# Belt sander mod question



## FredM (Oct 30, 2008)

Does anyone know of a good way to mod this belt sander

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2485

to slow it down 3x or so?

Obviously a smaller pulley will work as would some electrical modification but I'm not sure which is easier. I have a lathe so in theory I could make a pulley but if someone has tried and knows it not worth it I will get one with a DC motor and PWM or something.


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## gadget_lover (Oct 30, 2008)

Good question. If it's brushed, one of those "router speed controls" should work, right?

The motor is 3400 rpm, but what's the belt speed?

Daniel


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## precisionworks (Oct 30, 2008)

The pulley is the easiest/cheapest way to slow it down.

Or spend a bunch for a DC motor + PWM control.

Or replace the motor with a 3-phase motor & use a VFD.

Option 1 is the way to go.


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## FredM (Oct 30, 2008)

precisionworks said:


> The pulley is the easiest/cheapest way to slow it down.
> 
> Or spend a bunch for a DC motor + PWM control.
> 
> ...



I think so also but am worried about such a small pulley making an issue with slack in the belt.


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## precisionworks (Oct 31, 2008)

After replacing the pulley, contact a power transmission dealer & tell them diameter of each pulley & center-to-center shaft distance. They will sell you the correct (shorter length) belt.


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## mrsinbad (Oct 31, 2008)

I have the Delta version of this belt grinder... the easiest way to slow it down is to change the drive pulley, which is about 4" diam. If you decrease the size of this drive pulley, you will need to either enlarge one of the other pulleys or modify the idler pulley at the top.


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## Splat_NJ (Oct 31, 2008)

Another vote for a pulley change. BTW, I've had this exact sander from HF for about a year now and love it. An excellent bargain. :thumbsup:


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## modamag (Oct 31, 2008)

have you tried this speed control. It's cheap $15 might do the trick.


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## gadget_lover (Oct 31, 2008)

modamag said:


> have you tried this speed control. It's cheap $15 might do the trick.



Hey! Wait! That was MY suggestion! 



" * Works with any universal AC/DC brush type motor, 15 amps and under "




The only question is whether it's a brush-less motor.

Dan


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## precisionworks (Oct 31, 2008)

> Works with any universal AC/DC brush type motor,



I've never seen any stationary power tool with a universal motor. Portable power tools (woodworking router, electric drill, shop vac, etc) use universal motors, which normally turn around 10,000 rpm in a shop vac, 20,000 rpm in a router, and 30,000 rpm in a Dremel.

If any machine sounds like a shop vac when you hit the start switch, it has a universal motor.


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## FredM (Oct 31, 2008)

I found some people that have modded the much more expensive (but probably worth it) Delta SA180 belt sander.







I also heard some bad things about the HF model along the lines of vibration and belt tracking.


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## VegasF6 (Nov 1, 2008)

gadget_lover said:


> Hey! Wait! That was MY suggestion!
> 
> 
> 
> ...


 
My understanding is router speed controls are only for shaded pole motors. You can't use 'em on a capacitance start motor, which this is. If you have a motor that starts up slow and gains speed like a grinder you can use them. Of course, they have to be properly rated for your horsepower app, but that is never no mind in this case. The manual shows a 124uF 250V start up cap. 


Porter Cable makes an excellent belt sander with the bonus of a disc sander, it is a bit more money I am afraid, but a nice tool. It is a 1700rpm motor, but something like 3400 feet per minute? I dunno if that will help or not. 
http://www.deltaportercable.com/Products/ProductDetail.aspx?ProductID=11470


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## FredM (Nov 1, 2008)

VegasF6 said:


> My understanding is router speed controls are only for shaded pole motors.
> http://www.deltaportercable.com/Products/ProductDetail.aspx?ProductID=11470



yeah thats the one I just linked like ont he post right above yours.


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## VegasF6 (Nov 1, 2008)

FredM said:


> yeah thats the one I just linked like ont he post right above yours.


 
Yah, I was agreeing with you, that they make a very nice product. If you pick it up please let us know how you like it. 

Sorry I couldn't find any that had variable speed. Only the Makita portable 1" belt sander, and I didn't think that was what you wanted. 

Since you stated other people modded it, I am guessing it is still faster than you want?


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## FredM (Nov 1, 2008)

Sorry I am slow I didn't get that you were agreeing with me LOLz!

No I just didn;t want to pay three times the cost of the HF model. It gets down really low with their mods, they are putting 3 way pulley's on it to have it variable speed like the AC lathes have. Its just all told with those pulleys and the sander I'm looking at 160 minimum and the work to fit the pulleys, that doesn't even include belts.


