Deckel FP2 how to free frozen horizontal quill? - Page 6
Close
Login to Your Account
Page 6 of 6 FirstFirst ... 456
Results 101 to 111 of 111
  1. #101
    Join Date
    Mar 2015
    Country
    GREECE
    Posts
    514
    Post Thanks / Like
    Likes (Given)
    139
    Likes (Received)
    121

    Default

    Quote Originally Posted by sigurasg View Post
    I just got the braking resistor and I wasted no time in hooking it up and testing it. I think I might be coming to a realization that it's perhaps not worth much to brake a mill with a VFD.
    Now, the VFD ramps down the output frequency at a fixed rate until it gets to a cutoff frequency. The cutoff frequency is 3Hz by default, I believe, and after that it can additionally "DC brake" for a set time - which I'm weary of.

    If there's a lot of angular momentum in the system, like the spindle is running at 2K RPM, the motor doesn't have the torque to brake it very quickly. The end result of e.g. a 1 second ramp-down is that the spindle slows down maybe half way then coasts from there. If I set a longer ramp-down time, the spindle will slow down further (100RPM for 3Hz at the 2000RPM setting).

    If, however, the spindle is moving quite slowly (as would be the case when power tapping) the ramp-down probably takes longer than coasting to a stop would.

    My Chinesium lathe has a foot brake which I use quite a lot. It's mostly a convenience to slow the spindle down quickly before taking a measurement or to change the tool. It's also, however, a safety mechanism when e.g. I get a rats nest tangle around the chuck, I can just stomp on the brake and bring the mess to a very quick stop.

    Anyhow, I'm wondering whether spindle braking a mill is worth the trouble at all. I guess I'll have to play with this while using the mill in anger, but I'd love to hear your opinions and experiences.
    Spindle brake can be helpful in cases of needing to stop and measure, or reposition a collet block and the like. Simple things but some times you don't have the patience to wait a bit for the spindle to stop before doing something, especially if it's repetitive.

    Ross has done a crazy modification on his FP2, adding a brake drum, operated by the rapid lever, only towards the other direction.... I bet the pics were stored in photobucket which is a real pity....

  2. Likes sigurasg liked this post
  3. #102
    Join Date
    Sep 2011
    Country
    GERMANY
    Posts
    2,655
    Post Thanks / Like
    Likes (Given)
    1644
    Likes (Received)
    936

    Default

    Quote Originally Posted by thanvg View Post
    Ross has done a crazy modification on his FP2, adding a brake drum, operated by the rapid lever, only towards the other direction.... I bet the pics were stored in photobucket which is a real pity.
    Ross, if you see this and still have the pictures handy, please repost them. I think this is one of the best examples I have seen of extensive machine modifications and improvements which (a) matched the spirit/character of the original machine and (b) matched the quality of the original construction. I don't want to make you blush, but frankly it's inspiring.

    [EDIT]

    I found Ross's thread, reposted a couple of years ago, with all the photos intact:
    https://www.practicalmachinist.com/v...e-brake-342223
    Last edited by ballen; 11-08-2019 at 04:58 PM.

  4. Likes sigurasg liked this post
  5. #103
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default

    Quote Originally Posted by thanvg View Post
    Ross has done a crazy modification on his FP2, adding a brake drum, operated by the rapid lever, only towards the other direction.
    That sounds like a nice way to do braking, though I'm unlikely to undertake that sort of project for the next decade or so . You'd also want to tie the brake into the motor off switch loop, that's what my Chinesium lathe does.

    Maybe I'm overthinking this though - perhaps I can just set the ramp-down time to whatever minimum works for slow spindle speeds. Presumably at slow spindle speeds the motor has much less inertia to contend with, and so should be able to brake quicker.
    At higher spindle speeds it'll then just end up braking a little bit, then coasting the rest of the way.

  6. #104
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default How to adjust X-gibs?

    Hey y'all,

    When I put the table back on my FP2, I adjusted the gibs pretty much higgledy-piggledy by feel. I went for where I can feel it noticeably tighten towards each end of travel. I did, at the time, wonder in which order to adjust them, but as I had other things to do before running the mill, I didn't dwell on it much.

    John's thread and his stuck gib(s) jogged my memory on this, and made me realize that I totally overlooked the gib locking screws.

    So, I'm going in again, hopefully to do this better. From this thread it sounds like I should adjust the upper gib first, then the lower one to pull the table back to the saddle.
    It looks like the locking screws should bear down on the shoulder of the gib adjusting screws to lock them in place after adjustment.

    Does this sound right?
    What sort of feel am I looking for when tightening the upper gib alone?

    Thanks,
    Siggi

  7. #105
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default

    Quote Originally Posted by ballen View Post
    I found Ross's thread, reposted a couple of years ago, with all the photos intact:
    https://www.practicalmachinist.com/v...e-brake-342223
    Wow, that's a very cool mod! Same config as my Chinesium mill to put the brake inside the machine-side pulley.

