RDG Graduated Imperial Handwheel for ML7

This topic has 15 replies, 11 voices, and was last updated 23 August 2017 at 08:27 by John Haine.

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21 August 2017 at 20:06 #313253
Andrew Moore 6
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@andrewmoore6
Hello. Please can somebody explain to me how the above works? It has 160 graduations on the scale which, as far as I can tell, represent 5/8" travel of the carriage for each revolution of the wheel.

If I'm right, each graduation therefore conveniently represents 0.00390624" !

LINK

Thank you

Edited By JasonB on 21/08/2017 20:52:48
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21 August 2017 at 20:06 #8839
Andrew Moore 6
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@andrewmoore6
21 August 2017 at 21:30 #313273
Swarf, Mostly!
Participant
@swarfmostly
Hi there, Andrew,

It would seem that someone in RDG's Catalogue proof-reading department was having a 'bad hair day'!!

The lead-screw hand-wheel for the Imperial ML7 is graduated with 125 divisions, corresponding to thou with an 8 TPI lead-screw.

The hand-wheel graduated with 160 divisions is, I believe, intended for use with the Metric ML7 which, interestingly, still uses an 8 TPI lead-screw!

(Try converting your figure of 0.00390624" to millimetres.)

Best regards,

Swarf, Mostly!
21 August 2017 at 21:41 #313274
AJW
Participant
@ajw
I bought one of the 125 graduated handwheels for my ml7, cannibalised the graduated ring off it and fitted it to my original. Made it so I can turn the ring and zero it.
So useful!

Alan
22 August 2017 at 09:20 #313321
Andrew Moore 6
Participant
@andrewmoore6
Hello Swarf I had noticed that, but assumed it was a coincidence. 158.75 graduations would be spot on!

Regards

Andrew
22 August 2017 at 09:44 #313325
Michael Gilligan
Participant
@michaelgilligan61133
Posted by Andrew Moore 6 on 21/08/2017 20:06:39:

… which, as far as I can tell, represent 5/8" travel of the carriage for each revolution of the wheel.

.

Forgive me if I am being thick, but … surely each revolution moves the carriage by 1/8"

MichaelG.
22 August 2017 at 22:28 #313451
Nick Hulme
Participant
@nickhulme30114
Just put the money to one side and save up for a DRO, you'll thank yourself,

Seriously!
22 August 2017 at 23:05 #313457
Maurice Taylor
Participant
@mauricetaylor82093
On the 160 graduated handwheel ,each division represents 0.01984375mm travel along the bed ,near enough to 0.02mm.
22 August 2017 at 23:05 #313458
Mark Rand
Participant
@markrand96270
Posted by Michael Gilligan on 22/08/2017 09:44:37:

Posted by Andrew Moore 6 on 21/08/2017 20:06:39:

… which, as far as I can tell, represent 5/8" travel of the carriage for each revolution of the wheel.

.

Forgive me if I am being thick, but … surely each revolution moves the carriage by 1/8"

MichaelG.

Andrew might be assuming that it replaces the carriage handwheel, rather than being fitted to the right hand end of the leadscrew as it does.

Of course, the 20DP gears and rack on Myfords work out at only a quarter of a percent different from 4mm per tooth, so there could have been some mileage for a metric ML7 to have a calibrated carriage handwheel.
22 August 2017 at 23:27 #313461
Michael Gilligan
Participant
@michaelgilligan61133
Posted by Mark Rand on 22/08/2017 23:05:41:

Andrew might be assuming that it replaces the carriage handwheel, rather than being fitted to the right hand end of the leadscrew as it does.

.

He might indeed, Mark … 'though it is evident by comparison of the photo with this one **LINK** that it does not.

https://www.myford.co.uk/acatalog/A53.-LEADSCREW-HANDWHEEL—METRIC–1430-522.html

That said : Even as an end-of-leadscrew handwheel, the graduations are 'novel' … each division representing 1/160th of 1/8th of an inch.

I suspect that something was lost in translation when they ordered them.

MichaelG.

.

Edit: 1/1280ths of an inch could, I suppose, be interpreted as tenths of 1/128ths … but that's neither fish nor fowl.

Edited By Michael Gilligan on 22/08/2017 23:41:21
22 August 2017 at 23:33 #313462
Michael Gilligan
Participant
@michaelgilligan61133
Posted by Maurice Taylor on 22/08/2017 23:05:27:

On the 160 graduated handwheel ,each division represents 0.01984375mm travel along the bed ,near enough to 0.02mm.

.

But RDG's description of the item says:

Graduated Handwheel for Myford ML7 / Super 7

graduated 0-160 on the scale (Imperial Graduations)

So I can certainly appreciate Andrew's confusion.

MichaelG.
23 August 2017 at 01:35 #313469
speelwerk
Participant
@speelwerk
The original Myford metric handwheel has 159 divisions, which makes it not pleasant to use. Niko.
23 August 2017 at 07:01 #313474
Michael Gilligan
Participant
@michaelgilligan61133
Posted by speelwerk on 23/08/2017 01:35:26:

The original Myford metric handwheel has 159 divisions, which makes it not pleasant to use. Niko.

.

But this RDG one is described as having "(Imperial Graduations)" and makes no mention of Metric. … That's what I find confusing.

MichaelG.
23 August 2017 at 07:51 #313484
Hopper
Participant
@hopper
Posted by Michael Gilligan on 23/08/2017 07:01:39:

Posted by speelwerk on 23/08/2017 01:35:26:

The original Myford metric handwheel has 159 divisions, which makes it not pleasant to use. Niko.

.

But this RDG one is described as having "(Imperial Graduations)" and makes no mention of Metric. … That's what I find confusing.

MichaelG.

I think its a typo by RDG. The imperial handwheel for the leadscrew has 125 divisions of one thou each, giving the 1/8" lead per revolution on the 8tpi leadscrew.
23 August 2017 at 08:04 #313488
JasonB
Moderator
@jasonb
If it is indeed meant for the metric leadscrew I would have thought rather than 160 divs then numbering the larger divs 0.2 would be better, which would give 0.02 per div or 3.2mm per rev. Strangely the Myford metric one reads 3.3 per rev????

What is really needed is a version of the Meek carrage handwheel to gear the leadscrew one down to 3.0mm on the scale per rev
23 August 2017 at 08:27 #313496
John Haine
Participant
@johnhaine32865
The 160 div handwheel assume that 1/8" is 3.2 mm rather than 3.175 mm, so 1 div would be 0.02mm.

"Myford" and "metric" are incompatible concepts! I'd had my "metric" S7 quite a while from new before I realised that it still had an 8 tpi leadscrew. Ah well, CNC has solved that.

Edited By John Haine on 23/08/2017 08:30:19
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