Rotational to linear movement 2

[blckwtr]

Which is the best screw thread to transfer torque into a linear motion? Trapezoidal, Acme or something like that? It will be used several times, so friction must be small such that the thread lasts for some time. The bolt is approximately 30mm diameter.

 

[patprimmer]

Big hint

Have you looked at the lead screw on a lathe or the threads on the screw in a vice.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[benta]

For minimum friction, use a ball screw.

Benta.

 

[handleman]

Here's a similar question:

What's the best motorized vehicle? Miata, bulldozer or something like that? I need it to have an engine and be able to drive both forward and backward.

In all seriousness, we will need a bit more detail to give a meaningful answer.

-handleman, CSWP (The new, easy test)

 

[blckwtr]

No worries, in my kind of work I am used to give a general answer in an early design phase based on the information we got, usually very limited. The best engineers I know can do this provided they know what they talk about, and add more information like; The best screw thread for this purpose is *****, but be aware of ****, and do not forget *****. One can't be an expert on everything handleman...

 

[handleman]

So you expect someone to write you a free dissertation on screw thread selection? Frankly it's a bit lazy of you. Based on your information, nobody can say "The best screw thread for this purpose is ******" because you have given no detail about the purpose. How about things like:

Speed (rotational/linear)
Available torque input
Required force output
Load
Vertical/horizontal
Required positional accuracy.
What does "Several" mean? 15 times in lifetime, or 3x/sec?
What are the operating conditions? Heat, contamination, liquids, cleanliness requirements?
Required lifetime?




-handleman, CSWP (The new, easy test)

 

[rb1957]

always use acme ... ask coyote ! ...

 

[ornerynorsk]

For low tech (read as low cost), you cannot beat acme. If you still have a budget after these last 9 months, go with ball screw.

 

[blckwtr]

Thank's... I will go for Acme or Stub Acme, we use it all the time in our applications, so it's familiar to us.

Have a nice day...

 

[ornerynorsk]

A scotch yoke also does a neat job of rotary to linear, depending on your operating parametrs and loads.

 

[Wrenchbender]

I stand with Patprimer, Rb1957 and Ornery on the Acme side of the fence. Also check this thread (no pun) from several weeks ago.

http://www.eng-tips.com/viewthread.cfm?qid=244864&page=2

 

[FeX32]

What about a simple slider crank mechanism or a rack/pinion combination.


Fe

 

[blckwtr]

Maybe for another application, I must have a rotational nut for this oil tool (expandable plug). Preferrably everything should be as "round" as possible...