# MachTach Kit information



## brav65 (Jan 6, 2015)

Does anyone have any experience with this kit (see link below)?  I want to add a tach to my 7x12 lathe and this seems like it would be a fun project.  Any insight would be appreciated.

http://www.ebay.com/itm/MachTach-Ma...127?pt=LH_DefaultDomain_0&hash=item4ae29442b7

Thanks,

Brooks


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## GA Gyro (Jan 6, 2015)

I think WR Miller does... he recommended it to me.


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## brav65 (Jan 6, 2015)

GA said:


> I think WR Miller does... he recommended it to me.




Thanks John!


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## rbertalotto (Jan 6, 2015)

I just ordered one. Now that my lathe is DC variable drive, it should come in handy

www.rvbprecision.com


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## brav65 (Jan 6, 2015)

rbertalotto said:


> I just ordered one. Now that my lathe is DC variable drive, it should come in handy
> 
> www.rvbprecision.com




Thanks Roy let me know how the build goes.  Nice work on the motor conversion.  I am not much of an electronics guy, so I am eager to see what your experience is.


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## Hawkeye (Jan 6, 2015)

I had three MachTachs running on four machines. You will really like using them. I used the Hall effect sensor on all of my installs, with 6 magnets in each array. (You can easily set the number of input pulses to suit.)

Construction is very easy. Instructions are good. If you aren't very experienced with electronic soldering, it would be worth looking up the principles before you start. You basically want to heat the components until they are hot enough to melt the solder, rather than just melting the solder with the iron and hoping it will stick to the PC board and component leads. And make sure to use solder made for electronics - types with acid flux are not good.

When I get my machines back, I'll try to clean and recondition the MachTachs. I really like built-in tachs and these were designed for the hobby machinist.


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## brav65 (Jan 6, 2015)

Hawkeye said:


> I had three MachTachs running on four machines. You will really like using them. I used the Hall effect sensor on all of my installs, with 6 magnets in each array. (You can easily set the number of input pulses to suit.)
> 
> Construction is very easy. Instructions are good. If you aren't very experienced with electronic soldering, it would be worth looking up the principles before you start. You basically want to heat the components until they are hot enough to melt the solder, rather than just melting the solder with the iron and hoping it will stick to the PC board and component leads. And make sure to use solder made for electronics - types with acid flux are not good.
> 
> When I get my machines back, I'll try to clean and recondition the MachTachs. I really like built-in tachs and these were designed for the hobby machinist.



thanks for the info.  I can solder, just not what I would call a professional.  I have replaced batteries in iPods and screens on iPads so am not afraid of the process, I am just not familiar with all of the components and how they interact.  I am a 35 year construction professional and I am used to knowing what I am doing, so now I feel like a kid again working with all these new fields.  I am going to order one and see how it goes.  I am also assembling the pieces to do a DRO using Yuri's design. So wish me luck!


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## wrmiller (Jan 6, 2015)

Hey Brooks,

What Hawkeye said...  

It is a decent kit and I have talked to the owner but have not personally put one together yet. It's on my list for this year.


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## mksj (Jan 6, 2015)

I built and installed the MachTach on my lathe. The build if fairly strait forward, but you need to be careful of the orientation of the chips, electrolytic caps and the LED. The build supplies may be slightly different then the manual, so check twice before soldering. You need to decide if your going to use the plastic case provided or an alternate enclosure.  I ended up with a Hammond metal box, took some planning to get it fitted correctly (I used the double decker circuit boards so it is more compact).  I initially tried the optical, and never got it to work properly, the distance between the optical sensor and reflective material is critical to get right. I ended up using the hall sensor with magnetics, works well and very stable display. I did have one gremlin, which was an issue that I finally resolved. The cable between the sensor and the circuit board is shielded, and normally one grounds the shield at one end. When I did this the RPM readings went crazy, this might because of noise from my VFD or something else. So, start out with not grounding the shield in the cable. Another issue sometimes is noise from the power supply which requires a noise filter which he sells. There also are fully built Tach units for about $100. http://mkctools.com/tachoptions.htm


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## Eddyde (Jan 7, 2015)

brav65 said:


> thanks for the info.  I can solder, just not what I would call a professional.  I have replaced batteries in iPods and screens on iPads so am not afraid of the process, I am just not familiar with all of the components and how they interact.  I am a 35 year construction professional and I am used to knowing what I am doing, so now I feel like a kid again working with all these new fields.  I am going to order one and see how it goes.  I am also assembling the pieces to do a DRO using Yuri's design. So wish me luck!




