When I moved the live center closer by one pin hole, the live center could not be retracted back enough to get the stock in place. Nor was it possible to move the live center back a pin hole, insert the stock, then “push” the live center forward into the stock until the closer pin hole clicked into place. There is no leverage to do that because the live center, being unlocked, simply slides back to the farther pin holes and you’re back to condition 1. There seems to be a design gap in the spacing of the linear rail pin holes.
This is solvable, just a bit more work for the user. I had to drill a V divot into the tail stock to allow more room for the live center to be moved into place after I had inserted the stock into the chuck.
Wood was easy to resolve. Aluminum would have been a bigger pain to drill the divot. If anyone else has had this issue come up, hopefully Avid will update their pin spacing design for future purchasers.
File this as a ‘hack’ rather than a solution to your problem: Use more than one live center. It will almost certainly have a different length, so the gap will no longer exist. It’s a 2MT taper.
Actually, the whole tailstock is a bit of a disappointment compared to the rest of the overall rotary kit (which I think is great). I’ll likely use my Robust live center (shown below). The handwheel has to go too.
I reported this well over a year ago
I then did the “hack” and just used 2 different live centers.
I was then having problems with inconstant parts. I did find out that with the center extend it just was not stable.
So I bought a 2nd center. Now I never extend the center that is holding the part I am running and use the 2nd center to just push the front center into the part.
I have found That I now get constancy in the parts off of the rotary.
Yikes! That’s scary.
So if I’m understanding this correctly the problem you found was the combination of the live center and extended quill barrel gave you unacceptable deviation. Is that right?
Do both of your tailstocks behave in the same unacceptable way? It makes me wonder if the point of the extended live center is off axis. Or is there flex?
I never noticed that before. I just went and measured mine and the usable stroke of the tail stock is only 2", but the stop spacing is 2.38". That is definitely a design error. The spacing needs to be less than the travel to guarantee it will always reach.
Let me add this question to the mix:
Has anyone tried - and been successful - with re-greasing the rolling bearings underneath the live center plate? I tried with a normal grease gun (essentially identical to the one Avid supplied) but the grease gun’s tip just cannot quite get underneath the plate to push in the rolling bearing’s grease button. Things seem to be just a hair too tight. Perhaps I’m not on the right angle, but I tried multiple angles with the grease gun. Perhaps it’s because I cannot position myself underneath the rotary table as I have a sawdust basin in place. I have to attack the grease bearings from above the table. Anyone else have this problem or have people simply not greased their bearings ever again?
Matt
I know that this is an older thread, but you can get a longer tip for the grease gun. I just got one from Amazon that is 1.5 inches long, and replaced the .5 inch long tip that comes with the grease gun with it. It works like a charm.
After working around this for a year I decided to make a permanent solution. Restating the problem, pin spacing is 60mm and the quill can travel 45mm. So there is a dead zone where the tailstock won’t reach.
My solution was to redesign the plate with two sets of locking spring plungers. These are spaced 90mm apart. The difference between the pin spacing and the plunger spacing is 30mm, half the pin spacing. If the position using the rear pins doesn’t work, the front plunger will fit in a different pair of pins to give the right spacing.
Admittedly this is a bit of overkill, but the project served a dual role as my first time machining aluminum. That was a lot easier than I thought it would be. Things machined well on the Avid. I’ll just have to deal with cleaning up odd bits of aluminum swarf the rest of my life.
Thanks for the pointer on the knob. Im going to get one of those. I need to take mine apart and see why its so sticky too. Don’t know if it jas bad threads or what, but it always had a sticky point on half the rotation
I noticed this dead zone on my rotary as well. I haven’t really used it yet other that testing to see if it worked, but the first piece I stuck between centers didn’t work. I like the added plunger idea.
Nice job on the dual spring plungers. I realized later that this would be the proper solution but I have never fixed mine yet. I purchased a different live center (with a different length) based on your earlier post, so if the Avid live center hit the dead spot, swapping the live centers (and maybe moving the plate) should be able to hit all locations.
Thanks Matt!
This works a lot better. I have a ‘favorite’ live center and now I can use that all the time without worrying about fit around the dead zone.
Note that this is an entire fabrication from another piece of aluminum plate. I’m pretty sure it wouldn’t be possible to ‘fix’ the plate that comes with the rotary kit. The two issues are the physical size of the tailstock plate (not wide enough), and one needs to work around the width of the bearing blocks (77mm) and the dimensions of the 12mm jam nuts.
I use ‘stock’ CNC12 and have my own calibration process using a KP-3 touch probe, so I don’t really have a use for Avid’s touch plate. My Fusion drawings have the touch plate hole positions on them so someone could mount a plate if they wanted to. PM me if you want the Fusion file.
Scott
