Friday, August 7, 2015

One Month In - Precision

Over the last two weeks we went through the 20 Deere QA5 fairway cutting units, and we found all but one to be out of parallel by up to .120". (They are the early "pre-pinned" variety.) The average error was over .060", on a height setting of .350". That's 18% to over 30% error in the setup, which is orders of magnatude out of tolerance. With today's tools and techniques, there's no reason why a tolerance of +/- .002" can't be maintained (but getting there takes work - that's the rub).

Checking for parallel is a crucial step in the maintenance plan because cutting units tend to get knocked out of adjustment during use. When I first got here I didn't think there was a surface plate on site, but eventually found it behind an old tool box in the parts room. It's one of those aluminum plate jobs, with many rubber feet to support it off the bench top. Sweet. The first cutting unit I put on it had been paralleled on the Peerless 7000 grinder that Mark Pilger from SIP had brought in for the job. Clunk! Clunk! There was a significant "rock" - perhaps .030". I suspected the plate was bent, so I didn't readjust the rollers - I just set the plate aside until I got the new Starrett granite plate in.


Now that's more like it. It's a "B" grade stone, flat to within .0002" corner-to-corner. The flats are ground and hardened tool steel, .500" X 1-1/2" and .250" X 1". Total investment: a little over $3,000, which I feel is reasonable to have a reference standard we can rely on for assembling and inspecting cutting units which are expected to cut fine turf to below .100".

Oh, and the bargain aluminum job?


Yep; bent over .060", and destined for the recycling bin. Sometimes knowledge and skill can't make up for junk tools.

Fairway after cut appearance has been much better with the new setup, though we are still recovering from aerification on the Riverside course, so we have had to regrind those two sets twice this week. Hopefully the latest rains have washed the debris into the canopy so we cab focus on the next major task: greens reel replacements!

Regards,




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