# Surface Grinder



## Sandia (Jul 28, 2013)

What you guys recommend for a 1.5 HP surface grinder. Grinder will not see a lot of use. Would the static phase converter be OK ?


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## Ray C (Jul 28, 2013)

Are you looking for new or used unit?

If it has an integral electromagnetic table, I'd be concerned about using a static converter.  One thing to note, it's the load on a motor that causes more problems with static converters...  Each time you place the motor under load is when the unbalanced power causes additional heat.  Unlike a lathe or mill, once the SG is turned on for use, it's usually on for an hour or more at a time.  It's a slow process.  A lathe is off most of the time...  Setup cut, turn-on lathe, make cut, turn off lathe.  SG's...  It takes 30 to 50 minutes to do 6x8 piece of metal...  Based in that, I think a static converter might not be ideal...


Ray




Sandia said:


> What you guys recommend for a 1.5 HP surface grinder. Grinder will not see a lot of use. Would the static phase converter be OK ?


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## Sandia (Jul 28, 2013)

Ray C said:


> Are you looking for new or used unit?
> 
> If it has an integral electromagnetic table, I'd be concerned about using a static converter.  One thing to note, it's the load on a motor that causes more problems with static converters...  Each time you place the motor under load is when the unbalanced power causes additional heat.  Unlike a lathe or mill, once the SG is turned on for use, it's usually on for an hour or more at a time.  It's a slow process.  A lathe is off most of the time...  Setup cut, turn-on lathe, make cut, turn off lathe.  SG's...  It takes 30 to 50 minutes to do 6x8 piece of metal...  Based in that, I think a static converter might not be ideal...
> 
> ...



Thanks for the advice Ray. What would you recommend instead of the static converter. Maybe a VFD?


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## Ray C (Jul 28, 2013)

Sandia said:


> Thanks for the advice Ray. What would you recommend instead of the static converter. Maybe a VFD?




Absolutely.  I have one on my SG (and about 5 other pieces of equipment).  It's great when you have a new wheel and want to spin-up slowly before it scares the pants off you when 1500lbs of SG starts shaking.  (That problem has all but gone away since I started making hubs with a built-in balancing mechanism). 

BTW: If you get a SG, do your life a favor and get a dust collector...  BTW, Matt at Precision Matthews has a nice SG.  It's the same one Enco sells for something like 3 grand and his is a lot cheaper.  Of course, they're available used but, just as much goes wrong with these as with lathes so, some re-work may be needed.  Usually scraping (or bed bearings) and motor bearings.   I got lucky with mine, it was re-scraped and all new bed gears installed.  It does need an intermediate coupling that connects the motor shaft to the spindle but, it's not life or death yet.






Ray


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## Sandia (Jul 29, 2013)

Ray C said:


> Absolutely.  I have one on my SG (and about 5 other pieces of equipment).  It's great when you have a new wheel and want to spin-up slowly before it scares the pants off you when 1500lbs of SG starts shaking.  (That problem has all but gone away since I started making hubs with a built-in balancing mechanism).
> 
> BTW: If you get a SG, do your life a favor and get a dust collector...  BTW, Matt at Precision Matthews has a nice SG.  It's the same one Enco sells for something like 3 grand and his is a lot cheaper.  Of course, they're available used but, just as much goes wrong with these as with lathes so, some re-work may be needed.  Usually scraping (or bed bearings) and motor bearings.   I got lucky with mine, it was re-scraped and all new bed gears installed.  It does need an intermediate coupling that connects the motor shaft to the spindle but, it's not life or death yet.
> 
> ...



Thanks much for the advice, as I don't know anything about a VFD. I bought a Harig SF and it should be here next week sometime. I was hoping I didn't make a mistake purchasing the SF without researching the 3phase issue first. I would like to contact you once I get the SF delivered and set up and maybe you can give me some leads on what brand and type of VFD to buy and how to wire it up.  My mill is an ACER E-Mill and it utilizes a Toshiba inverter and it sure works well.

Thanks again Ray, you have been most helpful.


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## Ray C (Jul 29, 2013)

I like my Automation Direct GS2 the best of all my VFDs.  I like that it has a mechanical thumb knob to control the speed.  A lot of people use this TECO with good results.  I think it's called an FM50.  Here's a video.  http://www.youtube.com/watch?v=5jVr03ujj8k   All of these units are very, very similar!


Do you have built-in electro-magnetic chuck or will use one with fixed magnets?

Anyhow, you're looking for one with 1 or 3 phase input ranging from 120 to 220 with three phase output in the 220 volt range rated at 1.5 or 2 HP (I'ts ok to get one a little bigger if you want).  Make sure you select one that has a built-in speed switch (either mechanical knob or touchpad button).  Some of the really cheap ones require an external switch for speed control.  

Here's the Automation Direct unit.  They cost a little more so the TECO might be more attractive.  http://www.automationdirect.com/adc...ts_(115_-z-_230_-z-_460_-z-_575_VAC)/GS2-22P0

There's got to be a hundred threads here on how to setup a VFD but, if you get hung-up, you how to reach us...

Ray


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