Microstop Countersink

CFI1513840 · #1 06-29-2006, 02:00 PM

I am having difficulty getting repeatable results with the microstop, especially with the #40 countersink. I have two different microstops so the problem does not seem to be with the tool itself. What happens is after setting the correct depth on the microstop, with initial use in each hole the countersink will fall short of the preset depth, even with fairly heavy force applied, usually by only a small amount (a few thousandths of an inch). When this happens, I remove the tool from the work piece, clean all chips, etc, then retry. I find that after repeated retries, the tool will usually "bite" and the remaining material will be removed. I've tried using a new cutter and cutting oil, but the results are the same. I would appreciate any suggestions on how to improve this process.

RV_7A · #2 06-29-2006, 02:10 PM

Is this a used Microstop? I have one I bought on Ebay that does the same thing. Is obviously got some trash inside and cant be trusted !!!

-Jeff

szicree · #3 06-29-2006, 02:29 PM

It was a long while back, but in the early part of building I purchased the less expensive of two microstops from Avery (i think). After a while I started to get erratic results and dissassembled the tool to investigate. I found that that the bushing that serves as the internal stop was badly worn. I replaced the tool with the more "deluxe" model and problem was solved. YMMV.

fred · #4 06-29-2006, 03:58 PM

i had same problem a very long time ago with an avery micro stop. what finally worked was shelving the micro stop and just going by eye and feel this worked much better and easier. really not that hard to do and did have good results. flying 7A 190+ hours. fred

CFI1513840 · #5 06-29-2006, 04:48 PM

Thanks, I appreciate your responses. Both microstops I now have are the less expensive version from Avery. I've tried two different piloted countersink cutters as well and get the same results. I wondered if the cutter itself was causing the problem, but it sounds like it might be best to just buy the more expensive ball-bearing microstop.

William Slaughter · #6 06-30-2006, 05:45 PM

One thing that helped my results was going to a slow turning drill. I'm now using an old 7.2v Makita that runs about 600-700 rpm, and am having much better luck. I don't know if it's the cutting action of the countersink itself, or it's just easier on the microstop cage to not have to turn so fast, but it sure works better. I can't remember what the pedigree is on my microstop.