Leadscrew Handwheel Bore?

[kevian64Participant @kevian64]

I’d like to get a Leadscrew Handwheel for my ML7 Trileva but having seen several for sale on Ebay, by RDG and Myford Ltd there are 2 Bore sizes 7/16 and 1/2″. How do I know which one I need please?

Thank you

[Clive FosterParticipant @clivefoster55965]

Best to pull the spacer off and measure the diameter of the extension at the end of your screw.

For older machines it’s never completely safe to assume that things are still as per factory specification.

Clive

[kevian64Participant @kevian64]

I’m more used to metric as opposed to imperial, if I do buy a leadscrew handwheel with measurements, is it just a simple matter of buying a metric scale wheel or do the maths not add as my lathe is imperial?

[Clive FosterParticipant @clivefoster55965]

So far as I’m aware all Myford ML 7 machines, both metric and imperial, used an 8 TPI lead screw.

So the hand wheel will have 125 graduations each corresponding to 1 thousandth of an inch movement of the saddle along the bed when being driven by the handle.

Clive

[Clive Foster]

On Clive Foster Said:

So far as I’m aware all Myford ML 7 machines, both metric and imperial, used an 8 TPI lead screw.

So the hand wheel will have 125 graduations each corresponding to 1 thousandth of an inch movement of the saddle along the bed when being driven by the handle.

Clive

Ahhh, yes, I’ve seen the imperial wheels with 125 graduations and the metric goes to 3.0mm so I’m guessing 125/1000 = 3.0mm?

[bernard towersParticipant @bernardtowers37738]

If the wheels for sale are non genuine the scale is pressed on, could you take off and fit recalibrated version. I bought one a few years ago and remachined the inside and and refitted with a wire spring to make it a resettable, that might be possible.

[roy entwistleParticipant @royentwistle24699]

Orignal poster asked for size of bore. I’m going to sugggest 7/16″ I think only the Super 7 had 1/2″

Roy

[bernard towersParticipant @bernardtowers37738]

does it depend on whether the lead screw is 5/8 or 3/4 dia???

[halfnutParticipant @halfnut]

Safest way is to measure your existing handwheel or the spigot it fits on.

[halfnut]

 

On halfnut Said:

Safest way is to measure your existing handwheel or the spigot it fits on.

I’ve not got a handwheel at the mo, hence wondering what size

[Howard LewisParticipant @howardlewis46836]

Being a Myford, the Leadscrew will be Imperial, as will all the other dimensions and threads, so don’t waste time measuring in Metric.

On a wheel with 125 graduations, each division will represent 0.001″ on the 8 tpi Leadscrew, so if you MUST use Metric, each division represents 0.0254 mm.

But why make life complicated?

In UK we measure fuel consumption in Miles per gallon, not litres per 100 Km

Just use Imperial

Howard

[kevian64]

On kevian64 Said:

 

On halfnut Said:

Safest way is to measure your existing handwheel or the spigot it fits on.

I’ve not got a handwheel at the mo, hence wondering what size

Measure the end of your leadscrew that fits into the handwheel.

[Howard Lewis]

On Howard Lewis Said:

Being a Myford, the Leadscrew will be Imperial, as will all the other dimensions and threads, so don’t waste time measuring in Metric.

On a wheel with 125 graduations, each division will represent 0.001″ on the 8 tpi Leadscrew, so if you MUST use Metric, each division represents 0.0254 mm.

But why make life complicated?

In UK we measure fuel consumption in Miles per gallon, not litres per 100 Km

Just use Imperial

Howard

I think you’re right, but I think to make my brain work quicker, I’ll get a conversion table printed out and pinned to the wall behind the lathe.

😊

[Clive FosterParticipant @clivefoster55965]

If you have the space the SwissTech metric/imperial chart is excellent. Wipe clean and sensible size print for reading off the wall.

https://www.zoro.co.uk/shop/tools-and-machining/reference-and-data-books/metric-inch-inch-decimal-and-gauge-size-conversion-wall-chart/p/ZT1126130X?srsltid=AfmBOor55njUqYaWLX8rfmooSMOoK5orCCx2uKFORG_xoAPfNFg-RB-5

The three SwissTech Reference handbooks, Fastener Handbook, Engineers Pocketbook and Engineers Reference are also very good and excellent value for money from Zoro. Rather more modern than the old standby Zeus book, now outrageously expensive at over £17 from Zoro, with lots of up to date information on real world standards et al.

