Laser Tachometer

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Laser Tachometer

This topic has 25 replies, 8 voices, and was last updated 9 May 2019 at 17:36 by Adam Harris.

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29 June 2012 at 10:57 #22133
The Merry Miller
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@themerrymiller
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29 June 2012 at 10:57 #93300
The Merry Miller
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@themerrymiller
Morning all,

Has any member purchased a tacho similar to the one in the image below (from e-bay I might add).

If so, I'd appreciate comments on it positive or otherwise.

Len. P.
29 June 2012 at 11:58 #93304
Les Jones 1
Participant
@lesjones1
Hi Len,
I have a similar tacho to the one in your picture. Mine has an attachment that clips over the end so the spindle that sticks out of it can be held against the shaft being tested. Mine gives accurate readings both optically and when used with the attachment. I think I bought mine from CPC a few years ago. Mine looks the same as Ebay item number 170657996588 or CPC item IN02507 I think I paid about £20.00 for it. ( Not the £41.95 that CPC have it for at the moment.) I suspect all of these devices are the same basic design.

Les.
29 June 2012 at 14:11 #93317
The Merry Miller
Participant
@themerrymiller
Hi Les,

Was your tacho anything like the 2 in 1 version seen below. (on e-bay for about £14.50)

Len. P.
29 June 2012 at 14:41 #93320
Les Jones 1
Participant
@lesjones1
Hi Len,
It is similar to the one in your picture but closer to the one I mentioned on Ebay and on CPC's website. This is one of the pictures from the Ebay advert.

Les.
30 June 2012 at 12:55 #93395
Keith Long
Participant
@keithlong89920
Hi Len

I bought one of the units as in your original post – it cost (from memory) £8.50 INCLUDING postage from Hong Kong!

It works just fine for the use I have for it, checking lathe and motor speeds. I came with some sticky refelective strip to produce the marker pulse, but I've found there is usually enough contrast somewhere on the rotating bit that you don't need to bother. A dab of "snopake", white or black marker pen on a shiny shaft usually works just as well.

I usually just point it at a flourescent tube as a quick calibration check and if I get a reading of 6000rpm+/- a bit I'm happy, as generally I'm not looking for measuring speeds to high accruracy.

One point to watch is that there is no on/off switch on mine so the battery drains all the time, albeit at low level, so if you plan to use it infrequently it would pay to take the battery out for storage.

Mine does exactly what I wanted it for, at a LOT less than I could build a unit for in terms of time and effort. Very satisfied.

Keith
30 June 2012 at 13:42 #93398
The Merry Miller
Participant
@themerrymiller
Thanks for your input Keith,

Les, does your Tacho have an on-off switch?

Len. P.
30 June 2012 at 17:14 #93415
Les Jones 1
Participant
@lesjones1
Hi Len,
There is no on/off switch on my tacho but there is a button to press when you want to take a reading. I have measured the current when the button is not pressed. It is about 150 micro amps so it would discharge the batteries over a period of time. It is worth removing the batteries when it is not in use as Keith suggests.

Les.
2 May 2019 at 18:43 #407521
Adam Harris
Participant
@adamharris13683
So Len.P. did you buy one of those cheapo DT-2234C laser tachometers offered on ebay today around £9, and are you also as happy as Les with it? I wonder if it is a waste of time because the cheapest today on CPCFarnell is £37….Any body else have a cheap type to recommend?

Edited By Adam Harris on 02/05/2019 18:49:43
2 May 2019 at 18:49 #407522
JasonB
Moderator
@jasonb
Len passed away a year or so ago.

I have one of the tachos and it works OK for me on the odd IC engine or mill spindle.

Edited By JasonB on 02/05/2019 18:54:43
2 May 2019 at 18:51 #407523
Adam Harris
Participant
@adamharris13683
Jason sorry to hear that. I just want out of interest to check my lathe spindles and milling spindle 0rpm – 3000rpm. Should I buy one of these DT-2234C tachos?
2 May 2019 at 19:01 #407524
Adam Harris
Participant
@adamharris13683
Great video! So it works fine.I will take the plunge. Thanks
2 May 2019 at 19:01 #407525
JasonB
Moderator
@jasonb
Yes it will work for that, I've use dit a few times on the mill and to check the built in tacho on the lathe. It comes with some strips of reflective tape which may be needed depending on what surface you shine it on.

