Is this normal in backing plates

[SamsarandaParticipant @samsaranda]

Checked College Engineering website this morning and they still list their range of backplate castings as available.

Dave W

[Jon GibbsParticipant @jongibbs59756]

If you're really after an unmachined cast backplate then Chronos have them here (P&P included)… **LINK**

[Martin NewboldParticipant @martinnewbold]

Hi everyone . Thank you for the comments

I think the ML7 must be 1" x10tpi . Am pretty sure that mine must be 1" x 8TPI. I might buy a RDB one to see if it fits better which is 1 " x 8TPI. I am hoping they are all not rubbish cast iron I have to confess the one i bought it didn't screw right on as far as my original chuck I am guessing the thread differences was the problem Live and learn ML7 is not Drummond

Am sure this might sort it out. Have been busy with other bits with my chinese pump and cutting liquid conversion so haven't had time to get one yet have been in correspondence on eBay RDG to check the cast iron is not cheap rustable version with steel in it. but will wait till i find out.

All the Best

[Martin NewboldParticipant @martinnewbold]

Posted by Hopper on 02/05/2018 12:19:29:

Posted by JasonB on 02/05/2018 12:02:49:

Could this be the adaptor

That's an odd one. I thought Drummond M Type was 1" x 8tpi, not 12tpi as the ad in the link says. Either way, lot of extra overhang there. I think a proper Drummond backplate from lathes.co.uk would work better.

OMG dont but one I bought one from Myford it was dreadful didnt fit properly at all was as bad as the ML7 backplate fitting it could be it was wrong TPI . Myford said they had lots of probs its possible its not as listed but clue less here and refunded great company.

[Tim StevensParticipant @timstevens64731]

Martin

You need to be aware that the ML7 chuck thread is 1 1/8" and 12 threads to the inch. This is not something I think is correct, I know it and I have checked it by measurement. It is not difficult to check the diameter and the pitch, and anyone who tries to fit a chuck by guesswork rather than measurement is likely to have problems. If you do not have a thread gauge, get one.

And do us all a favour, please. Next time you have a problem, TELL US what the problem is about. Your message implied that it 'just broke' when you now say that your chuck never fitted properly in the first place. So, we suggested all sorts of likely causes, and some unlikely ones, when you knew what the problem was likely to be, and it was not a problem with the chuck itself, most likely, but the fact that it did not match the lathe it was fitted to.

I'm sorry I wasted my time. I'm sorry you wasted my time. Don't do it again. Most of us have little enough of it left.

Tim

[Martin NewboldParticipant @martinnewbold]

Hihi Hopper

Over powered no way . It just sufficient . Have an inverter fitted so am running at approx half power . Am very pleased with the drive the new gearbox i built is excellent and do not think this is causing any problem.

The back plate was not fitting as well as i hoped but did some work in brass before without failure. It has been somewhat modified yes but stock spindle is same as original i think . I was not taking to much off to allow the tool to dig . My belt would slip before any damage was incurred through a tool dig even though there was not one.

I am going to get a 1" 8TPI backplate and try that from RDG if they come back with some information

Posted by Michael Gilligan on 02/05/2018 09:59:16:

Posted by Hopper on 02/05/2018 09:16:43:

No I havn't been following the whole saga closely enough to remember every detail. Do the modificationss include a larger spindle thread to match an ML7 backplate?

I would expect the belts to slip or the tool bit to snap off long before a lathe tore the chuck off the spindle if the threads were properly made and engaged.

If Martin could clarify …

.

No modified spindle thread, so far as I am aware

MichaelG.

[Martin NewboldParticipant @martinnewbold]

Tim,

I think your right . I bought the back plate not with the chuck am still learning about this threads as they are very hard to know the difference by eye and all look similar.

I found a tale piece for drummond b and its listed as 1" x 8tpi.

