when they took over Myford. Perhaps they could let us know.

Well that quote I gave is direct from their website…

I'm sure Alan told me they are now making Connoisseurs from the ground up, but I may be mis-remembering. Certainly he said that they have re-introduced some old accessories and added some new ones (e.g. tailstock drilling attachment) that are UK made.

Neil

 

Edited By Neil Wyatt on 07/10/2015 19:56:42

[Mike PooleParticipant @mikepoole82104]

I was at a show and Myford confirmed that the lathe I was looking at was made in the UK it looked very nice and a worthy successor to the Nottingham machines. Price is the only downside. A lot of work must have gone into getting the Myford back on sale and I hope some people will choose to afford one. I feel Myford are not blowing their own trumpet enough at getting the lathes manufactured again as the beliefs of some people on this forum show the word has not got out too well.

Mike

[MalcBParticipant @malcb52554]

One of our daughters lives in Mytholmroyd where they are both located.

Their main premises are located nearby and are adjacent to each other so I have visited both a few times.

RDG is definitely a box shipping operation for overseas procured items. Really impressed with some of their stuff myself considering and I have one of their HBM 125mm self entering 4 jaw chucks on my Boxford and T1 quick change toolpost said. Accuracy and repeatability in my opinion is really good on the HBM.

From what I could see of the Myford operation is that they appear to be doing it all.

Building machines for sale.

Importing machines for sale.

Rebuilding and refurbishing machines for sale.

Buying in parts for resale.

Buying in parts for their builds and refurbishes.

They also have another industrial unit nearby to the showroom and workshop, so do not know the extent of their in-house actual manufacturing.

When you look at the standard and engineering quality of their machines it is to a very high standard of finish in comparison to Warco, Chester, Axminister etc ( my opinion only ).

However where they get £9k from for a Myford lathe without readout or CNC input is beyond me when you can get a quality conventional high rebuild standard Hardinge toolroom lathe for less.

[bodgeParticipant @bodge]

Mike

That"s about how i see it too, my problem was i never had any reverse jaws, as is often the case with older s/h lathes. Out of 4 lathes & 5 three jaw chucks, not a reverse jaw to be seen not even an odd single jaw , and out the five only two any good, and they are the everyday 4 inch ones and the vertex 112mm is ready to go with out side jaws fitted, just that bit more capacity is very handy and its quicker than swapping the jaws.I would not have thought the weight involved would be a problem as a six inch four jaw independent is usually the norm for myfords plus whatever is gripped is going to weigh a bit anyway. I have seen a five inch on ML 7R [at least i think it was an ml7R] looks about as much chuck as it will stand, on my mangle a five inch looks silly[one of the duff chucks was a five inch] but the four an half inch is about as much as it will stand

John W1

Read an article in a old ME on this subject, as a rule of thumb dia of three jaw chuck to be about the same width as the lathe shears.This was the answer given on the readers question page back in the days of snail mail, and technical questions were answered by the likes of Proff Chaddock,GHT,and others. pity there not still around for,you to take it up with.

bodge.

[Ian S CParticipant @iansc]

The important bit about weight is, how far from the front bearing is the weight, a thick chuck on a back plate will load the bearing, this is relieved when work in the chuck is supported by the tail stock centre.

Ian SC

[JonParticipant @jon]

With an ML7 white metal tinned bearings used to use supplied 4" and 6" Pratt and Burnerd mentioned above. wore the 4" out and replaced on separate thick backing plate a Bison 5 1/4" I now use on the rotary table.
Used to run it estimated 900 to 1000rpm with 1hp Brooke Compton motor and self made phosphor bronze bearing halves scraped in, what a pain. Had about 20mins heavy duty work, by normal means ie within constraints would have taken no joke 4hrs.

Scrapped it after 7 years in 1999 nothing any good except Dewhurst start switch and stand.

[AjohnwParticipant @ajohnw51620]

I'd gladly take it up with him Bodge. I'm sure he would agree that the main factor is the diameter of the work. It all down to the angle of the forces down on to the bed and that needs some consideration of the design of the bed and how the saddle is anchored to it as well.

