Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 16
-
1st March 2016, 04:13 PM #1
I need help with my FK12 bearing block
Hi All,
My TM20VL mill conversion uses FK12 bearing blocks to retain the RM1605 ballscrews. I measured the backlash in the X axis and it is around 0.12mm.
I'm sure it should only be about 0.02-0.03mm
The sources of backlash as I see it are,
- ballnut
- FK12 bearing block
- belt drive.
I seem to remember a discussion on the FK12 block and there need to put shims in them. (Rod?) can anyone help me out on how to check or fix the FK12 blocks?
Cheers,
Peter.Homann Designs - http://www.homanndesigns.com
-
1st March 2016 04:13 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
1st March 2016, 06:57 PM #2SENIOR MEMBER
- Join Date
- Feb 2008
- Location
- Australia
- Posts
- 988
I purchased some a few months back (two sets of FK12 Bearing Blocks), they had standard bearings instead of angular contact bearings in them, and the spacers were just complete junk, that's not to say you got the same junk but just open them up and take a look, bearings should slide right out.
BTW it's about time you got stuck into that mill and finished it
-
1st March 2016, 11:13 PM #3GOLD MEMBER
- Join Date
- May 2003
- Location
- Perth WA
- Posts
- 3,784
Peter,
I found they needed shims between the inner race of the bearings. I used brass shims and made them with an hollow punch.Cheers,
Rod
-
1st March 2016, 11:34 PM #4SENIOR MEMBER
- Join Date
- Sep 2009
- Location
- Newcastle
- Posts
- 549
My blocks benefited from shimming. I used a soft drink can cut with scissors. A bit tricky to do but it helped significantly.
-
2nd March 2016, 10:42 AM #5
Thanks for all the replies.
I'll pull it apart on the weekend.
Cheers,
PeterHomann Designs - http://www.homanndesigns.com
-
7th March 2016, 08:52 AM #6
If there is a large amount of backlash in your nut then you can take the backlash out of the nut if you have room by putting a second nut under tension
Russellvapourforge.com
-
7th March 2016, 12:38 PM #7
Hi Russel,
Thanks, one of my options is to get some double ball nuts from linearmotionbearings2008.
Hopefully I can use the nut on my existing screws.
Paul suggested that I check that I've installed the AC bearings in the correct direction as well. I think I did but I need to check it.
Cheers,
PeterHomann Designs - http://www.homanndesigns.com
-
7th March 2016, 04:24 PM #8
Do the double ball nuts remove all the backlash?
I used 2 nuts tensioned apart to takeup the backlash has work very well for many years.
Rvapourforge.com
-
7th March 2016, 06:21 PM #9
I believe that they do. I'm not up on how it is done though.
3 Double Ball Nuts Double Ballnuts Ball SCREWS1605 2005 C7 for CNC Router | eBay
I could do it the way you suggest. That way it wouldn't reduce the travel.
The ballscrew mount is threaded so I could possibly;
- use a longer bolt to extend through the block
- use a threaded rod with nylock nuts on either side
- use shorter bolts screwed in from each end. (the mount block may not be wide enough)
What do you use to tension the 2nd nut?
Cheers,
Peter
X-ScrewInstalled.jpgX-ScrewInstalled2.jpgHomann Designs - http://www.homanndesigns.com
-
8th March 2016, 01:01 PM #10
I used some heavy duty Belleville washer, there under the 2 nuts on the left (2 washer on each side) in the photo attached
The gap between the left ballnut and mount is there to allow for the small varation in the ball screw. This movement stops the ballnuts jamming up but take out all of the backlash.
Hope you can follow how this works......
Rvapourforge.com
-
8th March 2016, 01:04 PM #11
Found this photo of a different way of mounting second ballnut
vapourforge.com
-
8th March 2016, 02:40 PM #12
Hi Russel,
Thanks for that. It explains it perfectly.
Cheers,
PeterHomann Designs - http://www.homanndesigns.com
-
8th March 2016, 03:52 PM #13SENIOR MEMBER
- Join Date
- Sep 2009
- Location
- Newcastle
- Posts
- 549
If you use a fixed spacer I think you need to ensure rotational alignment stays fixed. I'm not sure if using springs removes this need - probably.
-
18th March 2016, 11:24 AM #14Member
- Join Date
- Jul 2009
- Location
- Detroit, Michigan
- Age
- 60
- Posts
- 72
Just an FYI.
My friends in the UK, no longer purchase from linearmotionbearings (Chai).
They now purchase from BST Automation on Aliexpress, and find the prices as good or better, and the components to be far superior.Gerry
-
18th March 2016, 11:36 AM #15
Hi Gerry,
Thanks for that. I've looked at BST but haven't had a chance to purchase yet.
Cheers,
PeterHomann Designs - http://www.homanndesigns.com
Similar Threads
-
Too much bearing grease?
By nadroj in forum METALWORK FORUMReplies: 16Last Post: 16th February 2015, 07:16 PM -
Bearing
By WesP in forum METALWORK FORUMReplies: 4Last Post: 25th October 2014, 12:16 PM -
A Compendium of Block Planes: The HNT Gordon Block Plane
By derekcohen in forum HAND TOOLS - UNPOWEREDReplies: 8Last Post: 16th August 2008, 09:54 PM -
Bearing run-out
By John Saxton in forum ROUTING FORUMReplies: 10Last Post: 8th January 2001, 01:04 AM