On Friday 08 April 2016 04:57:26 andy pugh wrote: > On 8 April 2016 at 04:44, Gene Heskett <[email protected]> wrote: > > It was the nut bracket that couples the Z sled with the Z nut. It > > has a couple cap screws that a 6mm Allen wrench fits, > > A 6mm key fits an M8 screw: > http://www.globalfastener.com/product/detail_2477.html > > As a sample, the front fork pinch bolt of my R1 is M8 into aluminium > and is tightened to 14 lb.ft. Having had a good friend killed by overtightening one of those, that may be correct, the clamp broke on a rough road and strained him thru a woven wire fence. But 14 lb/ft does seem loose to me.
> Some other M8 bolts on the bike are 20 lb.ft (also into aluminium). Thats more like it. But I'll have to fish my torque wrench out of the gun cabinet to get one thats accurate in that range. I have a 3/8 drive set of Allens in metric someplace in the shop building, so I believe I can do this right. But having been moving and wearing the the face of that alu part where it sits in a machined socket, I still think I ought to see if I can get some JBWeld in there to marry it better than by pure bolt tension. I just don't see how to do it w/o loosening the bearing anchoring screws at the top of the post. Getting that aligned in the initial assembly was a bear with 4 sore paws! Get it off 10 thou and it binds the screw at the top of the movement range. Originally the footprint of the nut holder was about 1/8" taller than the socket for it in the back of the sled, so I had to take it clear off the post, and use the toy mill to expand the socket by about .124" which made it a draw it into the recess with these 2 bolts interference fit. Now that fit is loose. That machining was visually leveled by setting the depth of cut to remove about equally, about 50% of any casting roughness, so I feel like it was right when I was done. Its likely I should adjust the upper soft limit, and possibly the homeing switch, downward to prevent its striking the top of the slot in the post casting to absolutly remove any possibility of its crashing into it. It has several times in the past when the motor lost steps pushing on a larger drill bit that was never sharp anyway. Question: Has anyone set a mill up using the home switch as a hard upper limit? It is in the correct position to do that, maybe 0.075" from the hard crash stop, but would need some hal trickery to AND2 that into the limit logic. There is of course only a soft limit for down limit, which it appears I should raise as the sled can crush the bellows mounting entirely too easily. But I am using a shared home switch scheme, so that would put a hard limit on one end of all linear axis's. Only on the X would that be a movement range limitation problem but I can adjust that easily since I'm using the OEM stops as switch actuators and they are adjustable. I'll drag out my .hal printout & see how to do that. If I do that, I'd assume the soft limits in that direction in the .ini file can/should be commented out? But right now, back to bed before I drink too much of this cold cup of coffee sitting here. I was up to recycle some of yesterdays & someone once told me that a good geek always checks is email before going back to bed. :) Thanks Andy. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
