#31
|
|||
|
|||
as for the string comment - I walked right into that one
After a long run last night, Ted thinks the screws have backed up... When I disassembled it yesterday, the screws had not backed up/out. Gerald, your last comment has me thinking that the back/forth action on the z (we are doing a lot of 3d, especially z) is causing the shaft to "wallow out" where the screw contacts the shaft. I have seen/heard people relief drilling into the shaft before the set screw to give the set screw a bit of a shoulder to work on. As for loctite, I've got some red (aka permanent or bearing mount). BTW, this is on the larger gear (72 teeth) of the belt transmission. The pinion is holding solid. This gear is also Aluminum though we have a steel gear in our stash. Back to the length of string is that before/after knots and twists? Besides string is either too long or too short, it is never just right. That is why we have teeth. (Just made Ted aka Crashingsucks crazy on that one.... ) |
#32
|
|||
|
|||
Sorry, couldn't resist the string snark
If the metal/metal contact is "wallowing out", it can only help if you double the number of those interfaces.....a second screw hole. A pre-machined hollow wouldn't be as good as a a hollow worn in by the screw itself. A couple of re-tightens in the early days should get the screw/s nicely bedded. Then add loctite. |
#33
|
|||
|
|||
Yeah it is better to pull the string than push it!
I can see the point there on just letting it wobble a bit and retighten (using new screws). BTW, we already have two screws 90 degrees apart |
#34
|
|||
|
|||
Aha!
This is where my cunning stunt of cutting the grub screws down and having a flat surface pressing against the flat on the shaft comes into play. *cough* |
#35
|
|||
|
|||
Very educational thread.
John, I'll store your trick for later use. |
#36
|
|||
|
|||
You might want to wait until I try it out in anger so far it's all theoretical until the pinions get a hard workout
|
#37
|
|||
|
|||
on and similar but different wavelength (figure that one out guys.... )..
I fly R/C aircraft and we use a collar arrangement to keep (or at least supposed to keep) the wheels attached to the wire landing gear. Think small wire (0.125 or so) with brass collars and a single set screw (smaller than #2). Well a buddy and I got tired of his wheels coming off (due to collar falling off).... So.. I took a collar rethreaded with a 4-40 and used an alloy/hardened socket head machine screw that I had cut off... Similar to JWT's thoughts.... different application... but it might work. Especially if we ruin another $400 part. But we are running even as I write this so I know more in about an hour.... stan |
#38
|
|||
|
|||
Just got back from the shop. Recut of the mold.... Wait for it....
V V V V PERFECT! Better than what the guy was getting from another guy running a ****bot Just got to keep an eye on the set screws before running a 6.5 hour finishing pass. |
#39
|
|||
|
|||
Quote:
|
#40
|
|||
|
|||
One of the main reasons why I went the MM route. Before the MM, I asked for and received samples of what other machines could cut. I was amazed how bad the cut quality was. And, that a company would send out something of such poor quality. Bad for them, good for me.
|
#41
|
|||
|
|||
I get better cut quality than a large number of CNC machines manufactured in Taiwan in the $15,000 to $20,000 US dollar range. Of course the $50K to $100K Big Iron machines cut about the same as the Mechmate. I've seen a number of big iron machines around here sporting a lot of bells and whistles like massive servos and 55mm lead screws, but I'll have to say that I'm really not jealous. I've even seen 5X10 machines go from x and y extremes to home in under 3 seconds (Yes, I've see a few that could actually pull that off and it is really impressive) but, can you really cut at that speed? No!!!
|
#42
|
|||
|
|||
Yeah, I mean come on folks... Why pay that when for less than $5-6K one can get this quality of cut....
Our silent partner in the process uttered a quiet "wow," when he saw the mold... He's pretty hard to impress.... |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
mechmate.com search - SOLVED !!! | rotorzoomer | Miscellaneous / General / Whatever / Catchall | 4 | Mon 17 May 2010 17:00 |
Pinion gear chatter | lunaj76 | Driving Mechanisms: Rack/pinion, gears, screws, belts & chains | 5 | Tue 27 October 2009 01:29 |
Inconsistent accuracy - loose pinion gear | bfauska | Troubleshooting | 11 | Sat 05 September 2009 09:05 |
Screw threads - inch & millimeter | Gerald D | Golden Resources | 1 | Mon 09 March 2009 00:54 |
Circles are not cut round - loose pinion gears | sailfl | Troubleshooting | 21 | Sun 15 February 2009 17:19 |