SwissTech also do an excellent tapping and clearance drill size chart

https://www.zoro.co.uk/shop/tools-and-machining/reference-and-data-books/tapping-and-clearance-drill-size-chart/p/ZT1126131X?srsltid=AfmBOoogl83O2IopFVEWg148m5GM22wRMkMrWkJogm1r5vuzmTrbKbf7

I pushed the boat out the other year and spent £10 (ish) for the full set. Even though this 70 year old antediluvian penguin already has plenty of reference books so there was considerable duplication of information I already had the money was well spent both for data I didn’t have readily to hand and for a more usefully modern collection of information.

Sherwood and Starrett also do good metric/imperial conversion charts.

Clive

[kevian64]

On kevian64 Said:

On Howard Lewis Said:

Being a Myford, the Leadscrew will be Imperial, as will all the other dimensions and threads, so don’t waste time measuring in Metric.

On a wheel with 125 graduations, each division will represent 0.001″ on the 8 tpi Leadscrew, so if you MUST use Metric, each division represents 0.0254 mm.

But why make life complicated?

In UK we measure fuel consumption in Miles per gallon, not litres per 100 Km

Just use Imperial

Howard

I think you’re right, but I think to make my brain work quicker, I’ll get a conversion table printed out and pinned to the wall behind the lathe.

😊

Howard asks “why make life complicated?”, but I suspect he hasn’t realised that UK citizens under the age of about 70 are more or less solidly metricated.   For boys of 50 and under, Imperial is a unfamiliar complication!

Fortunately not the end of the world when a metric beginner buys an imperial lathe!   Doing so isn’t the smartest move because converting between two systems is time wasting and error prone, but there are  options.   Luckily, Imperial Model Engineers avoid the worst of Imperial simply by working in inches and thou.  That being so a calculator easily does the 1″ = 25.4mm conversion, and conversion charts help too.   Even better, fit the lathe with a DRO, because these display directly in either system.

Also true that the necessary mental skills grow when an operator is obliged to think in both systems, and I guess most experienced UK model engineers can cope with either.   I can, even though though my workshop machines are all metric.  But learning two systems is a PITA, and newcomers may have better things to do with their time.

Kevian:  I guess from the question and the way it’s drifted into metric vs imperial, that this is new to you.   In that case, ask yourself if a lead-screw handle is needed at all?    They’re mildly useful rather than essential, and many lathes don’t have one.   It’s because the need to move the saddle right/left accurately is relatively uncommon.    I fitted one to my starter mini-lathe and used it twice.  Since been using a WM280 for ten years and, so far, haven’t needed a leadscrew handle at all;  it’s absence is a problem I don’t have.

Professional problem solvers are trained to always consider the “Do Nothing” and “Defer” options.   I suggest deferring purchasing a handle because it may not be needed at all.   At this stage, better off learning how to use the lathe, including coping with Imperial!

Measuring the handle end of the lead-screw eliminates all the guesswork.  As knowing how to do this is a basic skill, I suggest concentrating on that.   Do you have a minimum measuring set yet?   I suggest: a steel rule*; a Digital# Caliper; Micrometer;  and a spring caliper set (for taking off dimensions).

* If working in Imperial, may need a few Steel Rules, because they come graduated in eighths, or tenths or twelfths.  My eyesight isn’t what it was so I need a bright light and a loupe to read sixty-fourths, hundredths and < half millimetres.

# Digital Caliper: I use a £5.99 supermarket cheapo for rough work, with mid-range (£50)  in reserve.   The main differences are battery life and feel, not accuracy.  If only the best will do, spend £300 plus on a premium make!  Many prefer dial calipers – no battery to go flat, though they have other disadvantages.