Take my Boxford. That's about 130mm peak to peak across the shears. A 200mm 4 jaw is normally fitted to it. That means that at the limit the downward forces would be outside of the shears so the saddle would literally tip. To prevent that they hook the the back of the saddle to the underside of the rear rail – just like they do on most small lathes. When the work is 130mm dia the tool and etc is outside of the shears as far as the loading is concerned. I posted a shot of a Wabeco 4000E in Brian's lathe problem thread which show the problem rather well. I don't intend to make anything that big on it so the other aspects aren't much of a worry. It's just that what they have done is stupid and in some respects spoils the lathe. It's even possible to move the compound slide further out where it would be able to turn it's full 220mm swing over the bed.

John

-.

[bodgeParticipant @bodge]

John,

The OP was about a 3 jaw chuck on ML7, Not about a four jaw ind or a well loaded face plate, more to do with over hang and the increase in weight, now i could be wrong but i have the idea that an original ml7 is about four inch across the shears with white metal bearings. So in my totally worthless opinion i think as a general rule the diameter of chuck to be about the same as width of shears holds good as it deals with both aspects ,over hang and mass, also if using the out side jaws at their maximum this would put the forces out side of the shears anyway even with a 4" chuck, more so with a 5" thats assuming the protruding jaws dont clout the bed first, then there is the how much diameter can you get over the cross slide, on a lathe with 31/2" centre height , minus cross slide height = 4" dia maybe, and if one was to be turning a lot of stuff at that sort of size maybe one should have bought a bigger lathe. At the end of the day it seems like price paid for said chuck was the main factor

This is the same problem ? that Neil , Rod, & co are having with the Adepts & Flexispeeds, just smaller.

As far as downward force being out side of the shears, with a gap bed it"s going to happen , there was a article in ME pretty sure it was by Martin Cleeve in it he describes how he managed to bust the cross slide on a ML7. my old mangle will take 11 inch dia in the gap but its only 4 inch across the shears and i have had it up to the limit, with a fly wheel, had about 30 thou clearance in the gap, the cross slide travel on the mangle is five & a half inch, cross slide is 11 inch long plus another 2 1/2 inch on the stand off bracket ,so it will reach , much caution required !! So yes i am well aware of forces out side of the shears, Every once in awhile i kick the idea around of adding a 3rd shear, due to the bed lay out it would be a fairly easy mod.

Yes i did take a look at your 4000E thats the kind of photo one wishes they would put in the sales blurb, it is always interesting to see the finer points of different machines, brief road test report would be nice when you have had a fair go with it ?

bodge

[ross748Participant @ross748]

I still have the original Pratt Burnerd 4" 3-jaw (completely worn out) and 6" 4-jaw chucks that must have been supplied with the lathe. Interestingly they weight almost exactly the same at just a shade over 4 kg. I also have a very old 5" Taylor tapered scroll 3-jaw chuck that came with the lathe and that weighs just over 5kg, however i've never used this chuck in anger.

I purchased the larger 125mm HBM chuck (there is a 100mm version) to replace the worn out 4" original. I decided to go with this particular manufacturer based on its cost and quality both being acceptable and also becasue it has a larger hole through the middle meaning I wouldn't be left with so many stubs of material.

I only use my lathe for small jobs as I have access to a Colchester student and a Boxford Industrial lathe at work.

Just to confirm – on the ML7 the distance accross the shears is 4.5" and the max swing radius is 3.5".

I'm still a bit concerned that the HBM chuck weighs 1.5kg more than the original chucks, but I guess the maximum speed i'll be using is ~600 rpm and as long as I don't load the chuck up with anything too heavy it should be okay.

[Martin KyteParticipant @martinkyte99762]

Whilst I would concur with much of the comments on shear dimension etc

The Myford site says

THIS 125mm CHUCK IS TOO HEAVY TO MOUNT ON ANY MYFORD WITHOUT THE M42.5 x 2mm 4MT SPINDLE

As far as I am aware the shears on the big bore Connoisseur lathe are no bigger than the small bore Super7. (I am happy to hear if someone knows different). The warning seems more concerned with the slenderness of the spindle. The big bore is going to be a lot stiffer than the much lighter small bore spindle.

I too purchased a 125mm 3 jaw and a 125mm self centering 4 jaw from Myford about 4 years back so I am intrigued to know just what the thinking behind the warning is. I have to admit to removing the 125 from the lathe when not really required and using the 100mm or ER collets for general use until I know more.

It really could be anything, even that maybe the risk of damage to the spindle nose is that much greater when attaching or removing the chuck from the small bore spindle to bearing overload to twist or whip of the spindle itself when running up.