Though for the same sort of outlay you can get the little tachos with proximity sensors and fit one of those which will give you a read out all the time. I have one on my mill now. This sort of thing

Edited By JasonB on 02/05/2019 19:03:22
2 May 2019 at 19:34 #407528
Adam Harris
Participant
@adamharris13683
Thanks. And thanks for the nice video!
2 May 2019 at 19:40 #407530
Tony Pratt 1
Participant
@tonypratt1
Posted by JasonB on 02/05/2019 19:01:13:

Though for the same sort of outlay you can get the little tachos with proximity sensors and fit one of those which will give you a read out all the time. I have one on my mill now. This sort of thing

Hi,

Has anyone got an idiots guide to wiring up the 'little tachos' as linked above? I have the display, ribbon cable & sensor, thanks in advance.

Tony
2 May 2019 at 19:42 #407531
JasonB
Moderator
@jasonb
You can also just read the numbers on it but a magnifying glass will help
2 May 2019 at 19:45 #407532
Adam Harris
Participant
@adamharris13683
And do you have to fix the little magnet to the spindle ? How far must the proximity switch/sensor be to the magnet?

Edited By Adam Harris on 02/05/2019 19:46:01
2 May 2019 at 19:47 #407533
Adam Harris
Participant
@adamharris13683
I've just bought the DT-2234C but might also try one those permanent installations
2 May 2019 at 19:58 #407535
JasonB
Moderator
@jasonb
I just cleaned the spindle with acetone and then stuck the magnet on with Araldite, check magnet is the right way round first. Gap can be upto about 10mm but less is better.
2 May 2019 at 20:11 #407537
Tony Pratt 1
Participant
@tonypratt1
Jason B,

Thanks for the excellent 'guide'!!!

Tony
2 May 2019 at 20:26 #407539
Adam Harris
Participant
@adamharris13683
I think it would be a useful tool when I am running the 3-phase 50 hz 400v motor (sadly non-dual voltage), with a 230v inverter setting inverter parameters pretending the motor is 230v 29hz – full torque up to 29hz but moving to higher frequency the torque declines such that one might not be able to reach the intended higher spindle speeds. This would be great for seeing real speed in such circumstances.

Edited By Adam Harris on 02/05/2019 20:27:20
3 May 2019 at 10:29 #407580
fishy-steve
Participant
@fishy-steve
Posted by Adam Harris on 02/05/2019 19:47:36:

I've just bought the DT-2234C but might also try one those permanent installations

Hi Adam,

Wish I had seen your post earlier. I purchased the same tacho that is in the picture of the first post.

It didn't work. It was a piece of junk. Hope you have more luck with yours.

Steve.
3 May 2019 at 13:27 #407599
Adam Harris
Participant
@adamharris13683
Thanks Steve, a bit late but I shall remain hopeful as JasonB demonstrates using the exact same model too. Well I can suffer £9 loss but actually ebay pretty good at getting money back for buyers when item faulty. I will let you know as soon as it arrives next week
3 May 2019 at 13:46 #407600
Harry Wilkes
Participant
@harrywilkes58467
Posted by JasonB on 02/05/2019 19:58:00:

I just cleaned the spindle with acetone and then stuck the magnet on with Araldite, check magnet is the right way round first. Gap can be upto about 10mm but less is better.

Sensor needs to see the south pole of the magnet, mines been working now for around 3 years without any problem I use a mobile phone charger to power it .

H
9 May 2019 at 17:34 #408461
Adam Harris
Participant
@adamharris13683
Absolutely delighted with this £9 purchase on ebay (many sellers offering it). Tested on the trusty Super 7. Gizmo comes in nice little blue pouch. It comes with sticky reflective tape. Snip off a bit, stick it on the chuck, and aim the laser device at it. So on theoretical slowest belt setting of 210rpm, gizmo shows 237 rpm, and on fastest theoretical belt setting of 2105 rpm, gizmo shows 2093 rpm. Could not be more pleased! Pictures to follow…

Edited By Adam Harris on 09/05/2019 17:35:57
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