I recommend beginners practise on the machine for a few months.  Not smart to start by dismantling a lathe, looking for faults by measuring, tarting the poor thing up with paint and putty, or rushing to buy every accessory in the catalogue!  Using the lathe in anger identifies trouble and what tooling is really needed.  Trouble is usually due to one of the 3 ‘M’s:   the Machine, the Material, or the Machinist.  Inexperience tends to blame the machine when the real problem is poor technique or a difficult material.

Therefore I suggest using the lathe to make a few things before deciding whether or not a lead-screw handle is needed.  If it is, then the measurement skills acquired by making can be applied to identify which handle will fit.    And after basic skills have been developed, other option is to make a handle on the lathe, it’s what they’re good at!

Dave

[kevian64Participant @kevian64]

Awesome advice Dave, I think you must know me personally lol.

I’m definitely looking at ‘what to buy’ hopefully to make things easier, but I think you’ve hit the nail on the head ……. just use it and learn.

Cheers Kev

[roy entwistleParticipant @royentwistle24699]

Kev,  think that you would find a mandrel handle more useful

Roy

[Peter TuckerParticipant @petertucker86088]

Hi Kevian.

If you drill a 12mm hole in a scrap and try to fit it to your lead screw if it won’t go on you need a 1/2″ bore if it goes on easily it’s 7/16″.

Hope this helps,

Peter.

[Clive FosterParticipant @clivefoster55965]

When it comes to lathe work there is realistically little difference between working in metric or imperial regardless of the units the design is in.

Fundamentally you are removing material until the component is down to size. The size is a number. Whether you need to get that number by converting from imperial to metric, metric to imperial or fractions to decimals rather the reading directly off the drawing hardly matters.

I just write my starting size and finishing size on the whiteboard on the wall at the end of the machine, subtract and divide for the cut, and have at it in as many stages as is appropriate. Magnetic board so the drawing can be right there too. Making sure i’ve set out the right micrometer or vernier t do the measuring. Easy for me as my usual late is dual standard anyway. DRO boxes are the swank answer but I’ve not bothered on the lathes. Essential on a mill tho’.

What does bug me is the direct reading dial on they cross slide of my big lathe which reads the reduction in diameter rather than cut.

Unlike Roy I’d take a lead screw dial over a mandrel handle all the time. Pretty much everything I make has to be parroted off to a length. Vatly easier to set with a lead screw handle or carriage travel dial. Quick tip :- Measure the width of your parting off blade and make a permanent note on your whiteboard, wall or whatever.

Back in the day I’ve used mandrel handles on smaller machines than I now have and honestly not found them sufficiently useful that I’d go looking for, or making, one if they’d not already been in the tool kit. Good for short threads but, frankly pulling the chuck round is little harder for a once in a blue moon job. But, as ever, it depends what you do.

I can see the point if tapping lots of union nuts and similar.

Which I never have.

Clive

[JasonBModerator @jasonb]

Rather than fit a leadscrew hand wheel look at one of the Metric Meek type carriage handwheels with the gears inside that will give sensible metric gradualtions. So should allow fine movements of the carriage.

[Maurice TaylorParticipant @mauricetaylor82093]

Hi, just measured leadscrew extension on my ML7. (1974) It is 7/16 .

Regarding metric and imperial ,I find reading a metric micrometer harder than an  imperial one.

Maurice

[Clive Foster]

On Clive Foster Said:

So far as I’m aware all Myford ML 7 machines, both metric and imperial, used an 8 TPI lead screw.

So the hand wheel will have 125 graduations each corresponding to 1 thousandth of an inch movement of the saddle along the bed when being driven by the handle.

Clive

Metric handwheels can be had diveded into 3.2mm ( 155divs of 0.02mm) which is a reasonable approximation given that one full turn of the imperial screw is 3.175mm

[JasonB]

On JasonB Saidd

Metric handwheels can be had diveded into 3.2mm ( 155divs of 0.02mm) which is a reasonable approximation given that one full turn of the imperial screw is 3.175mm

Well yes but in my view that is seriously bad practice because you have to keep track of the potential errors all the time you are working.

