Difference between revisions of "Base grinder"
|Line 45:||Line 45:|
Latest revision as of 22:28, 21 July 2011
I use a Fontaine 1404 base grinder, which was sold by Wintersteiger as model SNB 55. It uses belts that are 14” x 59”. The motor is a 4hp Leeson, and it has a little 240v water pump with an adjustable sprayer. It works just like any normal belt sander, with a drive wheel and a follower, and a knob to adjust the tracking. The drive wheel is a stiff rubber which will deform a bit and is good for finishing off boards with bases that are less than perfect. There is a platen that attaches over the center (optional on this machine) which is very flat side-to-side for getting bases true. There’s a cloth filter between the catch basin and the belt to keep metal and base material out of the pump.
There is no autofeed, though the machine was designed to have one added on.
There is no stock edge guide, but a buddy and I built a quick ghetto one out of some scrap aluminum. It’s ugly, but it allows me to hold the edge of the board perpendicular to the belt in an adjustable place, so I don’t wear out one line on a belt early.
I get all of my grinder supplies from SVST. The even have Fontaine replacement parts to fit my machine.
I usually use aluminum oxide or zircon belts. I use 80 grit to remove the excess epoxy from bases and to do a quick pass for the sidewalls. Then, I use 120 grit to finish. I keep a selection of old belts around for a final finishing pass since they’re not as sharp and tend to leave a nicer finish.
I use a “grinding coolant” in the water, sometimes called “cutting fluid” or “emulsion." The brand I use is Kool Kut Ski Grinding Coolant from SVST, which not only helps the belts cut better but also inhibits rust on the machine. It’s what makes the water look like antifreeze, but make no mistake: it is not antifreeze. The grinding coolant is pretty much non-toxic, which is very important because, no matter what, you will end up covered in a fine mist of it when you grind a board. The coolant I use seems to have no effect on me personally, though… I just keep it out of my eyes with some safety goggles, and wash up afterwards. It also appears to have no effect on my lawn. The MSDS on it is pretty harmless, suggesting mild irritation and little more.
The coolant is held in a simple plastic bin with a lid cut to allow room for the power and the supply line to the pump. This lets me mix up some coolant and keep it dust-free for a few weeks between grindings.
I do find that the coolant tends to grow mold if left for more than a couple of months, so I try not to leave coolant in the machine unless I believe I’m going to grind a board within a few weeks.
It’s very important to clean up a base grinder well after using it. You don’t want to leave the machine caked in base material fuzz and edge filings as it promotes rust on the machine. That’s what the standard garden hose nozzle is for: you can hose off the interior thoroughly, then use some shop towels to dry most of it off.
The machine draws approximately 21 starting amps at 240v so I have it on a 30A breaker. There should be a contactor or relay switch to turn it on and off attached to the unit, but it blew out long ago. I’ve wired it to be on all the time and I use the breaker as a switch. That’s why you see a small box on top of the motor with tape over it instead of a switch. I’ll get around to actually fixing it one day when it actually starts bugging me.