Rebuilding a US Electrical Tool Model 500 Grinder

Several months ago I spotted a US Electrical Tool Model 500 grinder for sale on Garage Journal.  I had been looking for one of these grinders for quite a while and this one was priced right!  It was also about 10 miles out of my way on a planned trip up north.  I picked up the grinder last month and began the process of rebuilding it to as-new condition.

The machine, serial number 39 43 55 was produced December 1946 as one of an order of 14, likely for the US Government.

Here it is as it arrived at my shop:

And here it is as I begin rewinding the motor!

To follow along on this rebuild check out my threads on:

Practical Machinist

Garage Journal

Old Woodworking Machines

 

Flooring Back Underway!

I’ve been busy the past few days making parquet flooring for the house.

The whole thread can be found here on Garage Journal:

“A Herringbone Parquet Floor From Scratch”

New Forklift Forks!

Since I bought my 60′s Clark CY-80 I’ve been using the shop-built forks that came with it.  This hasn’t particularly thrilled me in the slightest, but they did load test OK.

Recently, I purchased a set of used 10,000lb. forks and learned a little bit about forklift fork inspection in the process.

But first, here are my new forks!

Fork Inspection

The forks are one of the most highly stressed parts on a forklift.  They’re also one of the parts most likely to be battered and damaged in service.  Obviously, some level of attention should be devoted to their inspection.  One of the most stressed parts of the fork is the heel, where the fork bends 90 degrees.    I just so happens that this is the part most likely to sustain damage under normal operation!

Many forklift operators unknowingly damage the forks by dragging the heel along the ground, wearing away the thickness of the fork.  ANSI / ITSDF standards recommend that forks be replaced when the thickness of the heel has worn to 90% of original thickness.  At this point, the load carrying capacity of the fork has been reduced by approximately 20%.

For more information on fork inspection and wear limits, I recommend reading Cascade’s “Fork Arm Wear Guide”, part of their fork caliper inspection kit.  The “Fork Arm Wear Guide” can be downloaded from their website by following this link.

Cascade Corporation: Fork Arm Wear Guide

Gravity and Indicators

Grab your favorite mag base, thousandths indicator and a nice piece of lightweight steel tube about 9″ long for this experiment!  Clean up the tube and stick it to the underside of the mag base.  Then, holding on to the indicator base block, zero the indicator like so:

While keeping a firm grip on the indicator base and not touching the indicator arm or the tube, invert the whole setup (holding it above your head makes this easier) and read the indicator:

You might be surprised just how much your favorite magnetic base flexes under its own weight due to gravity.  In my case, the indicator difference  between upright and inverted was 3 thousandths of an inch.  Factoring in cosine error makes the actual difference about 2.6 thousandths of an inch.

Something to think about…

Bench Vises and Easter Bunnies

Bench vises are one of those things that seem to be overlooked in most shops, maybe because they’re so ubiquitous.   I never really paid much attention to vises or even thought about them until my friend Mitch began rebuilding old American vises.  If you spend much time around here, you’ll find I have an attraction to all kinds of old things.

Some people would say why bother rebuilding something as simple as an old vise when you can go out and buy a new one?  It’s just a vise, right?  WRONG!

For one thing, they really don’t build them like they used to.    Take my 6″ Morgan Chicago for example.  It was built sometime in the 1930′s and spent most of its life on a workbench in a Studebaker truck plant.  A wire wheeling and a fresh coat of paint and it’s hard to tell it was bolted to a bench sometime before the second World War.  Two generations used this vise in an industrial environment before I got it:

This vise has 6″ jaws and weighs right at 150lbs.  Compare those figures to the the cheap piece of Chinese junk below.  The Chinese vise is advertised as having 6″ jaws and weighs only 70 lbs.  I ask:  where’s the beef? There isn’t any, obviously.

You’re probably wondering about now  “Where does the easter bunny part come in?”  Have another look at the cheap Chinese vise above and you’ll note that, on the whole, it looks similar in size to the Morgan.  So why does it only weigh half as much?  If you buy a Chinese vise you’ll soon figure out why:  Because they’re hollow, just like those big easter bunnies you used to get as a kid!

The owner of the broken Wilton above had the following to say about it on Practical Machinist:

Broke after its 3rd use!

This was purchased at Lowes. Horrifying quality. All pot metal. Rust UNDER the blue finish.

Note the shrink wrap still on the anvil section. It was brand new when it broke holding only a small car part.

So, when you’re thinking about a bench vise for your shop, ask yourself:  “Do I want a bench vise or an easter bunny?” If a bench vise is what you need, hit the classifieds or the local swap meet and look for some old American iron.  If an easter bunny is more in line with your requirements, buy a Chinese vise and keep the receipt.  You’ll need it.

