ISEN-ASTC-L is a service of the Association of Science-Technology Centers Incorporated, a worldwide network of science museums and related institutions. ***************************************************************************** Jeff-- Can you seperate the user from the lens with one more layer of mechanicals? For example, can you use a little chain drive system with a crank? Or selsyn motors? If one of your axes is vertical, you'd need to be concerned with old Father Gravity, too. How about a magnetic cushion? Attach magnets of one pole to your lens armature, and magnets of another pole on your frame. If the magnets are reliable and strong, an over-exhuberant user could shove the lens at top speed, but as long as it's prevented from reaching another rigid body (in this case by magnetic field) for impact, it's all good, right? Just brainstorming. I have sketch book pages full of doodles of two axes sliders--for some reason I daydream about these things every so often-- but I have never built one. --Jason __ JasonJayStevens JasonJayStevensStudio [log in to unmask] www.potterbelmar.org/jjss 536 Roosevelt Avenue San Antonio, Texas 78210 210.818.0642 On Dec 22, 2008, at 10:06 AM, Jeff Courtman wrote: > ISEN-ASTC-L is a service of the Association of Science-Technology > Centers > Incorporated, a worldwide network of science museums and related > institutions. > ********************************************************************** > ******* > > I need to build a 2 axis slider to move a magnifying lens around a > large graphic (think of 'where's waldo'). I plan on using linear > bearings and wanted to know from those of you with experience what > might be the best way to control the friction in the movement (so > an over-exuberant 7 year old, like my son) can't wind up and sling > it from one side to the other..... > > Thanks in advance, > > Jeff > > > > > > ********************************************************************** > * > For information about the Association of Science-Technology Centers > and the Informal Science Education Network please visit www.astc.org. > > Check out the latest case studies and reviews on ExhibitFiles at > www.exhibitfiles.org. > > The ISEN-ASTC-L email list is powered by LISTSERVR software from L- > Soft. To learn more, visit > http://www.lsoft.com/LISTSERV-powered.html. > > To remove your e-mail address from the ISEN-ASTC-L list, send the > message SIGNOFF ISEN-ASTC-L in the BODY of a message to > [log in to unmask] *********************************************************************** For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org. Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org. The ISEN-ASTC-L email list is powered by LISTSERVR software from L-Soft. To learn more, visit http://www.lsoft.com/LISTSERV-powered.html. To remove your e-mail address from the ISEN-ASTC-L list, send the message SIGNOFF ISEN-ASTC-L in the BODY of a message to [log in to unmask]