Chris Larson

OpenOPC and Python Tutorial

Submitted by Chris Larson on Sun, 05/13/2012 - 22:28

My boss gave me a challenge to create a simulation for the field devices our PLC will be talking to. We need to simulate the devices for the factory acceptance testing. Originally I though I would use C#, but ran into a pay wall with the OPC Foundation. They want $15,000 before I can download the source code. A lesser entry fee will get me some of the wrappers, but since I can't see the documentation before I pay I don't know if the wrappers will be sufficient. That price was ok before the connected world, but now community supported projects need to be open and collaborative.

Started a new blog called Table Sawin'

Submitted by Chris Larson on Thu, 05/03/2012 - 14:24

I purchased a used table saw two weekends ago and decided to start blogging about it. At first I added a tab to this blog, but since table saws aren't techy or computer related it seemed more appropriate to start a separate blog. A quick search on namecheap revealed there were squatters on all the base names like tablesaw.com. I am disappointed by this because it is such a good name and for 14 years the squatter hasn't done anything with it.

New Blog TableSaw.in

I started a new blog Table Sawin', where you will find information about setting up and maintaining a table saw. Originally I had planned to make it part of my site here, but I thought I would try blogger and see how it rates. Using the blogger platform will simply the webmaster activities I need to perform and also make sure there is ample bandwidth for the site during peak times. The plan is to use all google and free tools for the Table Sawin' site.

Cleaning the table insert

The first time I removed the table insert it stuck and I had to gently tap it out. Before putting it back I cleaned the edges and scraped off the paint and caked on saw dust that had accumulated. Again I had a tool for cleaning and removing gaskets that worked perfectly. A slightly dull knife would just as well. The key is to not nick the edges of the cast iron table top.

Checking the Pulley

I checked the roundness of the pulley by sighting cross axis and watching the profile relative to an object further behind. Any movement indicates there is a problem. I use two methods to confirm that it is the pulley and not me being unsteady. The first is to rotate the shaft slowly while watching the profile to see if it wanders. The second is to spin the shaft quickly and note the sharpness of the edge. If the edge becomes fuzzy that means the profile is not staying in the same spot.

Pulley

The pulley on the blade side appeared to be out of round. While turning it slowly I could see the profile wandering. My suspicions were further confirmed when I turned the saw on and watched the belt bounce and shake the whole table saw. After a quick search on Amazon I found a replacement of the same dimensions and material and ordered it. At the same time I also ordered a new belt. The damage was less than twenty-five dollars with shipping.

The Main Bearing

After I removed the blade I took the opportunity to check how true the main bearing was. Even after so many years there is no looseness or grinding. Since these bearings are sealed there isn't much I can do as far as maintenance. The threads are solid and without nicks.

How to remove the table saw blade

Removing the blade on a table saw is one of the most routine actions I perform during a project. It is important to use the correct blade for the task. If I am cross cutting, ripping or using the dado I make sure the correct blade is installed and adjusted.

First unplug the table saw and make sure you can see the plug while you work.
Second remove the table top cover that surrounds the blade and prevents small pieces from falling through the table.

The One Table Saw Rule: Only wood goes on the table top!

Unfortunately not everyone follows the rule that only boards to be cut go on the table saw surface. The table saw I purchased has clearly been used as a coffee table coaster and painter's booth. The beverages must not have sat for long because the rust is only surface deep and will polish out with some steal wool. The paint and glue stains will need to be scraped with a soft metal tool. In my tool set I have a tool that looks like a wide headed flat screw driver. I picked it up at Sears for scraping away the remainder of a head gasket.

Craigslist Powermatic Table Saw

Purchased my first table saw. When I left Minnesota the table saw stayed in my dad's garage, it is his after all. After three months of living in an old house I reached the breaking point and started searching for table saws on craigslist. Many of the saws listed were cheap aluminium contractor saws. The contractor saw is great for trimming siding and fences, but can't keep an edge straight enough for furniture. I need a solid table saw, but at the same time I can't justify spending the five thousand or more dollars required for a furniture grade saw.