Rack & pinion

[coolman]

I am considering using a Rack and Pinion instead of ballscrews. I have a few questions:

1) Where on the internet can I find Rack and Pinion parts?
2) What type of Rack and Pinion should I look for?
3) What is spring load and how can I build one? Any pictures?

I know things about ballscrews, but have little knowledge abou Rack and Pinions. Your help is appreciated.

Thanks,

[Al_The_Man]

Do a search of the forum here, it has been covered before.
Al

[jcc3inc]

Sir,

In answer to your questions.
1) You may purchase rack from Boston Gear and other gear type distributors.
We used to buy from Standard Steel Sepcialties, a manufacturer.

2) I would use 20 degree pressure angle rack and pinions as they run smoother than the more common 14 1/2 degree variety. The minimum number of teeth on the 20 degree pinion should be 18 teeth.

3) The separating force for 20 degree components is .364 x the drive force applied. Thus if you need 100# drive force, the spring engagement force must be greater than 36.4# in order to keep the pinion engaged.

4) In order to keep the engagement force constnt for changing directions of force, you must have the pivot line (the hinge centerline) intersect the pitch line of the gear rack. Otherwise, if the pivot is above or below the pitchline of the rack, the pinion will be pulled into engagement when driving the load in one direction, and pulled out of engagement when the direction is reversed.

I put some pictures on my test setup on a near inquiry of this group.

Regards,
Jack C.

[kevlar129]

IMHO, Martin Gear is another great source.
Happy machining...
C

[cadman]

Good info here:


www.atlantadrives.com

[dgalaxy]

does boston gear make a steel pinion for 24dp 20 degree it looks like there all delrin and brass is this ok

by the way what 14.5 degree gear set is every one buying from mcmaster carr
for like plasmas

[Al_The_Man]

Boston Gear have steel and cast iron in 24dp 20° angle YA series.
Here is the previous post on the Rosta tensioner I used http://cnczone.com/forums/showthread...ighlight=rosta
Al.