Lister Engine Forum

How to / DIY => Everything else => Topic started by: LowGear on February 04, 2018, 01:54:33 AM

Title: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on February 04, 2018, 01:54:33 AM
I thought it would be so easy.  Slow my cheapski stationary belt sander with a router speed control device so I can sharpen knives and the like.  You guys that known the outcome should shed the light upon my wrinkled brow.  As I looked at this https://smile.amazon.com/Work-Sharp-Sharpening-Repeatable-Consistent/dp/B003IT5F14/ref=sr_1_1?ie=UTF8&qid=1517709121&sr=8-1&keywords=knife+sharpener+belt+driven (https://smile.amazon.com/Work-Sharp-Sharpening-Repeatable-Consistent/dp/B003IT5F14/ref=sr_1_1?ie=UTF8&qid=1517709121&sr=8-1&keywords=knife+sharpener+belt+driven) I knew I already had the stuff I needed or I thought I did.  So how do I slow it down and why didn't my brainstorm work?
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: BruceM on February 04, 2018, 02:21:56 AM
If your stationary sander is driven by an induction motor and not a brushed "universal" motor that would be the problem, since routers are brushed universal motors so will take any sort of chopped up power at any RMS voltage and have no starting problems whatsoever.
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on February 04, 2018, 06:25:41 PM
Aloha,

Yup, it's an induction motor.  Probably why it doesn't throw anyone off their balance on start-up.

Thanks for the suggestions glort and going to the trouble to link them in.  I'll look for something like them that runs on 120 and has a gosh bless America plug on it.  PS.  When I was a trained killer I repaired radars in Korea.  I learned a bit of respect and to be careful around stuff that could burn my fingers off faster than I could recite the first letter in my service number.  Shit happens, Lad.

Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: mike90045 on February 04, 2018, 10:35:11 PM
If it's a Induction motor, you would really need a VFD (variable frequency drive) to make it happy.

If you use a Voltage-Regulator-Dimmer-Motor-Speed-Controller  you risk dropping into the starter winding for too long and burning it up. or repeatedly stalling the motor.  Try the cheap route, but prepare for the expensive VFD.  Or consider a new, cheap motor the Voltage-Regulator-Dimmer-Motor-Speed-Controller would work with
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on February 05, 2018, 08:09:38 PM
The good news is that I found the VFD things on Amazon.  https://smile.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=VFD (https://smile.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=VFD) but they're 220V or over $100.  Do they make 120V units?

Casey
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: mike90045 on February 06, 2018, 01:45:02 AM
Grainger has some, single phase 120V

Variable Frequency Drive, 1/4 Max. HP, 1 Input Phase AC, 120VAC Input Voltage  $235

Brand    SCHNEIDER ELECTRIC
Item #    5WJJ5
Mfr. Model #    ATV12H018F1
 argh, it's 3 ph output.   Keep looking

google    single phase vfd
https://www.wolfautomation.com/blog/vfds-for-single-phase-motors/

here's a good write up about the starting winding on single phase motors, and the need to avoid going too slow:
https://kebblog.com/vfds-for-single-phase-applications/


Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: starfire on February 06, 2018, 05:15:13 AM
You can do this job for free. Power the sander with your generator, and slow the generator down. Lower generator RPM equals lower mains frequency equals slower induction motor.....

you're welcome

You can speed it up like this too.
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: starfire on February 06, 2018, 09:13:27 PM
Glort, you are talking rubbish. and again becoming hysterical and dramatic.
Smallish Induction motors are designed to run at 50 and  60 cycles for a worldwide market, and a safe percentage above and below. If they are not overloaded, they will happily run on higher or lower frequencies, exactly as happens with variable speed drives.
A generator should NOT vary its voltage significantly when running above or below its stated RPM, this is the job of the AVR. Even if it did, all motors are rated within plus/minus 20 percent constant. voltage , with substantial safety margins.
What issues with the AVR? Are you saying it will burn out attempting to saturate the stator? Another myth.
The sander in question will be powered by a capacitor start motor,as it is not required to have high starting torque, therefore any centrifugal switch is not present. Increased wear on bearings???  Rubbish.
The rotor in an induction motor has shorting bars, not windings, so how can the rotor be "stressed" above and beyond?
Your suggestion of a VFD is ridiculous for such an application, its likely to cost more than the sander.
The gentlemans query was to slow run a cheap sander easily and presumeably cheaply I believe.
This  also implies intermittent use of the appliance anyway..
You  are  very quick to have an opinion on stuff you know very little about.... google does your thinking i suspect.
Yes, I can demonstrate this, I do this frequently with my drill press, but I wont....... your incessant need to be right, you will poo poo any demonstration and start a slanging match, as you have so done before, and attempting to do now.
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on February 07, 2018, 06:00:54 PM
You know; $70 for a dedicated sharpener is starting to look not too bad.

News Flash!  I have a handheld belt sander that is powered by a brushed universal motor (OK, I looked back through the posts to remember "brushed universal").  Flip it on it's back held down with a couple of clamps and look out dull edges.

Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on February 08, 2018, 07:05:53 PM
Hi glort,

I also use an angle grinder / sander for the mower blades but no one is going to be shaving with these puppies except for some lava here and there.  The chipper blades are ran pretty much the same barbecue.  I do have to be careful about burning them.  But on mower blades if your edge is kinda sharp you're close enough.

I like the belt sander for the machetes and shovels as it's easy to get a good enough edge and I use the machete coarseness as a saw on banana harvests.  Once the stumps turn to paper it's a saw or nothing.  These fancy serrated edges that are left by the full speed 36 grit belt sander don't handle the lava so well.  And a chainsaw only gets the kiss once and it's back to the round file.

This Hawaiian life isn't all samosas for breakfasts at pools edge.  Well, on Fridays it might be samosas on the beach for breakfast but all the other days are work, work and more work.

Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: mikenash on February 09, 2018, 07:56:01 AM
IMHO the 125mm flap disc on the battery angle grinder is just the perfect tool for giving mower blades a touch-up
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: vdubnut62 on March 03, 2018, 04:09:06 AM
I use a 1960's vintage Black & Decker 8" snag grinder that I paid 5 bucks for at a flea market. I got 2 at that price, the thher is from the 50's but needs brushes. Yeah, I'm a cheapskate.
Ron
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on March 03, 2018, 01:29:11 PM
Life moves on boys and girls.

I put the router speed control on the handheld belt sander and when I turned it up side down it fit right into the gaps on a portable work bench I have from a previous craigslist score.  Yeah I sold the far too gone to work gas stove that was on it but I digress. 

It works pretty darn good and that's with a 120 grit belt.  I saw a porcelain 120 grit belt at Lowes that I'll pick up in the next week or two.  The chief's knife is actually kind of sharp but I'm sticking with 36 grit for the machetes, shovels and concrete form scraper (tall banana plant harvester).  I might even break down and get something in the 200 range like the ones the dedicated sharpeners use.  It's only money and Amazon Prime has my credit card number.

Small victories are better if you stop and appreciate the moment.

Aloha
Title: Re: Router Speed Control Device vs. 4X36 Belt Sander
Post by: LowGear on March 04, 2018, 06:38:36 PM
Archie Bunker is alive and living somewhere in Australia!