Reprinted with permission from SurfPrep website.
Stop! Don’t buy that wide belt sander!
This is a very difficult article to write without making some folks angry and some absolutely irate.
Machinery salesmen have a vested interest in selling the machines they have on the floor instead of the machine the customer needs. What is worse is that those same people often do not really understand the essence of sanding and how to optimize it for the customer. They need you to be happy enough to make the final payment and then they are pretty out of the equation.
Customers buying sanding machines are very rarely sanding experts. I have personally witnessed a plant manager at a very large company raving about how wonderful his very expensive wide belt machine was while I was watching his operator pushing parts through with a stick. He blamed the operator for every single difficulty with the day to day operation of the machine, even though there were huge design flaws in the machine that were actually responsible. The operator doesn’t know he shouldn’t have to use a long stick to push parts through so he doesn’t argue about it too much. He doesn’t know the design flaws contribute to constant quality problems. Meanwhile the company plans to buy another machine with the same flaws and issues.
Several years ago I worked on a tiny little SCM Sandya 2 Head for a customer in Central Indiana. This is a very respectable little machine with a steel drum and a combination head in the second position. They were running 100 and 150 cloth belts on close to 1,000 parts of various sizes per day. They sanded cabinet doors, frames, and all the associated parts. They used up those two belts every day.
The owner of the company asked me to help him pick out a larger used machine. He wanted to shop around the various websites and find 3 Head machines that looked like they would serve his purposes. My response was to tell him he should really look at a new machine from a particular company that sold a great quality machine with very particular traits. The machine should have dead shafts, air exclusion (pop the heads up/down with the flip of a switch), and it should be a steel drum-60 shore drum-combi-head with a 36 shore drum and bladder platen. I told him this machine would run 80-120-180 extremely well and his belt life would be unbelievable. He said no way could he afford to buy a new machine. He decides to just run the machines by me for approval...
Week after week he calls to tell me about different machines and asking me my opinion.
Him- “I found a completely rebuilt ___________!”
Me- “what color is it?”
Him- “What? You can reject it because of the color!”
Me- “Is it a 75 shore drum, 55 shore drum, platen with a relieving table?”
Me- “No. The 75 shore drum isn’t hard enough, the 55 is too hard, and the relieving table machine shoes are a joke. The beds don’t hold calibration. Live shafts are not as rigid as dead.
What he did not understand is that the configuration of the machine in question was a mild improvement over his two head. It could only run 100, 150, 180 really well and still keep up with his stock removal requirements of .020” per side. You should not skip a grit going into a platen from a drum. Miss match in the frames would max out the sequence in various spots. The belt life would be at least 3-4 times longer than the 2 Head. The scratch pattern would be okay but nothing extraordinary. I have worked on hundreds of these machines so I know them like the back of my well scared hands.
We did this for weeks with machines from various companies and configurations. One day he called and I rejected the machine again for the last time. He got angry with me and said, “You won’t let me buy any machine but the one you told me to in the first place!” “I just want you to be happy” I told him.
He called the guy I knew at the machine company and told him to call me to find out what he needed. The machine company guy calls me laughing because the customer was extremely annoyed…. I told him to run steel, 60 shore, 36 shore, bladder platen, 80/120/180 paper belts, and exactly how much to take off each head. The 120 had to remove .008” to get rid of the 80 grit scratch and the drum on the combi-head needed to remove .004”. The platen was to remove .001”. The machine had to be ordered so it took a few months to come in.
After the machine ran a month the customer calls me on the phone.
Him- “When do I change the belts?”
Me- “Are you on the same set?”
Me- “Do you see any problems with the scratch? Polishing? Lines?”
Him- “No. It’s perfect.”
Me- “Keep running.”
He calls me a month later.
Him- “I just changed the belts.”
Him- “Because, you can’t run 3 belts for two months. It’s impossible.”
Me- “You just did.”
Him- “I know. It still looked great too.”
His first set of belts ran for approximately 40 working days. That is right around 40,000 pieces through the machine. I told him to change the belts every month to maintain consistency and not have to worry about polishing. Yes, you read that right. No, I’m not kidding.
He might have been paying around $40 for those cloth 36” x 60” belts. He was paying around $50 for the paper wide belts. $40 x 40 belts a month is $1600. $50 x 3 is $150 for the 53” x 86” belts in the new machine. 13 times less belts. Do you think that paid for the machine payment? The rebuilt used machine might have taken the belt usage down to $800 a month or better, but the configuration was the limiting factor. It could not produce the quality of scratch over time that the new machine could. This X factor cannot be easily calculated.
The reason one configuration was better than another is the subject of some of my other articles. I could write books on this subject. I tell this story a lot in my travels. It is a great illustration of how much money you can leave on the table if you make poor choices. I feel so helpless seeing so many customers snatching defeat out of the jaws of victory! I recently told a customer that if their machine had a 4th head the difference in configuration would have saved so much money in abrasives it would pay for the machine they had every couple of years for the life of the machine.
Please educate yourself before you sign on the dotted line. I can’t bear to see another customer suffering a crappy machine and losing money in the process. Base your decisions on real costs and savings rather than the lowest prices and what is sitting on the show room floor.