building a home made belt sander

7/24/2019 Building a Home Made Belt Sander

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Building A Home Made Belt Sander

by: Robert Frink

Once you own a stationary belt sander, it's hard to imagine life without one. Clamped to a bench inyour shop, these workhorses deburr, contour, polish, grind and shape almost any type of material.The woodworker, knifemaker, home shop machinst, artisian, and craftsmen of all sorts need a beltsander!

One of my addictions in life draws me to garage sales, estate sales, flea markets, etc looking for atreasured piece (junk) for my shop. Almost always, when I find an old motor, I pick it up. Rarely

paying more than $10 or so.

The purpose of this site is to demonstrate a very simple belt sander that can be made from an old

motor very quickly in your shop. I encourage you to use as much "local resource" as possible. Bylocal resources, I mean any old junk you've already got laying around. If I say "use 3/4" plywood"

but you've got 5/8....then use what you've got! These machines are so simple that you really won'tneed to measure much when building them. If it looks right, it probably is.

A quick note about safety

The photos shown here are the way I do things in my shop. I'm not implying that they are safe!You must decide what is safe and you must work within your own capabilities. If you're notcomfortable with anything shown here, don't try it.

Getting started

I've reduced the full size plans and placed it here. I apolgize for the small size. Referring to theplans or photos above; note the 4 main components to this belt sander.

1. The motor with the driver roller (on left)2. The belt support (between rollers) or platen.3. The idler roller and bracket ( on the right)4. The base plate

This is the basis and order of construction.

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Motors

The type of motor that you use will belimited only by your imagination.Generally bigger is better. I like a 1/4hp1725 rpm, it's a popular size and I seem

to find more of them than any othertype. A 3450 rpm also works excellentand if you use one, you'll need more hp,like 1/2hp. The 1/2hp 3450 rpm willgive the same torque as the 1/4hp1725rpm motor but deliver it twice asfast. Since hp =torque x speed, if youdouble the speed....you need to doublethe hp to keep the same torque, andtorque is what keeps the belt moving.

The best choice frame would be a totally enclosed frame, simply to keep out dust. (TEFC...TotallyEnclosed Fan Cooled, TENV...Totally Enclosed NonVentilated) However, if your "localresources" yield an open frame motor for the right price use it. To reduce dust ingestion in an openmotor, I simply run the belt direction away from the motor. Also a dust collector/shop vac isrecommended when sanding. If you breath dust then your motor is breathing dust!

Some motors are reversible, while others are not. If your motor is not reversible, take a minute tosee which way it turns. Looking at the end of the output shaft, if it turns clockwise, you can buildto the drawing. If it turns counterclockwise, then you should build a mirror image of the drawing.

For reference, the motor used on this sander is 1/4 hp 1725 rpm and has good power for a 2" wide

belt. However my rule of thumb here is "more is better".

Rollers

Since the rollers are the most difficult item to acquire, I had to design and make them. More infois here:Belt Sander Rollers .

The driver roller is available for either a 1/2" or 5/8" motor shaft.

The idler roller is press fitted with 2 sealed bearings and fits nicely on a 1/2" bolt.




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Building the frame

First, I rough out some 3/4" plywood for the base plate, the belt support, and the idler rollerbracket.

The base plate was cut to 10" x 24" and set aside.

The belt support and idler roller bracket were made in one piece, then separated as one of the laststeps. They both fasten to the base plate and are located by a key. The idler roller bracket slides onthe key to adjust the belt tension.

Cut out a couple of gussets about 2 1/2 X 5 and set aside. On a 9" X 12" sheet of 3/4 ply, cut twodados the same width as the gussets.

Note the triangle drawn on the face of the board. This helps figure out the orientation of the partsafter they are cut apart.

Rip the board into two pieces about 3 1/4 X 12, and 5 1/4 X 12. Don't get hung up on exact sizeshere, I just made every thing oversized so that I could cut it exact after glue up.

I used a butt joint with biscuits, but use whatever your comfortable with.




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After dry fitting, I glued and clamped everything up. I used the edge of my table saw to try to geteverything as flat and true as possible. Note the wax paper to protect the saw.