All the best

M

Posted by Tim Stevens on 03/05/2018 20:14:11:

Martin

You need to be aware that the ML7 chuck thread is 1 1/8" and 12 threads to the inch. This is not something I think is correct, I know it and I have checked it by measurement. It is not difficult to check the diameter and the pitch, and anyone who tries to fit a chuck by guesswork rather than measurement is likely to have problems. If you do not have a thread gauge, get one.

And do us all a favour, please. Next time you have a problem, TELL US what the problem is about. Your message implied that it 'just broke' when you now say that your chuck never fitted properly in the first place. So, we suggested all sorts of likely causes, and some unlikely ones, when you knew what the problem was likely to be, and it was not a problem with the chuck itself, most likely, but the fact that it did not match the lathe it was fitted to.

I'm sorry I wasted my time. I'm sorry you wasted my time. Don't do it again. Most of us have little enough of it left.

Tim

[Martin NewboldParticipant @martinnewbold]

Hi everyone By the way i do have another 80mm back plate marked up v1012 but cant find out who made this or what threads are in it i measured the thread part which is 1/2" and 5 threads there in with the blank unthreaded section 1" dia  would this infer it is 1" x TPI 10?

 

M

Edited By Martin Newbold on 03/05/2018 20:37:51

[Neil WyattModerator @neilwyatt]

Can I suggest you take a few measurements of the spindle nose before investing more money?

It isn't hard to measure how many full threads are in an inch, if 8tpi they will be exactly 1/8 of an inch apart.

[JasonBModerator @jasonb]

Martin what is that 10tpi thread gauge photo in your album measuring, looks like your spindle nose to me so why try an 8tpi backplate?

Anyone else think this thread looks a bit long?

Edited By JasonB on 03/05/2018 20:35:15

Edited By JasonB on 03/05/2018 20:36:22

[Tim StevensParticipant @timstevens64731]

Yes, threads are not always easy to check by eye. You need to get to grips with this, though, as you will come across threads which all look like 8mm or 5/16" diameter, and might have 40, 36, 25.4, 24, 22, 20.32, or 18 tpi, and that is just the common ones.

And I forgot 26 as well.

Tim

Edited By Tim Stevens on 03/05/2018 20:42:21

[Martin NewboldParticipant @martinnewbold]

Well i just tried measuring my other plate and it would concur that its 1" x 10TPI

Posted by Martin Newbold on 03/05/2018 20:25:11:

Hi everyone By the way i do have another 80mm back plate marked up v1012 but cant find out who made this or what threads are in it i measured the thread part which is 1/2" and 5 threads there in with the blank unthreaded section 1" dia would this infer it is 1" x TPI 10?

M

Edited By Martin Newbold on 03/05/2018 20:37:51

[Martin NewboldParticipant @martinnewbold]

If the gauge is correct Jason then It cannot be a Drummond B, lol. It was much modified before i got it . If ML7 is 8TPI it would explain a lot why this failed.

All the best

M

 

Posted by JasonB on 03/05/2018 20:33:18:

Martin what is that 10tpi thread gauge photo in your album measuring, looks like your spindle nose to me so why try an 8tpi backplate?

Anyone else think this thread looks a bit long?

Edited By JasonB on 03/05/2018 20:35:15

Edited By JasonB on 03/05/2018 20:36:22

 

Edited By Martin Newbold on 03/05/2018 20:47:16

[JasonBModerator @jasonb]

Well the gauge looks like it fits correctly so you have a 10tpi spindle nose.

[FarmboyParticipant @farmboy]

Posted by Martin Newbold on 03/05/2018 20:25:11:

Hi everyone By the way i do have another 80mm back plate marked up v1012 but cant find out who made this or what threads are in it i measured the thread part which is 1/2" and 5 threads there in with the blank unthreaded section 1" dia would this infer it is 1" x TPI 10?

M

Edited By Martin Newbold on 03/05/2018 20:37:51

If you have an 80mm backplate with a 1" x 10TPI internal thread it should be a perfect fit on the spindle nose in the photo, which appears to be 1" BSF. However, if the thread in the backplate is only 1/2" deep it will not screw fully on to the spindle

If the damaged backplate was either 8 or 12 TPI that would explain the stripped threads . . . I would just be grateful that the spindle thread seems to be still intact!