For more information on bench vises, check out the following links:

Garage Journal: Everything You Need to Know About Bench Vises

Practical Machinist: Vise Squad, Let’s See Yours

Rigging and Transportation Planning, Part 2

In Part 1 I showed how I prepare in advance for rigging day.  Now, in Part 2 I’ll show what happned when rigging day arrived.

I remember reading a post on Practical Machinist regarding the rigging of a large vertical boring mill into its machinery pit.  The poster stated that the rigging crew was all over 60, moved slow as molasses, never yelled or seemed impatient and moved a 100,000lb machine into a machinery pit over the course of an afternoon with no hiccups using only what they brought in the back of two pickup trucks.

Regardless of whether the story is true or not, there is a lesson in it.  I think that lesson is:  Be prepared, have a movement plan taking into account the machine type,  and move slowly to catch problems before they become disasters.  DON’T GET IN A HURRY!

Keeping that in mind here’s how the rest of my plan unfolds:

Rigging Day:

With the machine on the way and due around noon, now was a good time to take care of any last-minute issues.  One issue that cropped up was making sure I had enough Propane on-hand.  After that, it was simply a matter of waiting.

Sometime past noon, the machine finally arrived.  One last check of the movement plan and it was time to get started.  After un-tarping the machine, the first order of business was to give the machine a once-over to look for any damage.  Now is a good time to take photos from all angles, especially if you’re not going to be the one moving the machine, or if damage caused by the trucking company is noted.

In this case, I did note some superficial damage.  Despite my instructions, the trucker used chains across the ways of my machine!  Luckily, this is an American Pacemaker and the ways are made from tool steel hardened and cryogenically treated to Rockwell 62C to 64C.  This makes the ways much harder than a load binding chain and so the softer  load binding chain took all the damage.  However, the chain still left a little rub spot right in front of the headstock on the front way:

Note:  Any damage of consequence should always be noted on the bill of lading before signing it and handing it back to the trucker.  If you do not note the damage on the bill of lading, you’ll have no recourse.  Photos help here as well.

Once I determined the machine was undamaged it was time to begin the rigging operation.  In my plan, I noted that many machines receive damaged handwheels and front side controls when rigged.  In attempt to combat this problem, I removed the largest projections from the front side of the carriage.  As can be seen in this photo, the cross slide speeder handle was a prior casualty:

Once the protruding controls were removed I set up the slings and rigging bars.  From measurements taken off the machine weeks earlier I knew how long the slings and rigging bars needed to be.  Using American’s rigging instructions as a guide, I set up the slings to fit over the forklift forks in a reverse basket:

Once everything was in place I took out the slack and made a test lift.  The machine is very headstock heavy which caused additional stretch in the headstock side sling.  A 4×4 over the headstock side fork took care of this problem:

The moment of truth was here.  I lifted the machine off the trailer and had the truck drive out from under the machine.  I find this best when possible, as the torque moment around the front axle of a reversing forklift reduces the available lifting capacity.  Once the truck was out from under the machine I carefully lowered it close to the ground:

Moving the machine into the shop was a challenge.  Luckily, I ordered a forklift with sideshift capability.  This came in handy for scooting the rear of the machine into the door sideways, one foot at a time:

Once the rear of the machine was on the floor I straightened it out and picked up the back end to slide it in.  I had planned this maneuver in advance as there was one inch of clearance between the top of the machine electrical cabinet and the concrete door beam.  Another reason why it pays to take a tape measure when inspecting machinery!

Once the machine was though the door the real work could begin, skating the machine into final position.  One lesson I learned here is that it is best to use support the machine with three skates rather than four.  With four skates, any uneveness in the floor will cause a skate to slip out from under the machine.  Using three skates eliminates this problem.  Errant skates are a prime cause of flipped machines, so it pays to go slow and watch them like a hawk.

Putting the headstock end on skates:

Finally!  The machine has landed:

Rigging Day + 1:  The After-Action Report

After a rigging job it is always a good idea to sit down and survey what went right, what went wrong and where things could be fine-tuned.  In this case my forklift planning was very good, but I had not considered a few things when skating the machine.  Using four skates, I had to be extremely careful to ensure the skates stayed under the machine.  In future, I will use three skates to accomodate the uneven floor.  Because machine tools do not flex, it only takes a small change in the floor to completely unload a skate.

Another thing that could have gone better involved the rented toe jacks.  When initially jacking the machine I noted one of the toe jacks was out of oil.  I was able to fill the jack with hydraulic oil, but did not sufficiently bleed out the air from the lifting ram.  This caused the jack to allow the tailstock end of the  machine to freefall between 1/4″ and 1/2″ resulting in a hard landing.  To a degree this was not forseeable, but is a good case for buying and maintaining my own rigging equipment and taking further care when using rented equipment.