I just finished building the MachTach and have tested it, works great although I have yet to mount it on a machine.
I am a very experianced electronic kit builder and while it was a fairly easy assembly for me. I think it more of an intermediate kit than a beginner kit. It involves some fine soldering and fitting (IC chips) and soldering the female pins on the sensor cable connector are a bit tricky. The instructions are pretty clear and if you take your time it should be a fun project. However, If you don't have any experiance soldering small parts directly to a PC board it might be a good idea to build a practice kit, Velleman and Chaney make some great cheap kits. Also it would be best to use fine solder and a temrature controlled soldering Iron (or at least a low wattage one), as excessive heat can ruin a component.
Good luck with it. If you have any questions pleas feel free to PM me.


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## Cadillac STS (Jan 7, 2015)

I got one for my lathe.  Works great.  Best thing is that you can easily change to surface feet per minute instead of rpm so you know the speed of the actual cutter.

When I built mine I just had the directions from the web site up on the screen and followed the directions so I could see the pictures as I went.

It is also modular (Sensor plugs in) so you could get one unit and change between a lathe and mill if you had sensors put on both.


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## master53yoda (Jan 13, 2015)

I have a machtack that i switch between my lathe and mill,  I mounted it in with the motor control that also switches between the two,  i use the large treadmill motors on both.    I have had excellent luck with the mach tack,  I actuall leave it set on the FPM more than the tack as that is what you are really looking for anyway.


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## brav65 (Jan 13, 2015)

Thanks for all of the input everyone.  I just got my kit in the mail today.  Now I guess I know what I am going to be doing this weekend!  With me luck on my first electronics project!


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## GA Gyro (Jan 13, 2015)

brav65 said:


> Thanks for all of the input everyone.  I just got my kit in the mail today.  Now I guess I know what I am going to be doing this weekend!  With me luck on my first electronics project!
> 
> 
> 
> ...



IMO you will do fine.  If it were me... I would practice soldering a bit before going after the kit. 
Use a small tip low wattage soldering pencil to solder... excessive heat is not good.

How about a build thread...


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## coolidge (Jan 13, 2015)

GA said:


> IMO you will do fine.  If it were me... I would practice soldering a bit before going after the kit.
> Use a small tip low wattage soldering pencil to solder... excessive heat is not good.
> 
> How about a build thread...



Negative Gyro bad idea on that low wattage iron. If you want pretty solder joints like this board below here are a few tips.

1. Use lead solder its a lot easier. Lead free solder takes more practice. Did you know critical components are exempt from RoHS lead free regulations by the way.

2. The trick to soldering well is transferring the heat very QUICKLY from the iron to the components, then pulling off QUICKLY. You don't want to hold a low wattage iron on the components, the longer you do the more the heat soaks out into the board and components. Typically this is why things go wrong soldering, not enough wattage resulting in having to hold the iron on longer and thus heat soak. 

3. Your components and board need to be clean, and ideally pre-tinned. Your iron also needs to be clean, heat it up, wipe it on a damp sponge to clean off the crud, and apply some solder to tin the tip. Again its about transferring heat quickly and if the iron, components, and board are tinned you are mostly heating the solder, it wets out and flows fast, you will get very quick heat transfer indeed.

4. Use heat sinks to isolate the components from the heat. Go to Radio Shack, they sell packages of 'flat' tipped chrome alligator clips, no teeth, they are quite small, cheap, and make excellent heat sinks.


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## brav65 (Jan 13, 2015)

coolidge said:


> Negative Gyro bad idea on that low wattage iron. If you want pretty solder joints like this board below here are a few tips.
> 
> 1. Use lead solder its a lot easier. Lead free solder takes more practice. Did you know critical components are exempt from RoHS lead free regulations by the way.
> 
> ...



Thanks for the Tips.  In high school and college I built a few small electronic kits.  One of them when I was about 12 was a Sinclair computer.  It was a 16 bit machine with super low res output.  It was fun to learn some basic programing on.  I also spent 5 years as a plumber, so am familiar with how soldering works and controlling heat. I have welded lead for old school shower pans, and braised brass fittings, sot I am confident I will get through it ok. I will get the alligator clips though, I appreciate the tip.  Worst case is that I fry a part and have to replace it.  The cool thing will be using after I complete the assembly.