[John HaineParticipant @johnhaine32865]

Regarding castings and CES: yes they are shown on the website, but no they do not supply at least the backplate castings. As all the price information has disappeared for castings on the site I suppose they have decided only to sell materials now. I confirmed they do not have the casting by email. Its Chronos or RDG.

[HopperParticipant @hopper]

Posted by Martin Newbold on 03/05/2018 20:46:46:

. If ML7 is 8TPI it would explain a lot why this failed.

Not only that, but the ML7 spindle thread is 1-1/8" major diameter and yours apparently is 1". How it even held together for as long as it did is a minor miracle.

[SamsarandaParticipant @samsaranda]

The possible consequences of such a mismatch of threads rotating at a high speed don’t bear thinking about, I think you were extremely lucky to avoid serious injury.

Dave W

[Howard LewisParticipant @howardlewis46836]

Now that the cause of the problem seems to have been found, DO take the advice to buy Thread Gauges. Since you are likely to come across variety of thread forms, ( Whit, Unified and Metric) and pitches DO buy all three.

A steel rule with Imperial and Metric graduations is a good rough starting point ( But 10,12,18 or 28 tpi may not match the graduations on the rule – hence the need for gauges.

Whit form will cover 55 degree thread forms, such as BSW, BSF BSP (Gas), B S Brass, and Model Engineer 32 and 40 tpi. Unified will cover 60 degree Unified and Cycle thread form, but NOT Metric.

Metric threads are also 60 degree, but the pitches will be Metric not Imperial.

If you are likely to get involved in older electrical items, you might find BA useful, since the thread form is 47.5 degrees, but the diameters and pitches are metric, each changing by a factor of 0.9.

You are less likely to get involved with Acme or Buttress threads, so wait until you need gauges for those.

Once you know exactly what a thread is, form, pitch (or tpi) and diameter; you can obtain or make a correctly mating part.

If you don't know, you are working blindfold, and will waste at least a lot of time, if not money and material.

Howard

[Martin NewboldParticipant @martinnewbold]

Lol , Howard this is just a hobby

I was lucky enough to buy a 1" 10tpi 5" backplate and its a sweet fit like my other badly interfaced chuck which is 4.5" So am now looking for a sweet 5" bernard or pratt chuck that bolts right through. I did buy one but hermes messed up delivery and never got it as the seller got cross as hermes made no attempt to deliver at all . I must add of late Hermes have gotten better..

MY pum p is working well and can spray cutting fluid everywhere and redecorate my tools luckily i understand it has an anti rust agent in it Its not only white at christmas lol

Martin

Edited By Martin Newbold on 12/05/2018 11:38:05

[Ian HewsonParticipant @ianhewson99641]

A hobby that can kill you if you are careless about what you are doing. LOL

[Nick Taylor 2Participant @nicktaylor2]

Posted by Ian Hewson on 12/05/2018 14:01:18:

A hobby that can kill you if you are careless about what you are doing. LOL

Indeed. The OP has been incredibly lucky, and had he not been so fortunate the only person to blame would of been himself.

[Anonymous]

Posted by Nick Taylor 2 on 12/05/2018 14:36:50:

Indeed. The OP has been incredibly lucky, and had he not been so fortunate the only person to blame would of been himself.

Had he done so I'd have been looking out for the posthumous winner of the Darwin award. But more seriously if he'd managed to hurt, or worse, somebody else then that would reflect badly on us all and increase the chances of official interference.

I wonder if the late, great, JohnS would have advised him to take up knitting?

Andrew

[Martin NewboldParticipant @martinnewbold]

Haha Andrew its nice to be lucky once lol it doesnt occur very often . This is a great find am not going to cut it down but find a bigger chuck to fit it as its 5" and my bigest is 4.5"

[Ian HewsonParticipant @ianhewson99641]

Some never learn!

[Author]

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