Sunday, March 24, 2013

Automation and a Dodgy Left Shoulder

When I was a younger man I did not own industrial quality machines and I was prone to wearing out parts on the machines I used in my work. These days I'm older, yet I have industrial quality machines and now I'm wearing out parts on myself.

When I first began this blog I posted about the acquisition of a 1959 Covel #10 surface grinder. The old grinder has been a great machine. The cost associated with purchasing, moving the machine, and upgrading this machine are to a point where I really have more invested in the machine than it's relative market value. However as a result of this investment I know what I have,  a machine that grinds accurately and flat over the length of it's capacity which is always a question mark with any used surface grinder.

However the Covel came as a manual grinder which means all the moving parts have to be activated and run with physical action on the part of a human operator and the worst of these activities is traversing the table left to right constantly. This requires many repetitions just to grind the surfaces of one part. This finally took a toll on my left shoulder. One Friday morning  several weeks ago I began experiencing a stabbing pain under my left shoulder blade. I figured a bit of rest and some over the counter pain medications would fix such luck. In fact things got worse and it became evident that I would not be doing any grinding for while. I needed to give my shoulder time to heal.

Being persistent I starting teaching myself how to grind with my right arm only. I could do this but it was a slow process, futile really. I decided that while my shoulder was recuperating that maybe it was time to shop for an automatic surface grinder. A quick bit of research revealed that an automatic surface grinder with any chance of reliability was going to cost something close to automobile purchase type money.

Given the time commitment required to move one machine out and another machine in, and considering the investment I had in the Covel grinder I decided it might be worth an attempt at automating the Covel.

I read on many of the online metal working forums a lot of speculation about how one would go about automating the long axis of a surface grinder, however there was no documentation from anyone that had actually pursued and accomplish this to any degree of reasonable use so I contacted an automation company and proposed my plan for accomplishing this task and ask them if they thought it was a feasible idea.

They agreed that it was feasible, recommended a few changes to my plan and also informed me of other information I needed to gather in order to make reasonably informed decisions as to what components would need to specified and purchased. It seemed my gamble was going to cost somewhere around $1000.00 and there was no guarantee of success. Considering the price of an automatic grinder or worse yet, a new shoulder, I decided I would take the gamble and began the research required to fill in the blanks of how to undertake this transformation. The picture below shows all the major components required.

A 1/2hp  3 phase inverter rated induction motor, a 40 to 1 gear box (speed reducer), GS2 Variable Frequency Drive, not shown are the miscellaneous wiring devices, various pulleys and belt required.

The motor control configuration was sorted out after a study of the VFD manual....actually an extensive study. I have two other 3 phase motors in my shop powered by VFDs, however I would be asking this one to perform more complex motor control than anything required on the other machines. The picture below shows all the components mounted to the machine and also a belt/pulley guard fabricated for safety sake.

Basically everything operated as expected even though some parts of the system did in fact require considerable tweaking along with some tweaks to the vfd programming. Check out the video below of the newly automated grinder actually working.

Much to the relief of my left shoulder the automation of the surface grinder tables works great and operates very reliably. My gamble paid off. Now to get busy and make up for lost time.


Wednesday, March 13, 2013

Julie's Porch Part 5, Phase 1 Complete

Roofing the porch was a pretty typical shingle roofing job. I was lucky when all the shingles were in place and it was time to bridge the gap from the house roof to the porch roof. A piece of standard z flashing went under the house shingles on top of the drip edge and popped right into place with the wide flange tightly against the top of the last course of porch shingles. All that was required was a bead of roofing cement under the flashing and some evenly spaced nails to hold it in place.

Now that all the roofing components were in place it was time to protect everything from the elements. Two coats of an oil based primer and 2 coats of a quality exterior latex paint tied everything together visually.

We started this project in the fall and by the time we were at this point in the process the holiday season was approaching. We took a hiatus from the porch project so that I could concentrate solely on plane making.

 After the first of the year we turned our attention to the porch floor. Unfortunately I suffered a shoulder injury before we could install the flooring. No dramatic event caused the injury. It was due to overuse of that part of my body cause by the repetitive traversing of the table on my surface grinder. There was no way I could install the flooring until my shoulder had healed, however we needed to get this project completed so that when spring rolled around we could turn our attention to Phase 2 of this project, installing the screening.

Enter my good friend Jon Fiant. (pictured below)

 Some of you know Jon Fiant as a woodworker that has lately made the making of workbenches a large part of his focus.  The picture below is one of Jon's workbench creations utilizing BenchCrafted vises and Shaker Bench design.

I asked Jon to help me out with the flooring installation and to my delight Jon spent 2 days making an excellent job of laying the tongue and groove flooring, attaching it to the subfloor with stainless steel screws and leaving a precise spacing between each of the boards. Two coats of exterior stain later and Phase one of Julie's Porch was complete.

Looks inviting doesn't it? My son in law has begun calling this our sipping porch. Paul knows a good sipping porch when he sees one. We also do some rocking, some gliding and.....just sitting on this porch as well.

What do we sip? Well I'll leave that to your imagination.