Thanks again everyone for all the help!


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## Eddyde (Jan 13, 2015)

coolidge said:


> Negative Gyro bad idea on that low wattage iron. If you want pretty solder joints like this board below here are a few tips.
> 
> 1. Use lead solder its a lot easier. Lead free solder takes more practice. Did you know critical components are exempt from RoHS lead free regulations by the way.
> 
> ...


In My opinion, most of what you say is correct. However, I disagree with your comment on low wattage irons.
A low watt iron (say around 25w) is perfect for soldering small components to a pc board, especially IC chips. As long as a fine gauge solder is used (Yes, leaded is best). Heat sinks are great for certain applications but are a unnecessary waste of time soldering ICs, when it can be done safely and quickly by using proper technique. 
Also, The circuit you have in the picture is nothing like the MacTach kit, not the same type of soldering, at all.


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## coolidge (Jan 14, 2015)

Eddyde said:


> In My opinion, most of what you say is correct. However, I disagree with your comment on low wattage irons.
> A low watt iron (say around 25w) is perfect for soldering small components to a pc board, especially IC chips. As long as a fine gauge solder is used (Yes, leaded is best). Heat sinks are great for certain applications but are a unnecessary waste of time soldering ICs, when it can be done safely and quickly by using proper technique.
> Also, The circuit you have in the picture is nothing like the MacTach kit, not the same type of soldering, at all.



I think you are making a bunch of assumptions, I solder IC's and tiny components under a magnifying glass all with the same adjustable to 50 watt station and pencil tip. Nothing wrong with a quality 25 watt iron, I'm saying avoid those $9 cheap 15 watt irons. Here's my station its nothing fancy http://www.mscdirect.com/product/details/83725192


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## arvidj (Jan 14, 2015)

I agree with the previous comments [including cooledge's selection of soldering stations even though it is about 4 times the price of the MachTach kit itself hew:] but feel that item number 3 with any reasonably good iron is *the* most important item ...

_3. Your components and board need to be clean, and ideally pre-tinned. Your iron also needs to be clean, heat it up, wipe it on a damp sponge to clean off the crud, and apply some solder to tin the tip. Again its about transferring heat quickly and if the iron, components, and board are tinned you are mostly heating the solder, it wets out and flows fast, you will get very quick heat transfer indeed.

_The very nice Weller Soldering Station along with an assortment of tip styles that cooledge and I have means nothing if #3 is not followed.

At least that has been my experience.


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## Boswell (Jan 14, 2015)

I have the same Weller soldering station and have been doing thru-hole soldering and some Surface mount for most of my life. Anyway I have my iron set to 700 degF most of the time and almost never use a component heatsink. If your timid then a heatsink might be a good idea but anyone with experience in melting metal to join parts in almost any form should have not real problem with electronic scale soldering. 

As for the MachTach. It looks like a great addition to the tools. I think I am going to have to get one or two (or four ...)


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## GA Gyro (Jan 14, 2015)

Boswell said:


> I have the same Weller soldering station and have been doing thru-hole soldering and some Surface mount for most of my life. Anyway I have my iron set to 700 degF most of the time and almost never use a component heatsink. If your timid then a heatsink might be a good idea but anyone with experience in melting metal to join parts in almost any form should have not real problem with electronic scale soldering.
> 
> *As for the MachTach. It looks like a great addition to the tools. I think I am going to have to get one or two* (or four ...)



Yes, it does look like a good addition... I think since I have one lathe and one mill... maybe two MachTech's for now... 

I am thinking to make a new control box for the mill (left side of the head)... large enough to hold the MT display.
Not sure where to mount it on the lathe yet... OTOH the lathe is not here yet.  When it is here and operational... I am sure where to mount a tack will be obvious.


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## arvidj (Jan 14, 2015)

One of the nice features of the MachTach kit is that you can 'split' the circuit board in half and then stack the two pieces up. This versatility allows you to create something that is only one-half the height of the original circuit board at the cost of a small amount of depth. Really a great idea.


