# Tach recommendations for the PM1340GT lathe?



## Alan H. (Jan 29, 2017)

I am evaluating alternatives for a tachometer to put on my PM1340GT lathe that I am outfitting.  

I have searched here and found information but it is a bit scattered, therefore this request for recommendations and experience of installing a tach on a 1340.  

Please share with me your experience in choosing and installing one.  I would really appreciate some photos of your solution. 

Thanks in advance for the help.


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## mksj (Jan 29, 2017)

Hi Alan,
I have a MachTach, but almost never use the SFM or other features. I also had some issues with their optical sensor, their hall sensor version stinks and is difficult to install. I would recommend the generic hall sensor tachometers sold on eBay. They fit well in a Hammond diecast box, just mill out base of the box with a window and snap in the tach display. A attach the cover to the bottom of the DRO with a L bracket. The cylindrical NPN hall sensors on these generic tachs are much easier to install than the MachTach ones, it can be mounted with a simple L bracket.
http://www.ebay.com/itm/Hammond-159...x-Diy-Motley-Mods-fast-shipping-/172377067384
http://www.ebay.com/itm/4-Digital-R...all-Proximity-Switch-Sensor-NPN-/232116655283
http://www.ebay.com/itm/Digital-Red...all-Proximity-Switch-Sensor-NPN-/111360403775

Basic generic tach in a Hammond box on Firestopper's lathe.






MachTach in Hammond box.


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## Firestopper (Jan 29, 2017)

HAHA! I'v been struggling with copy and paste for the past few minutes. Mark beat me to it and did a better job at what I could provide in terms of links.
As far as the pickup goes, I turned a spyder and flush mounted the magnet secured with red loctite. The probe is polarity sensitive to the magnet, so make sure you place it correctly. A red LED light on the pickup probe will lite up when polarity is correct.
Here at 12 o'clock you can see the magnet.




A simple bracket secured to the end cover stud holds the probe directly over the magnet. The air gap is a bit over 1/32" and can be adjusted via threaded probe. You can also see the red LED indicating "pick-up".







If you go with a spyder set up, you will probably need to open up the spindle bore on your end cover as well.




 IMO, adding a spyder is worth the effort and your killing two birds with one stone. Many others have done this on the same lathe as yours with excellent results.




As far as accuracy, I used a hand held laser Tach to verify this $10 tack at different speeds. To my amazement, the tack is darn close.







If you install a VFD for speed control as well as many other options, a tach is a must.
I hope you can use some of these applications.
Paco


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## Bob Korves (Jan 29, 2017)

Accuracy should not be a problem with any of the digital tachs.


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## bss1 (Jan 30, 2017)

Per Mark's recommendation I went with the eBay tach as well. It works great. When running at 60HZ the Rpm's seem to closely match those posted in the manual for the individual gear settings.


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## Alan H. (Jan 30, 2017)

Thanks Mark, Paco and Brad for the feedback.  Ebay is the answer isn't it?

I don't think I would use the SFM function of a MachTach plus Mark's feedback on the sensor helped me eliminate it.  Plus I will save a few pennies with the Ebay approach.


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## Bob Korves (Jan 30, 2017)

Remember that motors are often speed rated at some load, perhaps at full rated load for some motors.  When idling without a load, most motors will be turning faster than the speed listed on the motor plate.  So, do not necessarily blame the tach for a different number than what the motor plate says.  Digital tachs will give accurate results by design.  Only a very poor design would give an incorrect number.


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## xplodee (Jan 30, 2017)

I use a Tachulator which is basically the same as a MachTach. 

I LOVE the SFM setting and use it consistently on my lathe. To me its a more direct way of interpretting speed base lines since i have a VFD installed. I just turn my speed dial until I hit the appropriate surface speed for a given material and im off cutting. 

Imo the surface speed capacity is even more useful on a mill bc the cutter diameter isnt changing like stock diameter on a lathe. But its still a useful lathe tool.


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## Hawkeye (Jan 30, 2017)

MachTach has always worked well for me. I have three of them. I use Hall effect sensors instead of the optical sensor, usually with 6 magnets attached to the spindle by whatever method suits the particular machine.


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## wrmiller (Jan 31, 2017)

My MachTach with the stock optical has given me no problems. I use the SFM feature occasionally.


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## Alan H. (Feb 1, 2017)

Hawkeye said:


> MachTach has always worked well for me. I have three of them. I use Hall effect sensors instead of the optical sensor, usually with 6 magnets attached to the spindle by whatever method suits the particular machine.


Hawkeye, I am curious why you use 6 magnets?


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## Hawkeye (Feb 2, 2017)

MachTach can be set for a wide range of input pulses - possibly as many as 99, IIRC. I just figured that a few extras would add to the resolution at lower RPM.


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## Giles (Feb 4, 2017)

Might be a little crude but, I work on chainsaws and sometimes need a tach to set RPM. I purchased a* 332 Pro Laser Photo Tachometer* and found it also works well on my Lathe as well. You simply place a small piece of reflective tape on the chuck, point the tach at tape and RPM is displayed.







Thanks in advance for the help.[/QUOTE]


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## Alan H. (Feb 4, 2017)

Thanks Giles for the reply.  

You are right, everyone needs one of those and they are relatively inexpensive and typically come with all the reflective tape you would ever need.  It only takes a small piece to do the job.  

I have had one in my tool set for sometime now and I even bought one for my son.  Mine was quite handy on a KMG grinder I built recently to understand the behaviour of the VFD I put on it.  

I have used it on my lathe and mill as well.  So yeap, both machines have their small piece of reflective tape on them and it will stay on both as a backup.


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## jer (Jul 20, 2017)

Has anyone tried a green LED tach? I was wondering if it would compliment the green DRO display or be distracting.


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## davidpbest (Jul 20, 2017)

jer said:


> Has anyone tried a green LED tach? I was wondering if it would compliment the green DRO display or be distracting.



Judge for yourself.   I like mine all green:






Video here:   https://www.flickr.com/photos/davidpbest/35918827891/in/album-72157683014913836/


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## Kamloopsendo (Oct 31, 2017)

This is going to sound a bit simple perhaps but how have you guys attached the magnet to the spindle?  I can see machining a collar or spider but has anyone simply used an epoxy resin on a carefully degreased spindle?
Thanks for the thoughts.
Alex


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## Alan H. (Oct 31, 2017)

If you do not add a spider which would include a socket for the magnet, use a piece of 3M electrical tape.


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## bss1 (Oct 31, 2017)

I had my magnet taped to the spindle with a few wraps of electrical tape for about 10 months before I got around to making a spider. I think it could have stayed that way indefinitely.


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## Z2V (Oct 31, 2017)

The 3m double sided tape would do for sure. It held front license plate on my car at 160 mph


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## jer (Nov 1, 2017)

davidpbest said:


> Judge for yourself.   I like mine all green:
> 
> 
> View attachment 238023
> ...



I tried the green tach. My DRO is a yellow/green display it so happens and the tach is green. I should have just gone with red like most have. It might have looked better. No big deal, next time. LOL.


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