En garde!: from WoodCentral
“I was just told by OSHA that I need a guard for my drill press. The good news is that I can build my own; the bad news is I have no real ideas that seem to work. Anyone have any ideas they would be willing to share? Thanks.” – Kai
“I can’t imagine what a drill press guard looks like. I don’t think I’ve ever seen one on any of many drill presses I’ve seen.” – Randy
“What are you guarding against? Covering the belts? Keeping your hands, head or hair out of the spinning bit? A little more detail would help us all offer conflicting advice.” – Bill
As asked, Kai came back with more specifics. – Editor
“To be a little more specific, I need a guard to cover the chuck and the bit. Apparently someone in Nevada lost a finger to a spinning chuck and several people have had hair torn out. Makes me wonder if any of them actually read the manual for the press. I have found several aftermarket guards, but $100 or more seems a bit much for what I'm seeing. I am trying to get clarification on if it needs to go completely around the chuck or if it can just be in front where the operator stands.” – Kai
“A lot of the time what will be approved is what the individual inspector had in mind. Our small drill presses have only a chip shield that does not even cover the chuck. They do make better telescoping
shields now, but for our work they were not practical due to the shapes being drilled.” – Galen
“I have a drill press with a chuck guard fitted on it. It is a spring-actuated flip-up, semi-circular, Perspex guard, which is fitted around the boss or ring above where the chuck slides into, on the drill body. The idea is that it can be easily flipped down to cover the revolving chuck, thus avoiding the dangers that others have mentioned. When I first bought the drill press, I used it a lot. It is easy to flip down but over time, the Perspex has gradually gone cloudy, making it nearly impossible to see through it. So now it gets left in the upright position. In use, I have found that it is not necessary while drilling wood, as the shavings thrown out break off at the drill bit causing no harm. But, as I'm sure most of you have found, drilling metal is quite different. Long strands of hot metal spin off about the bit, making safety glasses or a guard a sensible precaution.” – Hamish
Simple Solvents: from WoodCentral
“In the past I have used varnish, boiled linseed oil and turpentine. I see where a lot of people use mineral spirits in place of turpentine. I am wondering just how this affects the finish. It seems to me that it would dry faster and perhaps smell less.” – Bill
“Turpentine is distilled resin. As such it contains mostly terpene derivatives, alpha-pinene, limonene, beta-pinene and camphene. These are small molecules with one or more double bonds and usually a pleasant aroma. They are often cyclic. C10 is the typical carbon number. Mineral spirits are a mixture of aliphatic straight chain hydrocarbons (C7 to C12) with some cyclic aromatics and cyclic compounds mixed in. The distillation range is much broader.” – JL
While that was a good chemical description, the writer may have been hoping for a simpler answer. – Editor
“In my experience it makes no difference since either eventually evaporates and essentially is a solvent or thinner for the other two components. Usually, mineral spirits is cheaper, although turpentine smells better to me.” – Bob
“I think the difference is the smell. I prefer the smell of turpentine.” – BilWil
A couple of more complex answers followed. – Editor
“There are a number of thinners that can be used to thin an oil-based paint or finish. Turpentine is a natural product that has been used for years. It is made from the sap of pine trees. There is no standard for what turpentine consists of and it can be somewhat variable in performance. It has a strong, long-lasting distinctive odor. Naphtha and mineral spirits are the two most common solvents. As far as volatility (speed of evaporation), naphtha will flash off the fastest. The petroleum thinners are much less variable than turpentine. Finally, oil-based finishes dry and cure in two steps. First the thinner and solvents evaporate and the finish feels dry to the touch (tack-free). However, the next step is the actual curing of the finish. The cure occurs as oxygen mixes with the varnish and the varnish changes composition into a hard and strongly adhering film. This curing process takes three to four weeks to be completed. The point of this is that the choice of thinner only affects the initial evaporative step. It has no effect on the speed of the curing process.” – Howard
Eventually, someone summed it all up, with some corrections. – Editor
“As was mentioned, turpentine is a natural product derived from plants. As such, it contains more components and varies more than petroleum-based derivatives such as naphtha, mineral spirits and deodorized mineral spirits, all of which are specifically crafted by us to be more consistent than that which is crafted by nature. Naphtha, minerals spirits (also called paint thinner) and deodorized mineral spirits are basically the same soup of primarily alkanes or paraffins. If this soup has a flash point below 100 degrees F, it is called naphtha. If above, it is called mineral spirits or paint thinner, two terms used interchangeably by the industry. Lower flash point means faster evaporation, so yes, naphtha evaporates faster than the other thinners. Deodorized mineral spirits, also called Stoddard solvent, is a soup like the others, but one that contains almost exclusively isoparaffins, a group of alkanes that tends to smell less. There are many different formulas for these soups depending on what they are to solvate and how fast one wants them to dry. Finish formulators can choose from a wide variety based on these characteristics, but if you buy it in paint or home stores, you are limited to what the manufacturer decides to offer in those venues. Thus, other than the fact that naphtha is the fastest, the others may vary widely in speed depending on the formulation. As was said, all can be used to thin most oil-based finishes. Perhaps most important is what Howard said; solvent evaporation is only the first step in a two-step curing process. Which solvent you use will not affect the film you eventually get once it is cured by oxygen polymerization, the means by which oils cure.” – Michael