Digital speed display

[Former MemberParticipant @formermember19781]

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[Former MemberParticipant @formermember19781]

[John RuddParticipant @johnrudd16576]

Bill, many forum members have bought a digital display unit with a probe as a 'kit' from ebay….me personally, I fitted a slotted opto type detector which needed a slotted disc… Easily made. I rewired the socket on my minilathe making use of the lathe's 12v supplies in the speed controller to power the digital tacho readout and the detector….

Many ways to skin a cat.,,,

[Philrob27Participant @philrob27]

I have used the following on my Lathe and Mill. One display which is switched between the machine being used.

https://www.ebay.co.uk/itm/Blue-Red-4-Digital-LED-Tachometer-RPM-Speed-Meter-Hall-Proximity-Switch-Sensor/122667290851?_trkparms=aid%3D555017%26algo%3DPL.CASSINI%26ao%3D1%26asc%3D20151016114640%26meid%3Dbc85103e7d36419abef67507be3291d6%26pid%3D100507%26rk%3D1%26rkt%3D1%26%26itm%3D122667290851&_trksid=p2045573.c100507.m3226

Regards Phil.

[JasonBModerator @jasonb]

I put a green version of the above on my mill last week, biggest issue will be finding somewhere to mount it on a Unimat, what do you have? SL or 3

I just bought a cheap 12V DC supply from e-bay to run it off.

[Former MemberParticipant @formermember19781]

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[JasonBModerator @jasonb]

I managed OK for 12yrs without one on the mill but was just curious to see if I had been doing it right

The factory plug in option does seem quite expensive to me and if one were available for my mill at that cost I doubt I would have bothered. But at £6 you can't really go wrong.

[Peter G. ShawParticipant @peterg-shaw75338]

My lathe has 9 fixed speeds obtained by belt changing. I see no reason for any type of display on such a machine. My milling machine has a constantly variable speed so some sort of means of knowing the speed would seem to be necessary.

I used my cycle speedometer, recalibrated such that the display gave readings which despite being in either mph ot kph were actually the rpm measured. From this I produced a paper chart, stuck behind the speed control knob to give approximate readings. Simple and cheap.

It should be remembered that actual speed is usually not too important in the great scheme of things: often about there will be found to be ok. Therefore why bother with a digital display flashing away merrily and distracting you from what is actually going on?

Neil hit the nail fairly and squarely on the head in his leader in MEW 277. We absolutely do not need the implied accuracy and precision that digital devices purport to supply.

I do accept though, that in the absence of anything else, then digital will probably be the cheapest method of getting an indication of speed.

Peter G. Shaw

[John RuddParticipant @johnrudd16576]

Posted by Bill Chugg on 31/01/2019 14:30:38:

Jason , apologies, first post needs clarifying

I have just had a Sieg C3 400 delivered to replace my unimat 3. Unimat did not have a speed display. Sieg has a socket foe a plug in display. So really wanted to know if members feel worth having.

Thanks

Bill

For the money, no…but as I said in my post above, I fitted a slotted disc to my Super C3, got a spare socket to replace the orig and wired it accordingly….Cost of all the bits inc display from Ebay less than £20…now its worth it…😀

[Richard –Participant @richard-3]

I bought a kit from Banggood for £12 and am using a phone charger to run it!!

[Brian GParticipant @briang]

Cheap eBay tacho showed me just how much too slow I was running the lathe. Hardly gets looked at now, but well worth the fifteen quid it cost to fit one.

Brian

[not done it yetParticipant @notdoneityet]

Like Brian, I fitted one to my lathe a couple of years ago, but have not bothered to transfer it to my replacement. I will get round to it sometime …. maybe. I bought two for a tenner (I think) at the time. The other may get fitted to one of my mills one day. It is easy enough to work out the speed of the Centec by gear and Hz, so the Raglan might be the recipient, if I ever fit it.

[JC54Participant @jc54]

Being a learner machinist but having "tinkered" with electronics I have fitted a tachometer to both of my lathes (a 1906 Drummond and a 1946 Myford/Drummond) and have found them a great help. I do not stick rigidly to the recommended RPM for a job but find the tachos get me into the correct ballpark. I have made my own Tachometers for roughly £10.00 each. Both lathes are running 3 phase motors via inverters. John

[Former MemberParticipant @formermember19781]

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[fishy-steveParticipant @fishy-steve]

I hope you have more luck with it than I had with mine Bill.

I purchased one from an ebay seller in China and it was faulty from the get go.

It would have been more expensive to send it back than it was worth.

Lesson learnt though. I pay a bit more now and only buy from UK based resellers.

Steve.

[not done it yetParticipant @notdoneityet]

Fishy Steve, bang good by any chance? Certainly better not to buy from them if you cannot afford to throw it away, if faulty.

Some chinese customer service is effectively non-existent. I have found the above supplier to be the worst I have come across.

[Harry WilkesParticipant @harrywilkes58467]

I have used the same as Bill and Jason along with a 'retired' mobile phone charger as a power source its a little on the low side but I find it works OK I also found that my hall sensor switched better seeing the south pole of the magnet

H

[Former MemberParticipant @formermember19781]

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[Neil WyattModerator @neilwyatt]

I'm take it or leave it, I made one for my mini lathe but rarely bother switching it on.

On the SC4 it's built in and I do use it, but I always fine tune speed according to cutting performance not tables or calculations.

Neil

[Martyn DuncumbParticipant @martynduncumb88863]

I know the problem has now been solved but just wanted to mention Andrew Whale and his YouTube video on building a digital speed display. His videos are under "Learning Turning". This one is #MT16.

I have built two of them, one for lathe and one for mill and they work very well. They plug in to the socket already provided on the mini lathe and mill. Andrew was very helpful in providing information and guidance.

As remarked, they are not essential, but were interesting to make and I find them useful, particularly on the mill.

Martyn

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