    Interestingly I got this pair of brake shoes with my mill
    img_20191108_182300.jpg
    which I initially thought belonged to the rapid feed clutch. A quick look at the parts diagram disabused me of that notion, so I guess they're just a random part that got pulled with the mill.
    Last edited by sigurasg; 11-08-2019 at 07:00 PM. Reason: them's shoes, with pads on, not just pads.

  8. #106
    Join Date
    Sep 2011
    Country
    GERMANY
    Posts
    2,655
    Post Thanks / Like
    Likes (Given)
    1644
    Likes (Received)
    936

    Default

    Hi Siggi,

    Quote Originally Posted by sigurasg View Post
    What sort of feel am I looking for when tightening the upper gib alone?
    For what it's worth, Franz told me to loosen both gibs. Tighten the first until the table won't move at the tightest point, and back it out half a turn. Then to do the same for the other gib. I don't recall the order.

    Cheers,
    Bruce

    PS: I do not recall if the slope on these gibs is 1:50 or 1:100. Suppose that it is 1:100. Then each 1mm of gib motion modifies the gap by 0.01mm. I also do not recall the thread of the gib screws, but suppose that it is 1mm per turn. Then half a turn of the gib screw moves the gib by 0.5mm, which in turn changes the gap by 0.005mm = 5 microns. So if my two assumptions are correct, then Franz's rule of thumb amounts to leaving about 5 microns = 0.0002" of free play.

  9. Likes sigurasg liked this post
  10. #107
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default

    Quote Originally Posted by ballen View Post
    For what it's worth, Franz told me to loosen both gibs. Tighten the first until the table won't move at the tightest point, and back it out half a turn. Then to do the same for the other gib.
    Thanks, this sounds nice and simple, I'll try see where I get with those instructions. I'm guessing the Y-gib would be adjusted the same way?

  11. #108
    Join Date
    Sep 2011
    Country
    GERMANY
    Posts
    2,655
    Post Thanks / Like
    Likes (Given)
    1644
    Likes (Received)
    936

    Default

    Quote Originally Posted by sigurasg View Post
    I'm guessing the Y-gib would be adjusted the same way?
    These were the generic instructions, meaning for all (X, Y, Z) gibs.

  12. #109
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default

    Quote Originally Posted by ballen View Post
    These were the generic instructions, meaning for all (X, Y, Z) gibs.
    Right - that's what I figured.
    I didn't quite man up for the X-gibs today, but I did measure the X/Y deflection, and I did adjust the Y-gib. Before adjustment, I managed nearly 10 thou deflection of the vertical head at max extension by pushing on the head by hand.
    I'd noticed there was a bit of a rattle in the test cutting I'd done to that point, and I'm guessing that's why - the gib was pretty loose.
    The tight spot in the Y-axis is way back on the movement, and I tightened the gib up until that spot felt uncomfortably hard to move, then relaxed it by a half turn. I didn't quite have the guts to go to where it bound up such that I couldn't move it at all, though maybe there isn't far to go from one to the other - I'd need more leverage on the hex key though, for sure.
    After this adjustment, I'm barely able to deflect the vertical head by a half thou or so by leaning into it at max extension. The only difference in feel is at the very back of the ram, where it feels noticeably tight.
    When I got the mill the large hex Y-lock at the front of the ram was pretty tight, so I wonder if the most recent user has been adjusting for wear by tightening the lock.

    The X-axis is clearly not optimal, as it gave me about a thou of deflection measured at one end, reaching out as far as I could with my test indicator and Noga base. I'll have to go in and play with it when I have some more time.

    I also trammed the head, and OMG the finish I get on a random 6061 aluminum drop with that random shell mill I got with the mill. It's like a mirror except for a little bit of cross-hatching. At 1000RPM and 5IPM it sounds like a lazy Sunday afternoon drive in the country side - I'm so going to enjoy this mill .
    Last edited by sigurasg; 11-10-2019 at 05:07 PM. Reason: Holy speling[sic] Batman!

  13. Likes ballen liked this post
  14. #110
    Join Date
    May 2018
    Country
    CANADA
    State/Province
    Quebec
    Posts
    71
    Post Thanks / Like
    Likes (Given)
    41
    Likes (Received)
    14

    Default

    Quote Originally Posted by ballen View Post
    These were the generic instructions, meaning for all (X, Y, Z) gibs.
    I just tightened up the X-gibs, drove them in as far as I dared at one end of travel where it's tightest, then backed off a half turn. Didn't overlook or forget the locking screws this time.
    The table feels nice and tight now, though it's noticeably freer in the center, as it to be expected given the age of the mill and the wear on the gibs when I had them out.

    Incidentally, is there a locking screw for the Y-axis gib? I looked for one but I couldn't find it.

  15. #111
    Join Date
    Oct 2017
    Country
    FINLAND
    Posts
    524
    Post Thanks / Like
    Likes (Given)
    85
    Likes (Received)
    156

    Default

    I believe the screw marked G is the locking screw

  16. Likes ballen, sigurasg liked this post

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •