Restoring and Upgrading an Old Sander with 300% More Power | Part 2 of 2

Introduction

In this article, we are rebuilding the big block swapped sander with a massive power upgrade and restoring the sander along the way. If you haven’t read the teardown in part 1, I would start there, it can be found here: 6×9 Sander Restoration and Upgrade Part 1.

Quick Recap

I wanted a powerful metal working sander, at least 3HP spinning at over 3000 RPM, that started and stopped quickly without bogging down. I decided to upgrade my existing 6×9 sander, a 30+ year old import unit that many people have laying around.

Those sell for over $3k and I was able to build this all in for well under $1k, and it looks and performs fantastic!

I outline the process in this article below, but I also am including the video covering the finished rebuild:

Restoration Process

In part 1, we covered the disassembly, so this is assuming you already have your sanding unit in pieces. It is important to be diligent and clean while taking time to do a complete job at every step as they will compound upon each other as we go on.

“The quality of the finished job is always in the prep work!”

So take your time!

Part 1: Cleaning

*If you are following along, you will notice we technically did this step already in Part 1 but if you are doing something similar and starting with a disassembled state, then you will want to clean first regardless.

You will want to wash and degrease your parts, it is important that you remove all of the grease and debris before moving on to the later stages.

Safety First:

Ensure the sander is unplugged. Wear safety glasses and gloves to protect yourself from chemicals, sharp edges, and debris.

Degrease and Wash:

I used my parts washer for this step as it allows me to run a heater degreaser solution, in this case I used Extreme Simple Green Aerospace degreaser as it is one of the only high cutting degreasers that are safe for Aluminum. Using stiff nylon and metal brushes, I was able to remove all grease, grim, and films on the various parts of the sander. This was followed by a thorough rinse and then I blow dried the parts with my air compressor and laid out to dry in the sun.

Part 2: Refinishing

After being cleaned and dried, this is the process where we will begin to bring the disassembled parts back to a new condition or be replaced or upgraded.

Sanding:

Begin by sanding and keying the surface of all of the painted surfaces, this is also a good time to use flat blocks and acetone to remove paint or debris from the machined surfaces. Using a variety of different shape metal bristle brush attachments for a drill will help to get into the tighter sections.

OR

You could use a sand blaster during this time. I did not have one for this rebuild and it would have saved me so much time! I ended up ordering one after this as it would have been a much better solution for this phase of the rebuild, I wrote another article where you can read that here: Sand Blaster Article.

Prep and Masking:

Once you have the parts completely sanded, you will want to wipe them liberally with acetone and lint free towels. After the parts have been wiped and dried, lay the parts out and begin to mask off the machined surfaces and anywhere else you do not want paint. Take time to trim the edges with a razor blade to get a high quality finished job later.

Carefully lay the parts out so that you can reach all sections for paint and set up hangers for the parts expected to be hung for paint.

Sorry, the picture I had for this was too blurry to make out.

Painting:

Using a chemically resilient and scratch resistant paint is important for shop equipment that will see metal use as there is often high temp metal shards and dust flying around. There may also be more exposure to oils and other fluids resulting in a much more strenuous work environment than the original wood-working sander was designed for.

Using whatever appropriate paint you decide on, you will want to start with a light first “coupling” coat followed by two or three medium coats, do not go too heavy as you will end up with drips and inconsistent finishes.

Resurfacing:

As the paint is drying, there are other components that may need to be resurfaced in one way or another. I decided to vapor hone my roller barrels as they were aluminum, so I used glass bead in my vapor hone cabinet to restore these to a like new condition. You could get a similar finish with progressive sanding and some good metal compound.

Additionally, I used steel wool and metal polish to bring back the luster and finish on the bearing shafts and motor’s pulley keyed shaft.

Now that the parts have been restored, refinished, and the paint has cured for over 24 hours, we can start the reassembly process.

Part 3: Step-by-Step Assembly Guide

Step 1. Install the Upgraded Bearings

Since we are planning large power increase, and moving from woodwork to metal work, upgrading the bearings is a good idea. Using a high quality, high precision, ABEC 3 rated bearing with a dual shielded and sealed bearing case, these bearings will be much more suited to support the performance expectation of this machine, I chose to use one of the better known brands here, SKF. High performance bearings are often one of the bigger and more obvious differences between lower and higher quality tooling.

Bearing sizes used for reference:

• Quantity 1: SKF ABEC 3, PN: 6202-2RS
• Quantity 3: SKF ABEC 3, PN: 6201-2RS

The bearings must be carefully tapped into the machined openings evenly, using bearing drivers makes this a quick and easy task. Some bearings are grooved for a retaining C-Clip and others are seated with a circlip retainer, carefully reinstalled these with the appropriate pliers.

Step 2. Unmask and Assemble Upper Assembly:

Start by unmasking the machined surfaces on the cast components. Once the bearings have been installed in the barrels, there is one that is installed in the upper carrier. Carefully, but firmly, tap the roller shaft with the bearing through the barrel and into the carrier housing.

The tension adjustment pins must be reinstalled with the spring and the knurled fittings. I also added lithium grease here for ease of use so that the thumb wheels could rotate easier once under tension.

From here, you will want to install the upright carrier to the cast base, tightening the bolts in a square pattern snugly, but not over tight as these can strip or crack the casting.

Now install the pulley cover to the upright and snug but don’t tighten the cover bolts yet. You will then slide the upper assembly pulley shaft through the upright carrier and then finish bolting the upper assembly and the cover tightly.

Step 3. Physically Install the Motor:

Once the upper assembly has been affixed to the base, we can line up the motor and start taking measurements so that the pulley shaft, feet, and dimension work with the assembled sander casting.

