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| Using a bench grinder as a motor for a buffing wheel http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21962 |
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| Author: | patmguitars [ Thu Apr 16, 2009 10:03 am ] |
| Post subject: | Using a bench grinder as a motor for a buffing wheel |
Hey Guys I don't know much about machinery, so here is my question: I have an old bench grinder that very rarely gets any use. I was wondering if that could be used as a motor for a buffing wheel. Here is the tech specifications written on it: 115 volts 3450 RPM 3.3 Amps 50/60 cycle 1 phase There is no HP rating that I can see. Any suggestions? Cheers Pat |
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| Author: | Mike OMelia [ Thu Apr 16, 2009 10:19 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
You need to slow it down. If you were thinking of attaching the wheel directly to the shaft, thats too fast. ~600-800 rpm. So you could use it to drive a 4:1 pulley and get close (on a separate shaft). Lots of folks do that. You could also get one of those Delta Grinders at Lowes that has variable speed (~$70). Then, Caswell Plating sells adaptors to add wheels to such machines. |
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| Author: | Michael Dale Payne [ Thu Apr 16, 2009 11:02 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
yes with proper sheeve set you could use it. That RPM I am guessing it is likely 3/4 HP or greater. you di need a shaft and set of piller blocks as well as the shaft on the grinder is far too short to just attach the buff wheels directly to more leas deal with the speed it is turning. |
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| Author: | Fred Tellier [ Thu Apr 16, 2009 12:29 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
They actually sell slower speed grinders for tool sharpening, but even with the slower speed, the shafts are too short. To get into the waist you need to have the wheel farther from the motor as the diameter of the motor only leaves part of the wheel exposed, thus is in the way when polishing. I currently us a cheap arbor that I picked up at Woodcraft and it is too short but I can use it as more of the wheel is exposed. I will purchase a Caswell 1100 RPM buffer when I get some extra cash as it has long shafts and slower speed. With 10" wheels I am able to buff with a 1/4 hp 1725 RPM motor with equal sized pulleys with no issues other than minimal clearance. Fred |
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| Author: | patmguitars [ Thu Apr 16, 2009 1:02 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Thanks guys I kind of suspected that the short shaft and the high speed would be an issue. I guess that getting a more appropriate outfit would work better. The main problem I face is lack of space. I need a setup that is moveable so I can put it up for use and then store away. I'd be interested to know if anyone has a practical solution to that. Thanks again folks! ![[:Y:]](./images/smilies/smiley20.gif "Thumbs Up") Pat |
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| Author: | Gregg C [ Fri Apr 17, 2009 8:16 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Pat, heres what I did, I ordered a buffer only to get an email that it was back ordered !! So I built one, I used a 3/4 hp swamp cooler motor with an arbor attachment from harbor freight. It's a two speed motor, 1100 / 1750 rpm, I wired it up just like the cooler would be for two speed control, I purchased two 17" buffing pad from Grizzly and stacked them together for a wider buffing surface. I have it mounted on the edge of one of my benches, The thing works perfectly !! Gregg |
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| Author: | Mike OMelia [ Fri Apr 17, 2009 8:28 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Do you have a floor model drill press? viewtopic.php?f=10101&t=21724&p=301164&hilit=drill+press+buffer#p301164 I know a lot of folks say its OK to go to 1100 rpms.... its just that the forces you will experience are quite amazing at that speed. I have been holding my speed under 600 rpm, and a bit higher where risk of catching is low. I still think those "brushed" motors with variable speed control (delta grinder at Lowes) are the best. Mike |
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| Author: | patmguitars [ Fri Apr 17, 2009 8:28 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Gregg said: Quote: I used a 3/4 hp swamp cooler motor with an arbor attachment from harbor freight. It's a two speed motor, 1100 / 1750 rpm, I wired it up just like the cooler would be for two speed control, I purchased two 17" buffing pad from Grizzly and stacked them together for a wider buffing surface. I have it mounted on the edge of one of my benches, The thing works perfectly !! That sounds pretty good Gregg. Do you have any pictures? Cheers Pat |
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| Author: | Gregg C [ Fri Apr 17, 2009 8:47 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
I'll take a couple of pics when I get home, If I can figure out how to post I will this afternoon. Gregg |
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| Author: | Fred Tellier [ Fri Apr 17, 2009 10:44 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
It must be remembered that the larger the wheel diameter thew slower the shaft needs to turn to keep the surface speed of the wheel at a reasonable speed. 1725 RPM seems ok with 10" whells but I would not think that I would want any larger at that speed There is good info on buffing on the Caswell web site http://www.caswellplating.com/buffs/buffman.htm Fred |
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| Author: | Gregg C [ Fri Apr 17, 2009 12:13 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Fred, Your statement is correct, I took that into account when I built this thing, I use the 1100 rpm setting 95% of the time. I decided on the 17" wheel size because I wanted to get as much distance from the bench as I could. Seems to really work well. Gregg |
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| Author: | Frei [ Fri Apr 17, 2009 1:38 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
I use the H/F router speed control on my old milwakee drill, set up as a sort of grinder for blades and stuff. From 3000 to 120. Works fantastic. Its only like 2.3 amps though. I was also looking at it to tune down my bandsaw blade, didnt check the amps needs to be below 8 or 9 amps I think. |
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| Author: | Gregg C [ Fri Apr 17, 2009 6:23 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
How do I post pics, I used the img icon and linked my pics to photo bucket, didn't work. Gregg |
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| Author: | patmguitars [ Fri Apr 17, 2009 7:20 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Gregg I am pretty sure you just click on either the Img or URL buttons, and either paste your image in between the Img brackets or copy you URL address in between the URL brackets. I hope this helps, Pat |
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| Author: | Gregg C [ Fri Apr 17, 2009 7:54 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
My home made buffer  On the right bolted to the bench is the switch box, High / Low On / Off Works great !! 