Hopefully, this post has given you a few ideas when it comes time to rig your next (or first) machine.  If so, let’s hear about it!

Rigging and Transportation Planning, Part 1

So, you just saw an ad for some new must-have machine that’s on your wish list.  If you’re a heavy iron addict like me, you know that paying for the machine is the least of your concerns.  Before I hand over the cash I already have a rigging and transportation plan in place to move it from the seller’s location to my shop.

In this post, I’ll discuss how I plan the rigging and transportation of a new machine using a real-world example:  Moving my 1970 American Pacemaker engine lathe.

Before Purchasing:  Knowing and Assessing My Limitations

Dirty Harry said “A man’s gotta know his limitations.”  The first step of a rigging plan is determining whether my capabilites are adequate for the move and how I can use them.  There are numerous places I could begin, but I like to take a top-down approach.  The top, in this case, is the manufacturer’s written instructions.

Most machine tool manufacturers publish rigging information in the operating manuals of their machines.  I begin by studying them carefully and comparing the instructions with my equipment.  Many times, the instructions will include an illustration of the recommended way to lift the machine, along with a basic equipment list.  The operating manual should also list the weight of the basic machine, plus accessories.

Here are the rigging instructions for my machine, an American Pacemaker 14″ x 30″ “Style B” engine lathe:

With the rigging instructions in-hand, I asked myself:  Am I capable of safely performing this rig?  If so, what equipment will it take to safely move and rig this machine, following the manufacturer’s instructions as closely as possible?

I decided that I had sufficient experience, but did not have the right equipment.  However, a survey of available options concluded that the equipment could be rented at a reasonable cost.   The job was on!

Transportation:  The Clock Starts Ticking

Transportation was the first area to consider.  I decided this was outside my capabilities and renting appropriate equipment did not have a sufficient return as compared to hiring a trucking company.  I contacted a trucking company based on the seller’s recommendation to set up a delivery date.  From now on, I’m on a schedule and the plan needs to reflect this.

Rigging Day – ASAP: Ordering and Preparing the Equipment

With a delivery date set with the trucking company, everything from here out is on a timeline.   During my initial limitations assessment I determined my forklift was not sufficient to lift the machine.  However, a few quick phone calls located a 12,000 lb. forklift at a local forklift rental company.

Forklifts are rated by a combination of lifting capacity and load center.  During my inspection of the machine I roughly determined the center of gravity to be 24″ from the farthest protrustion on the operator’s side of the machine.  Adding 6″ to provide sufficient clearance results in a 30″ load center.  My forklift is rated for 8,000 lbs. at a 24″ load center, or 6,400 lbs. at 30″.  My forklift would tip over before the 8,000 lb. machine was off the trailer!  The forklift I settled on had a capacity of 9,600 lbs. at 30″ load center.  Capacity to spare is always a good thing!

In addition, I needed a rigging sling and pins to install in the rigging holes on the machine.  I decided on custom-made continuous synthetic slings and 4130 bar stock, both of which I ordered and received promptly.

Finally, I needed a way to move the machine once inside the shop.  During the initial limitations survey, I found a local rental house had toe jacks and machinery skates of sufficient capacity.  I reserved these well in advance.

Rigging Day – 2: The Machine is Picked Up

Two days before the rigging day the trucking company called to say the machine was on a truck and headed my way.  I confirmed the arrival date and time.  While it is a good idea to be prepared as far in advance as possible, I didn’t want to rent the equipment before the machine was on a truck.  As it turned out, this was good planning on my part.  The arrival date was pushed back three times due to trucks failing to pick up the machine at the warehouse.  Even after pickup, the delivering truck was delayed in travelling to my shop.

Move Day – 1  Prepare the Equipment and Shop

I scheduled the arrival of the toe jacks, machinery skates and forklift a full day in advance of the scheduled delivery date.  While this may seem like excessive, it is better to pay a little more than have the truck show up while you’re still waiting for equipment!

During this time I also prepared the shop by making a path for the new machine and doing general cleaning.

The forklift on the left is my 8,000 lb. machine.  The Yale on the right is the rented 12,000 lb. machine:

With all the equipment on-site and the shop ready, I made one final preparation.  Using the operating manual as a guide, I marked the forklift forks with a soapstone to show the maximum load center at which I could safely pick up the machine.  Running an unfamiliar machine I wanted to be sure I was within its capacity.

In part two I’ll cover rigging the machine and the after-action report.