This is where things take a sharp turn from a restoration and become a restomod, but you know, for a belt sander.. The motor we removed was a much smaller motor, ran off of 120v power, and much less torque.

The “Big Block” motor we are installing is a US made, Baldor industrial motor with the following specs:

• 3HP
• 3450 RPM
• Single Phase
• 220v
• 13 Amp
• 56C Frame

In my case, I had several spots that required cutting, grinding, dremeling, and otherwise modifying for clearance, just to get the motor to sit properly in place. Remember that the motor base needs slots in the casting to allow for tensioning of the belt once installed over the pulleys.

With everything aligned, and mounted, install the pulleys with the keys and the set screws at the appropriate and matching interface depth so that the belt is not strained but there is still room for the disc face.

You know, the one we broke during disassembly…

Step 4. Building the Base:

An often overlooked part of building up shop equipment is how structurally substantial and balanced the base is. There is a reason many high quality machines weigh so much more than their cheaper counterparts. More material costs more, but it also typically provided less vibration, less flex in the assembly, and a stronger foundation with which to use the tool against.

I decided to use this opportunity to search Ebay, and find a thick, much heavier tool cabinet base that had a single front door that I could modify for use on this. Bonus for me, the color of the cabinet matches some of my other equipment from JET. This also provides great storage, and I ended up placing all my sanding belts and discs inside.  

You will notice I struggled to drill through the material as it was thicker and harder to drill but made for a great base for the assembled sander. Altogether, the whole system weighs more than double before.

Step 5. Wiring the Motor:

This is the part that scares most people, and it is wise to be cautious as this can be dangerous and/or cause damage to the equipment, your power supply, yourself, etc.

*Please note the disclaimer attached to this article, this should only be handled by qualified individuals and professional electricians.

In my case, my motor did not come with a power cord. I addressed the power outlet this would be used with and the requirements of the motor and my unique circumstance had me installing a 50 amp power cord with the larger gauge wire than required, you can assess your individual wire requirements based on the specifications of your motor.

Additionally, I wanted to add a layer of safety here, and decided to install a magnetic starter switch. I did this because I live in a rural area and sometimes power goes out due to low electrical overhead at my house. If the power goes out for any reason and the machine stops, I didn’t want it to immediately kick itself back on if the power was restored or if I flip a breaker back.

The starter switch also needs to meet the power ratings and in-rush requirements of the motor and the power supply. In my case, 3HP motor, with a single phase 220v power outlet.

Step 6. Make it Mobile:

The shear weight and the size of the assembled sander was cumbersome, so I decided to get some heavy duty casters and welded a base from flat steel sheet to match the dimensions of the sander’s storage base. Since the bottom of the storage cabinet was also open, it gave me some freedom to drill and bolt the casters in, and simply bolt in a steel sheet floor.

*Please note, I am still learning to weld and getting better, but have a LONG way to go!

The caster base was 1/4” steel, so I laid out my clamps and squared it up so I could MIG weld it. All the welds were carefully grinded flat with my flapper wheel to keep the surface flat. This was then prepped and painted with the same process seen above.

As I finished with the caster base, and the magnetic starter switch was wired in from the motor and the cable receptacle, I installed the disc face, the sanding disc and the sanding belt and tensioned everything.

Step 7. Final Assembly:

There were a few pieces missing when I acquired this sander, notably components for the adjustable table. So, I bent some steel, drilled, cut, and shaped it to fit what I needed to hold the table. I also measured and purchased some stainless steel dowel pins from ACE hardware that I was missing. I finished this my cold bluing the small bracket to match the finish of the other brackets and to provide it with some corrosion resistance.

I also decide to add a fold out hanger on the side of the cabinet to loop the 10 foot long power cord on the side.

Step 8. Initial-Power-On, Test and Adjust:

WHEW

This article and the attached video may look like it didn’t take too long, but I had many hours into this project by this stage and I was anxious to start this big block swapped concoction of mine.

**BUT WAIT**

This is when you need to take a second look over the wiring, bolt check all the hardware for tightness, and generally verify everything is as it should be, lined up, and squared away before you put power to it.

With everything good, I plugged in the cable, and flipped the switch and…

IT STARTED!

Immediately, and with much more force, to my surprise (although I shouldn’t have been surprised, I increased the power 300%). The old sander took a second to ramp up and would often bog, but this… this spun right to its rated speed and no matter how much I pushed metal into it, I have not yet gotten it to bog.

As the machine was running, I started to adjust the thumb wheels to get the sanding belt both tight and rotating squarely on the barrels. I couple on and off tests, swinging the upper assembly horizontal and vertical, I was able to confirm a good running condition in all configurations.

This thing is done and freakin’ AWESOME!

That’s a Wrap

This took many, many hours, quite a few special tools that the average enthusiast may not have, but there are likely solutions that don’t require things like a welder or a vapor blaster.

You will notice that I took quite a few pictures during the process, this is an easy way to track and check how things came apart, and more importantly, go back together, especially when projects extend across several working sessions.

So far, the machine has done everything I wanted it to do, works as expected, and has been otherwise a joy and well worth the effort! There are few changes I would make if I did it again, but there always is. Highly recommend this if you want a high power metal sander but don’t want to spend thousands of dollars.

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Disclaimer

The information provided in this blog post is for educational and informational purposes only. It is not intended to be a substitute for professional advice, diagnosis, or installation. Always seek the advice of a qualified electrician or other professional with any questions you may have regarding electrical work or wiring installation.

Performing electrical work can be dangerous and may result in serious injury or death if not done properly. The author and publisher of this blog are not responsible for any errors or omissions, or for any actions taken based on the information provided. Any reliance you place on such information is strictly at your own risk.

Always follow local codes and regulations, and if you are not experienced or confident in performing electrical work, it is strongly recommended that you work with a licensed professional.