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| Author: | patmguitars [ Sat Apr 18, 2009 10:16 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Hey Gregg This looks pretty good. I have checked with a couple of specialized stores and a complete set up, including freight would set me back about $450 CAD (about $360 USD). I just want to check a couple of things with you and see if a home made setup like yours is within my technical abilities. You said: Quote: used a 3/4 hp swamp cooler motor with an arbor attachment from harbor freight. It's a two speed motor, 1100 / 1750 rpm, I wired it up just like the cooler would be for two speed control, I purchased two 17" buffing pad from Grizzly and stacked them together for a wider buffing surface. I have it mounted on the edge of one of my benches, I am not sure what a swamp cooler is, but I am pretty sure I can find an electric motor with those specs somewhere close. Could you tell me what kind of arbour attachment you got (I suspect the size has to be a match with the motor shaft, but I just want to know how much it costs and what it looks like)? What kind of on/off switch are you using exactly? Are there any special considerations with things like specific torque, wheel warbling, motor heating, special electrical requirements or any other technical issues that I should be concerned with? Any details on this matter will be much appreciated, Cheers Pat |
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| Author: | Gregg C [ Sat Apr 18, 2009 12:13 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Pat, A swamp cooler is an evaportive cooler, they are very common where I live. I'm sure you can find something like this, however I bet it will set you back a few $$$. If you purchase a motor specifically for a cooler they seem to be more affordable, here in Abq wal-mart has them for $70, the two speeds and the associated rpm's were perfect !! These motors come in two hp ratings, 1/2 & 3/4, I didn't think the 1/2 would be enough so I used the 3/4 hp. If my memory serves me correctly both hp rated motors have a 1/2 shaft, The arbor attachment can be purchased on ebay, here's one http://cgi.ebay.com/Convertible-Motor-A ... .m14.l1262 You should be able to order a cooler motor from Lowes or Home Depot from there web site. Lowes & Home Depot will start to stock these motors right now, summer is just around the corner. The on / off switch is just a metal junction box from Lowes with a two speed cooler switch, the guy at lowes will get you set up. Make sure once you have the arbor attachment in hand you check the diameter of the threaded shaft that the buffing wheel will mount on and get the correct size hole in your buffing wheel. I already had the motor, I had to buy the arbor, motor mount, switch & box & buffing wheel....$40 total, add $70 or so for the motor. Let me know if you need any more help. Gregg |
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| Author: | Frank Aarre [ Sat Apr 18, 2009 1:03 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
patmguitars wrote: Hey Guys I don't know much about machinery, so here is my question: I have an old bench grinder that very rarely gets any use. I was wondering if that could be used as a motor for a buffing wheel. Here is the tech specifications written on it: 115 volts 3450 RPM 3.3 Amps 50/60 cycle 1 phase There is no HP rating that I can see. Any suggestions? Cheers Pat 115 Volts and 3.3 Amps gives you 379 Watts, plenty strong for this, maybe too powerful when you are done gearing it down. if i were to build a buffer i'd want the motor to stall if i was leaning into it. |
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| Author: | patmguitars [ Sat Apr 18, 2009 1:36 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Thanks Gregg, I think I got it down. Frank said: Quote: 115 Volts and 3.3 Amps gives you 379 Watts, plenty strong for this, maybe too powerful when you are done gearing it down. if i were to build a buffer i'd want the motor to stall if i was leaning into it. I found a motor at a local electronic store. Here are the specs: 110 volts 1.7 amps 1500 RPM Do you guys think this would do the job? Not as powerfull as the one Gregg has, but maybe a little less power would be safer, as Frank mentionned. Thanks Pat |
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| Author: | Frei [ Sat Apr 18, 2009 2:00 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Why can't a router speed controller be put on this motor? |
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| Author: | Frank Aarre [ Sat Apr 18, 2009 2:27 pm ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
Frei wrote: Why can't a router speed controller be put on this motor? if it's a brush motor you could probably use router speed controller, won't work with an induction motor though |
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| Author: | Andy Birko [ Mon Apr 20, 2009 7:38 am ] |
| Post subject: | Re: Using a bench grinder as a motor for a buffing wheel |
patmguitars wrote: Thanks Gregg, I think I got it down. Frank said: Quote: 115 Volts and 3.3 Amps gives you 379 Watts, plenty strong for this, maybe too powerful when you are done gearing it down. if i were to build a buffer i'd want the motor to stall if i was leaning into it. I found a motor at a local electronic store. Here are the specs: 110 volts 1.7 amps 1500 RPM Do you guys think this would do the job? Not as powerfull as the one Gregg has, but maybe a little less power would be safer, as Frank mentionned. Thanks Pat 110x1.7=187w or 1/4hp. I use a 1/3hp on one of them stewmac arbors which has I think around a 2:1 reduction and it's enough. I would guess that 1/4hp direct drive would not be enough. Might be enough with a reducing gear. BTW, 1500 rpm is a funny speed for an AC motor. check it out for noise before you buy it to make sure it's not a super noisy universal motor. |
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