When the glue dried, I cut every thing to size at 4 3/4" high X 3" wide.

Then beveled the gussets.




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With the miter gauge on the table saw, I separated the idler roller bracket from the belt support.

* update.... I received a note from a gentleman who built this sander and made a change at this

step. You may need to read through to understand what I did and I think you may like hissuggestion better. Here, I seperate the idler bracket from the center belt support. This way I could

adjust the belt tension by moving the idler bracket around. His idea was to keep this in one piece

and simply slide the whole thing around. What a great idea! It is more robust and makes takes out

a step or two in the construction. The main advantage is that it really stiffens everything up!

The slot in the idler roller bracket must be sufficiently long to provide enough travel to tighten thebelt. Since I had a 1/4" carriage bolt for the fastener, I made the slot by first drilling several holes

with a 1/4" drill bit.

Then chopped out the waste with a chisel.




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The finished slot, down and dirty.

The keyway was cut in the idler roller bracket and the belt support using a dado. I then milled thekeyway in the base plate. Since there is nothing very critical about the size of the key, feel free tochange it so you may use something on hand. Instead of using a dado, you could use a router.

Assembly

From here we can start to assembleeverything. First, I placed the componentson the base board to be sure that I had




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plenty of adjustment for the belt tension.Then spotted the holes for drilling. I useda mixture of blind nuts and carriage bolts

because I had them on hand. Again, usewhateve2`you've got!

The base plate was counterbored on thebottom to relieve the fasteners as shown.

After notching the belt support androunding the idler bracket, they wereassembled to the base plate.

* update... This photo shows how I made

the idler bracket and the belt support in

two pieces but consider keeping them in

one piece that slides on the keyway as

suggested above. You'll need to make

another slot but the additional stiffness

should be well worth it.

The idler roller slips over a piece of 1/2"threaded rod which is bolted to the bracket.Large washers help to stiffen the joint.

After adding the motor, tighten the belt, and complete the belt support by fastening the platen

which the belt rides on. I used 3 drywall screws, but an alternative might be biscuits and glue.




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A residential light switch and enclosure was mounted. Make sure the switch is rated to handle themotor current. At 110V, a 15A switch is good up to about 1hp.

Adjusting the tracking

Don't let the tracking frustrate you! If your machine doesn't track perfect at start up,congratulations, it's just like all of mine. Granted that every thing is reasonably rigid and alignedand the belt is some tension, the belt will not wander due to the crowned rollers. However, initiallythe belt may not track in the center of the rollers. This is easily corrected by loosening the motorand toe-in or tow-out the rollers. Frustration is usually due to over compensation. A littleadjustment goes a long way here.

* update...I've had several questions about "how much tension". I usually tighten the belt just pastthe point where it stops slapping, which is not very tight! But it'll have to be tight enough so it

won't slip. You'll quickly learn.

Operation

Ahhhh! Now that it's completed, notice thedesigned features.

In front of the partial length belt support

(just down stream from the motor) is an areafor "free-form" sanding. The belt supportwas notched out to provide clearance.Basically, the belt is unsupported. Free form




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sanding is great for polishing and shapingwhere the belt is allowed to follow thecontour of the work piece. Note the beltdeflection.

It is important that this "free form" area belocated on the exit side of a roller otherwisethe belt tracking will be upset and the beltmay be thrown off. In this case, the beltsupport stabilizes the belt as it starts overthe idler.

Down stream from the "free-form area", the

belt rides on the platen. This area sandspieces flat. Great for leveling, deburringand beveling.....in the photo on the left, I'msanding the handle flush with the top of themallet head.

The work piece can also be sanded against the rollers. This shot demonstrates the capabilities ofthe 1/4hp 1725rpm motor. It has power to spare... even during heavy contact wheel grinding!

To conclude:I hope that you enjoyed this posting and that perhaps you will build one of thesemachines. My goal was to demonstrate the simplicity of this design and since I'm not "the sharpestknife in the drawer" I'm sure that many people can find ways to improve it. I would like toencourage you.

If you build it,.... have fun and feel free to drop me a line if you have any questions or comments.

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Best wishes,

Rob

Email: [email protected]

Created: 03/01/99Last Rev:07/15/00


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