We recently received a comment on one of our early tips by tom articles. This article on aluminum cutting seems to get a lot of traffic. It was one of our original posts and contains helpful information on cutting aluminum in a pinch. The article explains how you can use equipment found in any wood shop to accomplish the job of cutting aluminum. At any rate, after several years we received this letter from Don in Florida. Since we are into entrepreneurship, we thought wed go ahead and post! Thanks for noticing our website Don and best of luck with your business!

Hi Tom,

My name is Don McKinney. Our company is Bob’s Saw Sharpening, Inc. I
read your article on cutting aluminum and liked the warning about the
“kick back” . Many people don not realize that when using the wrong
tool for the job could be very dangerous. The kick back comes from
using saw blades designed to cut wood or an improperly designed aluminum
cutting saw. We manufacture a line of blades for this material that
does NOT kick back or grab. Leaving a bur free cut on most shapes
including plate, pipe, window and store front extrusions, picture frames
and even PVC. It’s called the NO-GRAB. It has more of a milling action
than a cutting one. With a wood blade, the more you feed, the faster it
cuts. Our blades offers a controlled chip. The more you feed, it
doesn’t cut any faster!

If your interested, contact me at 1-800-359-2887
Don McKinney
President
Bob’s Saw Sharpening, Inc.
721 N.W. 7th. Ave.
Ft. Lauderdale, Fl. 33311

Tom had the opportunity to work on a turbo piston several weeks ago. On this particular piston the compression ratio needed to be lowered. Pistons are a basic part to all types of machinery that employ a reciprocating engine and are designed to work in harmony with the other components of the engine. Pistons sit in a cylinder and operate by transferring force to the crankshaft. If you have ever wondered why the tops of the pistons have an elevated ring around them, here is the answer.
The outside area of a piston is called the quench area. When machining a piston you need to be careful not to take to much of that outside area out. When the piston is in motion and going up under compression the quench area comes very close to the head and transfers a small amount of the heat out of the piston into the head in a matter of a split second. If the quench area has been machined down too much, it can cause the piston to over heat. This could lead to detonation. Sometimes this is the cause of an engine that has over heated.

New Shock Sleeve.

Tom got a bike in the machine shop with a broken upper shock mount. The owner of the mountain bike wasn’t able to get parts for the bike, so he brought the bike to Tom to see if there might be a way to fix it.
The bushing that was in the shock was wore out. Tom pushed out the bushing. He fabricated a new sleeve that would span the two suspension arms using O1 drill stock with a ground finish.
O1 drill stock is a oil harden drill stock and has a good rock well hardness.
Tom turned the OD and then drilled out the inside diameter to eight millimeters, so the eight millimeter bolt would fit through the two suspension arms. The metal sleeve is designed to span the distance between the space of the two arms and helps reinforce the bolt. The bolt fits into the middle of the sleeve. Tom fashioned two small snap ring grooves to keep the shock centered. The original design had two additional sleeves on the outside of the original sleeve. Tom eliminated the additional sleeves by using snap rings on each side of the shock. It should be a better fix than the factory sleeve which consisted of a thin sleeve over the bolt and aluminum outer sleeves.

Laramie Wyoming is a great place to mountain bike. There are several areas just a short drive from town. Fifteen minutes east on I-80 will land any mountain bike enthusiast in the Happy Jack Recreation Area where there are a variety of trails at several skill levels. The Vedauwoo Area is not much further and boasts beautiful rock scenery. Going west out of Laramie leads one to the Snowy Range. There are many trail heads for hiking and biking in the Medicine Bow National Forest. If you are looking for a more adventerous trip, you might try booking a luxury bike tour in France and Europe by visiting Bike Tours Europe.

Piston on Milling Machine

A piston from a turbo charged engine came into the machine shop that needed the compression ratio lowered. The customer could no longer find pistons that were dished with a lower compression ratio. The turbo pistons brought in needed to be dished 10 CC’s.
The first step was to do the math to find out how much material Tom should remove from the piston using a radius end mill and rotary table. Tom knew he would want to take out about 3 inches in diameter from the metal piston. He then converted 3 inches into centimeters. Then he did the reverse of “Pie R Squared” equals the area. Then he was left with the diameter. The end result was fifty thousandths that would need to be removed from the center of the turbo piston.
After milling out the center, Tom wanted to double check the results.
Tom used a CC Kit to measure the milled out space. A CC Kit includes a small piece of plexiglass, with a tiny hole in it, and a measuring beaker.
The first step is to seal the piston with grease and set the plexiglass on top. Next, fill the beaker to the top measuring line. Then carefully release water into the area that has been milled while holding plexiglass in place.
The beaker measurements told Tom how much volume was milled out of the piston dish.
A CC Kit can be used on pistons and heads to establish an accurate measurement.

In this job the cast iron steering shaft support was worn egg shaped and the steering shaft was worn down on the outside diameter. The first step in the repair was to machine a round hole where the egg shaped hole was located in the cast iron steering support. I accomplished this by using a adjustable hand reamer, by using the hand reamer the original angle that the shaft went through the cast iron support is obtained. I would have liked to use a boring head to correct the egg shaped hole, but the shaft and support were all I had to work with to keep the correct angle.

 A hand reamer with care will normally follow the original hole. Once the support was reamed I had a diameter to work with.

It would make sense to make a brass bushing for the support at this time but the steering shaft is also worn.  The steering shaft from this John Deere tractor is the same diameter along the shaft except for the worn area, so a bushing would not slide over the good portion of the shaft.  

The shaft was sand blasted at the worn section to help in the brazing process. The shaft was then brazed up with enough brass to turn in the lathe to clean-up at the desired out side diameter.

After turning the John Deere steering shaft to the correct outside diameter, to have a nice slip fit into the cast iron support, the tractor should be ready for the parade…. With a little bit of paint and new rubber.

The brazed portion of the steering shaft will wear more quickly than the cast iron support making the repair easier and cheaper forty years from now.