0.025 mm error per turn, 0.1 mm error in 4 turns. Thats 4 thou in imperial native money. In 8 turns it’s near enough 0.2 mm error in 25 mm or 8 thou per inch in imperial. Way too much for sensibly accurate jobs. If going any distance its bad enough keeping track of whole turns without a resettable dial to put either start or, as I prefer finish, on zero.

Such errors mean that its necessary to work out onto pencil and paper, or marker and whiteboard for me, exactly where you need to stop to part off or put a step in the right place when going any distance.

Too much like hard work, especially for a novice.

Graham Meeks geared carriage hand-wheel conversion is, like everything from Grahams drawing board, counsel of perfection. But only appropriate if the machine is already all metric with metric feed screws. Not a beginner friendly project either.

In the long march from 16 1/2 year old neophyte with a seriously crappy Portass S to (nearly) 71 year old with a decent tonnage of quality full size machines in a big shed this antediluvian penguin spent many years working metric, when needful, with imperial only gear. Both machine and micrometers et al.

Quite early on I was told by folk whose skills were beyond reproach that the only sensible way was to do the conversion once for the finished size and work native imperial until I got there.

So far as the machine is concerned where you start and where you finish are just numbers. How you get them is unimportant. All that matters is you stop on the right one.

I was also told in no uncertain terms to “write it down”.

Once written down a metric native funny number is no different to the equivalent imperial conversion funny number.

Whole mm and half mm are comforting but how often do we actually make to even sizes in anything that matters. Usually we are looking for a gnats thingy more to get some sort of interference fit or a touch less for sliding fit, loctite fit or even a bit more less for a running bearing.

Once into the habit of writing down it’s only as small step further, if you have resettable dials, to get into the habit of arranging things to finish on zero.

Gets all the thinking done before you start cutting.

Saves a lot of memory wear and tear and you rapidly get to know what the real world errors are so you can consistently correct for them or at least confirm the expected discrepancy when measuring after the theoretical last cut.

I suspect far too many of our fraternity don’t really trust dials and spend far too much time on cut’n measure then cut again methods.

Until they get a DRO set where working to the numbers is easy.

But when you have saved up for a DRO set it goes on the milling machine first. Frankly I’d consider a DRO on a mill as essential. But neophyte budgets rarely extend to all the essentials, let alone the really nice to have, so priorities have to be set once beyond the just enough to cut stage.

It has to be said that in any discussion of this sort everyone trails their own experience behind them.

I have the utmost respect for Jasons skills along with considerable amazement at his prodigious output.

But clearly he and I grew up in vastly different worlds which is why we often come up with different advice over appropriate techniques. You can rest assured that anything Jason says he has done and found to work. Within the limits of fading memory and human error I try report accurately. Both concerning  things I’ve done and things I’ve been told by the vastly skilled folk who I’ve been fortunate to be advised by.

Clive

[JasonBModerator @jasonb]

I was under the impression that the Meek metric handwheel was geared to give a true metric reading ( would not expect less from Grey)and as it works off the rack I can’t see how changing the leadscrew to metric would affect it’s use?

As for the metric leadscrew handwheel, Yes it is an approximation but will depend on what you are using it for and how you use it. For example if you machine most of your waste away and take a measurement and have say 0.34mm to come off then you can turn the handwheel to that reading then you are down to 2.5microns of error which for many may be perfectly OK.

We often hear people using 1mm = 0.040″ . Or all those imperial mini lathes with metric leadscrews but handwheels in imperial and you don’t hear many problems with that on here.

Having said all that I manage OK without using either the carriage handwheel dial (too coarse) or any lead screw dial 😊. If I did nneed to use the lathe for milling then a plunger type dial gauge does for that and no backlash to worry about.

[Howard LewisParticipant @howardlewis46836]

My lathe has Metric Leadscrews, and is dual dialled, with 118 divisions, each representing 0.001″, but in reality 0.001059″.  IMO, this is an error that can be accepted, particularly since the workshop temperature is not very closely controlled.

Having a Handwheel with 155 divisions, on a 0.125″ pitch leadscrew, each division will represent 0.02048 mm, giving an error of less than half a micron, per division, which should be acceptable for most of the work that we do in our workshops.

Howard

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