Shop Floor Talk  

Go Back   Shop Floor Talk > Welding and Metalworking Forums > Fabrication

SFT Search:   
Reply
 
Thread Tools Display Modes
  #1  
Old 08-15-2022, 03:37 PM
Jades1 Jades1 is offline
Junior Member
 
Join Date: Feb 2022
Location: San Diego
Posts: 13
Default DIY Standing Desk with Linear Rails

Hi all,

I'm trying to make a desk that will move up and down on linear rails. There will be two stop collars to stop the cartridges holding the monitor as well as a pulley system. Then there will be a desk below, that will be on another set of cartridges. The issue I'm experiencing is a lot of racking, such that it is very hard to move the cartridges in concert because they quickly become no longer parallel. Is there a fix that you can think of? Would two pieces of steel in x shape going to each cartridge solve the issue?

Thanks,

James
Attached Thumbnails
Click image for larger version

Name:	IMG_1062.jpg
Views:	85
Size:	173.2 KB
ID:	165464  
Reply With Quote
  #2  
Old 08-15-2022, 04:02 PM
toprecycler's Avatar
toprecycler toprecycler is offline
Administrator
 
Join Date: Jan 2009
Location: Petoskey, Michigan
Posts: 6,270
Default

An x brace will help the racking a lot. Are the main rails fastened to the wall? If so, are they parallel?

You might still have problems, unless you rig up some sort of cable and pulleys so both sides will raise together.


Sent from my iPhone using Tapatalk
__________________
Brian

You don't know what you don't know.

"It's what you learn after you know it all that counts." John Wooden
Reply With Quote
  #3  
Old 08-15-2022, 04:55 PM
Jades1 Jades1 is offline
Junior Member
 
Join Date: Feb 2022
Location: San Diego
Posts: 13
Default

Thanks...yes they are fastened to the inside of the window frame, butting up against a ridge (so they should both be parallel).

I do have a double pulley and then a pulley on the table, such that they should both be lifting at the same time. Isn't there any way to get it perfect? I'm not great with pulleys and couldn't find a lot of information out there for this purpose.

Best,

James
Reply With Quote
  #4  
Old 08-15-2022, 08:12 PM
digger doug's Avatar
digger doug digger doug is offline
Banned
 
Join Date: Jan 2008
Location: NW Pa
Posts: 14,033
Default

Look at a garage door torsion spring set-up.
Qty (2) winding drums, one on each side of door, connected by a shaft to keep them timed.
Reply With Quote
  #5  
Old 08-15-2022, 09:17 PM
arizonian's Avatar
arizonian arizonian is offline
Elite Member
 
Join Date: Jul 2007
Location: Tucson, Arizona
Posts: 1,932
Default

You need two cables and four pulleys. The cables form an X as it crosses the center of the mechanism. Think old school drafting table.

This guy has some thoughts on a problem with a range of motion similar to yours, but way more complicated. About the four minute mark is where his problems and solutions start to appear.
__________________
Bill in sunny Tucson

I believe in gun control.

Gun Control: The ability to consistently hit what you are aiming at.

Weldor by choice, engineer by necessity.
Reply With Quote
  #6  
Old 08-15-2022, 10:13 PM
Shade Tree Welder's Avatar
Shade Tree Welder Shade Tree Welder is offline
Grumpy Bastard
 
Join Date: Jun 2004
Location: Kankakee County, IL
Posts: 22,408
Default

Quote:
Originally Posted by digger doug View Post
Look at a garage door torsion spring set-up.
Qty (2) winding drums, one on each side of door, connected by a shaft to keep them timed.
Oh no that is not complex enough, he should run balanced
hydraulic cylinders, at a minimum of 3000 psi.
__________________
Shade

"Prepare to defend yourselves."
-- Sergeant Major Basil L. Plumley, Ia Drang Valley
Reply With Quote
  #7  
Old 08-15-2022, 10:17 PM
Shade Tree Welder's Avatar
Shade Tree Welder Shade Tree Welder is offline
Grumpy Bastard
 
Join Date: Jun 2004
Location: Kankakee County, IL
Posts: 22,408
Default

Quote:
Originally Posted by arizonian View Post
You need two cables and four pulleys. The cables form an X as it crosses the center of the mechanism. Think old school drafting table.
That but I think you need longer linear bearings. You are calling them
cartridges, they are the linear bearings or double the number of them and
mount them on a board or frame that is co-planar with your guide rails, If you
go with the doubling of them have them mounted at least 6" apart on center.
__________________
Shade

"Prepare to defend yourselves."
-- Sergeant Major Basil L. Plumley, Ia Drang Valley
Reply With Quote
  #8  
Old 08-16-2022, 06:33 AM
digger doug's Avatar
digger doug digger doug is offline
Banned
 
Join Date: Jan 2008
Location: NW Pa
Posts: 14,033
Default

Quote:
Originally Posted by Shade Tree Welder View Post
Oh no that is not complex enough, he should run balanced
hydraulic cylinders, at a minimum of 3000 psi.
You forgot to put a computor on it sir.....
Reply With Quote
  #9  
Old 08-16-2022, 06:34 AM
digger doug's Avatar
digger doug digger doug is offline
Banned
 
Join Date: Jan 2008
Location: NW Pa
Posts: 14,033
Default

Quote:
Originally Posted by arizonian View Post
You need two cables and four pulleys. The cables form an X as it crosses the center of the mechanism. Think old school drafting table.

This guy has some thoughts on a problem with a range of motion similar to yours, but way more complicated. About the four minute mark is where his problems and solutions start to appear.
I forgot all about that system.
It would be the easiest.
Reply With Quote
  #10  
Old 08-16-2022, 09:11 AM
Lew Hartswick Lew Hartswick is offline
Elite Member
 
Join Date: May 2008
Location: Albuquerque NM
Posts: 4,671
Default

:-) 2 lead screws geared together. :-)
...lew...
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Web Search:

All times are GMT -5. The time now is 01:38 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.