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## Eddyde (Jan 14, 2015)

coolidge said:


> I think you are making a bunch of assumptions, I solder IC's and tiny components under a magnifying glass all with the same adjustable to 50 watt station and pencil tip. Nothing wrong with a quality 25 watt iron, I'm saying avoid those $9 cheap 15 watt irons. Here's my station its nothing fancy http://www.mscdirect.com/product/details/83725192



I don't see how I was making any "assumptions" I was merely going by what you had posted. How was I to know you only meant 15w as being the definition "low watt"? I agree, a controlled station is nice, in fact I have the analogue version of the one in your link. I was trying to best advise someone who may not have the fastest soldering technique down, is only assembling a kit or two and doesn't want to invest $$ in equipment. I go by my extensive electronics soldering experience.


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## brav65 (Jan 14, 2015)

GA said:


> Yes, it does look like a good addition... I think since I have one lathe and one mill... maybe two MachTech's for now...
> 
> I am thinking to make a new control box for the mill (left side of the head)... large enough to hold the MT display.
> Not sure where to mount it on the lathe yet... OTOH the lathe is not here yet.  When it is here and operational... I am sure where to mount a tack will be obvious.




I I am sure with the size of your lathe you would be able to mount the board inside the machine panel. They have some pictures showing an install on a larger Grizzly lathe. You would also be able to power the panel as well.


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## GA Gyro (Jan 14, 2015)

brav65 said:


> I I am sure with the size of your lathe you would be able to mount the board inside the machine panel. They have some pictures showing an install on a larger Grizzly lathe. You would also be able to power the panel as well.



On the front with the elec controls is the logical place... however that means one has to step back to look at the numbers.  

I asked Matt to not mount the head of the DRO on the lathe when he ships it (he is gonna mount the slides).  That way I can put the head where it is easy to look at when 'hovering' over the work... :wavinghi:
At this point I am thinking to get a box for the MT and hang it from the bottom of the DRO... may rethink that when the lathe is here.

THX for your input.


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## Kulpie (Jan 26, 2015)

I replaced the single phase motor on my lathe about 2 years ago with a VFD and a 3 phase motor and I added a pendant style control box with a MachTach inside the box. The input for the MachTach is the optical sensor included in the kit. I wrapped a layer of black tape around the left end of the main spindle, put on 8 sections of the supplied reflective tape and then a wrap of transparent tape to keep everything tight. It has worked fine since installation. The VFD did inject enough noise into the AC line so that I needed to use the filter that you can get from Henry Arnold. It's easy to determine if you have a noise problem by running the MachTach from a battery. If it works from the battery but not from your line connected supply, then get the filter. The direct readout in Surface Feet per Minute is very convenient. BTW, the box came from Home Depot for about $15.


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## rbertalotto (Jan 26, 2015)

I finished and installed my MachTach...Nice kit. Built it all with a 35 year old, 20 watt soldering iron that has built a ton of Heath-Kits and Dynaco Stereo kits.

This board has extremely small lands and the components are really packed in tight. But with a bit of practice, its quite easy.

I wrote a whole article with a video of it working here:

www.rvbprecision.com


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## awander (Jan 26, 2015)

Hi Roy:

I couldn't find the page on the MachTach on your website.



rbertalotto said:


> I finished and installed my MachTach...Nice kit. Built it all with a 35 year old, 20 watt soldering iron that has built a ton of Heath-Kits and Dynaco Stereo kits.
> 
> This board has extremely small lands and the components are really packed in tight. But with a bit of practice, its quite easy.
> 
> ...


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## rbertalotto (Jan 26, 2015)

I just looked and it is the first article


www.rvbprecision.com

or

http://rvbprecision.com/shooting/machtach-metal-lathe-tachometer-build.html


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## awander (Jan 26, 2015)

Ahh-you threw me by putting it in the "shooting" section.......



rbertalotto said:


> I just looked and it is the first article
> 
> 
> www.rvbprecision.com
> ...


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## GA Gyro (Jan 26, 2015)

Good Thread, My thanks to all the folks with experience with the MachTach kits.

Just ordered 2 of the compact (wide spaced boards) kits with green numbers... one for the lathe and one for the mill.  

Now to dust off my HeathKit building skills from many a decade ago.


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## bpratl (Jan 27, 2015)

This is a great kit, I built one for my lathe and another for the drill press. The SFM switch over is a nice handy feature for turning or drilling.


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## rbertalotto (Jan 27, 2015)

> Ahh-you threw me by putting it in the "shooting" section.......



Sorry about that! It's fixed...article is now in "Garage Entertainment" where it belongs....


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