Is this normal in backing plates

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.

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

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

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

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.

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

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"

Some never learn!

That should give you a much nicer fit than the old Myford carrot in a shirtsleeve job.

Once you get up and running a bit you may be able to salvage the old Myford back plate by clamping it to a faceplate (or another backing plate) and boring it out and screwcutting it to accept a threaded sleeve that you could then bore to final size and screwcut to fit your lathe spindle correctly. Loctite the sleeve into the backing plate and it should work ok. Cast iron is quite nice to screwcut. Gives a nice finish usually.

In agreement with a post made recently, I'm sure John Stevenson would advise the OP to take up knitting. In the past I've advised people who seem to be pretty clueless to take up baking or gardening, only to be berated for it and to receive PM's stating ' it's only a hobby lol' . Puts me in mind of the kind of giggling childish adults posting Darwinian crass stupidity on YouTube, due to them having little knowledge or understanding of much at all.

Be safe and don't kill yourselves with things you know precious little about, otherwise the H&S Gestapo will be down on us all. Pressure vessel testing for club run equipment I fully agree with. Telling me that I can no longer run my surface grinder, bandsaw, t&c grinders, millers, lathes and drilling machines at home because we have potential clients for the idiocracy in our midst I certainly don't want.

L O L .!

Knitting is a bit too dangerous with those two pointed needles, tatting might be safer.

Ian S C

In fact, the chap JS suggested take up knitting went on to make a good number of very well-built model engines, both steam and flame-lickers, all done on a rather sub-par low-cost micro-lathe. We all have to begin somewhere.

Now you will be faced with the dilemma of is a 5" chuck too heavy for a Myford which was recently discussed

Lol, it’s only a hobby, why on Earth worry over it.

A 7’’ may well fit, too! Might not be able to wind it out too far, mind

You'd worry if an improperly matched and fitted chuck came off and hit you in the face 

Edited By David Standing 1 on 13/05/2018 13:59:07

My thoughts exactly David, seems that some don’t get the picture though🤣

On a slightly different tack, since it was mentioned, Don't rely on a water based cutting fluid not causing rust because it has an inhibitor. An inhibitor is not a preventer so splashed need sorting out immediately. Although some amateurs do use flood cooling occasionally mostly it is not necessary and only used to wash away bulk chips with a bigger lathe. Often a small brush putting on a little neat oil is best.

Obey the caution of others about mounting too large a chuck onto a small lathe.

You have been lucky once. You can do without wrecking the Headstock bearings by overloading them.

Despite the LOLs, if you don't do the job properly, using measuring equipment where needed, the least that you will do is waste time and material, at worst, injure yourself, or someone else.

You are dealing with a machine, which although maybe only quarter horsepower, is more powerful than you (about 300 Watts!) and does not feel pain, or have the common sense to stop when something goes wrong.

A hobby that causes injury to you, anyone else, or your investment, is not one that you should pursue.

Be sensible and take care!

Howard