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## fludunlimited (Nov 2, 2008)

you could try one of these

http://www.beaumontmetalworks.com/grinder.html


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## gadget_lover (Nov 2, 2008)

Please tell me that folks are not paying $1,000 for a two inch belt grinder. 

Yeah, it looks fairly solid, and I know that some parts are a hassle to make, but $750 for a single speed unit without a motor?

But wait! There's more! The VFD motor and controller package is only $1,088 more!

Is it just me, or does that seem.... excessive?


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## precisionworks (Nov 2, 2008)

> Please tell me that folks are not paying $1,000 for a two inch belt grinder.


I would have gladly paid $1000 for my Burr King 482 (48" x 2" belt) ... but had to pay over $1600 for a new one.



> But wait! There's more!


My VFD was $350, and the 3 hp Baldor was about $100, so my machine total is just over $2k. Considering that it runs every day that I'm in the shop, it's been one of the best investments I've ever made.


The KMG is a nice machine, especially if you need a large diameter contact wheel for hollow grinding knife blades. There are plans to build a KMG copy, available on the web, which would allow some cost savings. You'd probably have $300-$400 in parts, not counting the motor (and VFD if you want variable speed). For me, the speed control is essential, and the Burr King, the Delta belt/disc machine, and my wire brush machine are all VFD controlled, running 3 hp motors.


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## gadget_lover (Nov 2, 2008)

Please forgive my ignorance, but what features / attributes of that sander make it worth so many times more than what I paid for my belt sander?

I probably should not ask, since I'm happy with what I have... ignorance is sometimes a good thing! But I like to know what defines a good tool, so I'll ask anyway.

Since the moving belt is the main consumable, and will fit on many different machines, that can't be it.

The bearings are off the shelf, but I've seen some seriously accurate, seriously expensive bearings. Is that where the money goes?

Daniel


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## lightmyway (Nov 2, 2008)

The KMG belt grinder was designed for knife makers and industrial applications and is one of the best available. It is very versatile and easy to modifly,and will last a lifetime and priced accordingly.


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## precisionworks (Nov 2, 2008)

> but what features / attributes of that sander make it worth so many times more


That's an excellent question ... here are the features that come to mind.

The frame, especially on the Burr King, is a heavy aluminum casting. It provides a rigid mounting platform for the contact wheel and the two idler wheels. It is substantial enough that the belt tension & belt tracking adjustments are easily made, and stay where they're set. I owned & sold quite a few lower priced machines, and none did a good job tracking the belt.

The drive wheel & idler wheels are precision machined to have the slightest crown, hardly visible to the eye. Many machines use flat wheels which are hard to track. Bearings are precision electric motor bearings, sealed to keep grit out.

You have a choice of three sanding/grinding modes. The contact wheel is used for aggressive stock removal. The space above the contact wheel is used for slack belt sanding, which is really gentile. The platen & work rest can be swung into place to give the same belt support as a backstand sander, which is nice if you need to grind a certain angle or a right angle. 

The motor (again on Burr King) is an American made Baldor, totally enclosed to exclude sanding grit. Even the smallest 1 hp motor would cost about $300 (retail), and the 2 hp and 3 hp motors are more expensive yet.

When a machine is built this well and this heavily, it can easily run for years in a tough factory environment. In a home shop or small commercial shop, they're nearly impossible to wear out. Some interesting testimonials here: http://www.burrking.com/testimonials.html







The Burr King 482 is the green machine in the lower right corner. The VFD is the blue box at upper left. The belts go from 24 grit to 600 grit, plus Scotchbrite & cork.


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## gadget_lover (Nov 2, 2008)

Thanks for the info. That's a nicely worded post. 

I was not aware that a sander was such a mainstay for some businesses. I do understand that some hardware is better designed and constructed than others. Some is vastly superior.

I just find it hard to justify large sums for relatively simple devices. For $1000 I can buy some fairly complex machinery (lathe, mill, camera), so I guess that sets my expectations a bit high. 

But there is a lot to be said for being able to buy a machine with a great reputation and know that it will work when you need it. That can be worth a lot all by itself.

Daniel


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## fludunlimited (Nov 3, 2008)

gadget_lover said:


> Please tell me that folks are not paying $1,000 for a two inch belt grinder.
> 
> Yeah, it looks fairly solid, and I know that some parts are a hassle to make, but $750 for a single speed unit without a motor?
> 
> ...


 
its kind of like when you get a lathe and then buy the cheep 
tooling. the quality of your work is so much better with the good stuff.
I bought a grizzly grinder and could not make a knife to save my life
but with my kmg I can make a pretty good blade.

Im in it about $2300 and still have more atachments I want.
I have the kmg with a flat platen, Small wheel attachment, 10 in wheel
2 hp Variable Speed motor and VFD.

I want the Rotary Platenbut its $473.


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