Chainsaw tach

[Ashful]

Where to guy a chainsaw tach? I've seen a few here recommend the Stihl EDT, but I suspect that calling my local Stihl dealer (who relies on repair and tuning as a big part of their business) might cause some offense.

Also, has anyone tried using the Frequency setting on their digital multimeter as a chainsaw tach? I imagine a wire wrapped around the plug wire might work as a decent pick-up, if not perhaps just putting the probe near the spark plug wire.

 

[MasterMech]

It's not like you're opening a saw shop in his backyard? Can't imagine taking offense to somebody wanting to purchase the right tools to keep his own equipment running well. Make a couple bucks on the sale and have a happy customer who might need parts in the future.

I have the EDT 7 and it works great. That said, there are other options out there.

 

[kingquad]

I've got a Fast Tach that I bought from edgeandengine.com. I like it.

 

[StihlHead]

I have a Tech Tac TT 20k. It is wireless (but has a wired option), you only need to get the tach a few inches from the saw engine and it reads out the RMP digitally. It works great and has held up over the years. They are about $90 with shipping here (click on link: Edge and Engine). It is the same price as a Fast-Tach which is similar and made by the same company and also available there. Tiny Tach is another similar tach that a lot of people have had good results with, as is the EDT 7.

Disclaimer: No, I do not work for Edge&Engine or DTI.

 

[kingquad]

Check out the "Works Connection Tach" too. They are a wired tach, but are very small so they can be mounted on the saw as a dedicated tach. Pretty cool if you're a tech whore. They are about $40. Need one per saw though, not very practical

 

[HittinSteel]

I've got a Fast Tach that I bought from edgeandengine.com. I like it.

+1

 

[69911e]

I use a DSO201 portable/pocket size oscilloscope. Just bring the probe near the plug wire, look at timing of pulses. These can be had for $60-80 new and are useful for many things.

 

[Ashful]

I have many oscilloscopes at work, and had considered trying one of the cheaper ones for this purpose. Trouble is, our cheap ones are $5k - $6k to replace.

I did try my DMM this evening, and it was reading 600 - 700 RPM's on my idling 036. Not likely!

I like the idea of the DSO201. At 1MHz, I can't imagine using it for much, but it might be just the ticket for stuff like this. Does it have infinite persist, and a long battery life, such that it could be used for power line monitoring over many hours or even a few days?

 

[Ashful]

I have a Tech Tac TT 20k. It is wireless (but has a wired option), you only need to get the tach a few inches from the saw engine and it reads out the RMP digitally. It works great and has held up over the years. They are about $90 with shipping here (click on link: Edge and Engine). It is the same price as a Fast-Tach which is similar and made by the same company and also available there. Tiny Tach is another similar tach that a lot of people have had good results with, as is the EDT 7.

After more reading, I'm down to the Fast Tach by Tiny Tach Inc., and the TT-20K by Tech Tach, both shown here: (broken link removed to http://tinytach.com/handheld.php)

The folks at TinyTach want an extra $20 for the TT-20K, but it can be had at the same price as the Fast Tach over at Edge and Engine, so price ain't a factor. Any opinion on which of these two will work better for chainsaws, and other potential uses? I like the fact that the TT-20K can also be used with a wire harnes, whereas I believe the Fast Tach is only wireless.

 

[StihlHead]

All I can say is that I have never used the wires on the TT 20k that I have. No need to. It has held up well. I know that on the Tiny Tach you cannot replace the battery, and on the Fast Tach the battery is smaller and harder to replace. That is the main reason I got the TT 20 (it has a 9 V. easy to replace battery). It also reads up to 20k, and some of these small tachs are limited to lower RPM readouts. The sample rate is also fast enough to get a good updated reading on. I know the Stihl one has a faster sample rate, but I do not see the need for it. My TT 20 lives in a drawer in my large tool box and it gets used a few times a month on average, and it always works. Any saw, any speed, no problems. One button, simple design and a simple readout that is usable and not too complex.

 

[HittinSteel]

going on 4 years with my fast tach from edge and engine....... has worked perfectly for chainsaws

 

[69911e]

I have many oscilloscopes at work, and had considered trying one of the cheaper ones for this purpose. Trouble is, our cheap ones are $5k - $6k to replace.

I did try my DMM this evening, and it was reading 600 - 700 RPM's on my idling 036. Not likely!

I like the idea of the DSO201. At 1MHz, I can't imagine using it for much, but it might be just the ticket for stuff like this. Does it have infinite persist, and a long battery life, such that it could be used for power line monitoring over many hours or even a few days?

It seems to have relatively long battery life. I have used it for a few hours, and it is reporting over half charge. No, not suitable for long recording periods due to memory limit.
I bought it as I also don't want to move around my good scopes. At 1Mhz it does have significant limits and is not as accurate as a good scope, but I have used it in the past few months to: adjust the speed of the Stihl, check the waveform on auto wheel speed sensors, diagnose a very annoying PS problem with my 3d printer, and locate a break in an underground power line at a friends house using an antenna. I also hand it over to the kids and am not worried like I would be with an expensive scope.

 

[MasterMech]

I did try my DMM this evening, and it was reading 600 - 700 RPM's on my idling 036. Not likely!

How did you set it up? Inductive pickup?

My DMM has settings for 2 and 4 cycle engines. Yours may or may not, remember these things fire every time around, not every other.

 

[Ashful]

Actually, I should fool around with it more, but I just put the high impedance probe close to the coil wire. It's clearly seeing enough field to register, but it's not counting correctly. This DMM just counts frequency and duty cycle, so it would be 1:1 for a 2-stroke.