|Harry Crowther||17/04/2019 15:43:55|
|4 forum posts|
I was wondering if anyone knows the difference between a 'trapezoidal lead screw' and a 'ACME lead screw'? Or is ACME the brand name?
|Brian G||17/04/2019 16:18:44|
|461 forum posts|
They are both trapezoidal Harry. Generally I think the difference is whether the machine is imperial or metric. Acme (named for the Acme Machine Company) has a thread angle of 29 degrees and dimensioned in inches, whilst ISO trapezoidal threads have a thread angle of 30 degrees and are dimensioned in mm. I suspect however that in the long tradition of mixing standards you can get metric machines using the Acme thread form or imperial machines using the ISO form.
|Zane Crowther||18/04/2019 09:28:58|
|4 forum posts|
There isn't much difference as mentioned above, its just that the American ACME form has an angle of 29 degrees, while the metric trapezoidal is 30 degrees. So trapezoidal lead screws are more common in the UK.
15160 forum posts
You will also find that ACME is made in imperial pitches given as tpi or threads per inch whereas the Trapezoidal come sin metric pitches eg 2mm , 3mm etc.
I would not say TR screws are more common in the UK as there are still a lot of old machines running imperial ACME screws but anything new and metric will have TR
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.