What we really need is to ask Myford why they issued the notice. They will be at the Midlands show so a direct question seems to be in order.

regards Martin

[AjohnwParticipant @ajohnw51620]

As they supply a bigger 4 jaw the comment doesn't make much sense really. I only mentioned Boxford because it's right by me so I could measure it. I just don't believe an extra kilo or so would make any difference. I could understand why people wont do what I am about to do fit a 200mm 3 jaw. The weight difference in that case is very large. I'm doing it to obtain a bigger hole in the chuck not to hold bigger work,

Noticing another comment, chucks shouldn't be used with the jaws sticking out really and I'd guess some people do take a bit more care if they have to use them like that. To far out and the scroll and teeth on the back of the jaws wont all be meshed and there is far more chance of striping the scroll.

I can't weight to hear the answer.

John

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[ross748Participant @ross748]

I totally agree, I did send Myford an e-mail about this but never got a response.

I also contacted RDG who did get back to me and they stated that the 125mm HBM chuck is lighter than the Pratt Burnerd chuck sold by Myford and is therefore suitable for use on the ML7. However, we have a 125mm Pratt Burnerd chuck at work so i've weighed both chucks and the HBM chuck is actually slightly heavier – so even more reason to be concerned about the warning from Myford!

I also remove the chuck when its not in use as it just feels to heavy for the size of the spindle.

[John Stevenson 1Participant @johnstevenson1]

Posted by John W1 on 07/10/2015 13:39:02:

As to the rest well I feel that in respect to this thread bullshit baffles brains. It often does.

John

–

Could not agree more………………………….

[Michael GilliganParticipant @michaelgilligan61133]

No one yet seems to have asked the obvious, and pertinent, question:

Does anyone have a Lathe Handbook produced by the current Myford company ? … and does it include any reference to a maximum 'nose weight' ?

… It is just plausible that there is a 'Type Approval' issue.

MichaelG.

[Mike PooleParticipant @mikepoole82104]

As I mentioned earlier I usually have a 4" threaded body PB mounted and the distance from the register face to front of jaw is about 73mm, the 5" TOS is 105mm, this is quite a lot of overhang on a small spindle and is the factor that concerns me more than weight. As a significant amount of work done in a homeworkshop is too big for the machines it is a tribute to all makes that it takes it in its stride, of course material removal rates usually match the precariousness of the setup but with care and sympathy for the abuse no harm is usually done. Some chucks I have are marked on the jaws to indicate the maximum allowed extension from the body but jaws sticking out are another danger as I often use my hand on the chuck as a brake (probably bad practice) and doing this with jaws sticking out will propably result in the red stuff leaking out.

Mike

[bodgeParticipant @bodge]

I cant weight to hear the answer.

John you have had it already, in big red letters, the post above yours.

At the end of the day i dont see it matters much 4" or 5" there are folk reading this using either

As for jaw projection if you take a look at Brians pics with his on going saga with the little TU one shows a chucked fly wheel and the jaws are sticking out past chuck dia, it"s the one with the threading tool being used on the rim……..Nuff said at least by me on this topic. it"s getting to be a bit like how longs a piece of string

bodge.

[ross748Participant @ross748]

Apologies if my original posting has generated such a drawn out debate.

Just to re-focus this thread – my concern was specifically about using a 125mm chuck that is ~25% heavier than what was supplied with the lathe, and that concern was reinforced by what I found on the Myford website:

THIS 125mm CHUCK IS TOO HEAVY TO MOUNT ON ANY MYFORD WITHOUT THE M42.5 x 2mm 4MT SPINDLE

This statement is specifically referring to the weight of the chuck and the size of the spindle, I’m not sure where the "bullshit baffles brains" mentality comes in here, the engineers at Myford must have carried out the relevant spindle/bearing load calculations and identified a potential problem.

In reality I don't suppose there are any safety concerns to worry about and nothing is going to break if you use the bigger chuck. If the lathe is worked hard with the bigger chuck I guess you may suffer accelerated spindle bearing wear and perhaps the rigidity of the lathe is not quite up to the size of the work you could potentially clamp with the bigger chuck. Who knows, let’s wait to see what Myford have to say about it.

The fact that the 125mm chuck is physically bigger is not really of concern because as practical, mechanically minded engineers, I’m sure we would all use our common sense and machining skills not to try and hold something too heavy or too big for the chuck (and that goes for any size of chuck!!).

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