| BALLSCREW/LEADSCREW
ACCURACY CHART
W/O PART NUMBERS
(See important notes at bottom of this
chart) |
BALLSCREW PRECISION
5/8" DIA., 5TPI (0.200" LEAD) |
ACME LEADSCREW PRECISION
5/8" DIA., 8 TPI (0.125" LEAD) |
| MANUFACTURERS
(in
alphabetical order) |
"HIGH PRECISION"
Usually 0.0005 in./ft. |
"PRECISION"
Usually 0.001 in./ft. |
"STANDARD"
Usually 0.004 in./ft. |
"HIGH PRECISION"
Usually 0.0005 in./ft. |
"PRECISION"
Usually 0.001 in./ft. |
"STANDARD"
Usually 0.004 in./ft. |
| Kerk Motion
http://www.kerkmotion.com
|
N/A |
N/A |
N/A |
N/A |
Lead accuracies are available up to .0001 in./in. (mm/mm).
|
N/A |
| Nook
Industries
http://www.nookindustries.com
|
?0.0005 in./ft.
"Precision Ground (SGT)" |
?0.001 in./ft.
"Precision Rolled (XPR)"
|
?0.004 in./ft.
"Standard Rolled (SRT)" |
Ground +/- 0.0005"/ft.
"GROUND ACME SCREWS
Ground thread screws offer higher lead accuracy performance for
applications where positioning tolerances are extremely critical." |
Milled +/- 0.002"/ft.
"MILLED ACME SCREWS
Milled thread screws allow more variety in journal machining,
particularly where a design requires the journal O.D. to be larger than
the screw major diameter." |
Rolled +/- 0.0003"/"
"ROLLED ACME SCREWS
Nook rolled thread acme screws offer the highest precision and largest
selection of size and pitch in the industry. Rolled thread screws are cost
effective and are stocked for quick delivery." |
| Rockford
Ballscrew
http://www.rockfordballscrew.com
|
+/- .003" per foot
"R32"
"Premium grade screw
will not exceed..." |
"R31" |
+/- .007" per foot
"R30"
"Standard screw will not exceed..." |
N/A |
N/A |
0.010in./ft. |
Roton
http://www.roton.com
|
N/A |
N/A |
0.010 in./ft. |
N/A |
N/A |
ACME 0.009 in./ft. with tolerance of .006" and .003"
depending on size of screw.
For 5/8" dia. most likely .003"
which brings lead accuracy to between .015" to .003" |
| Thomson/Danaher
http://www.danahermotion.com
|
0.0005 in./ft. available
"Precision Plus" |
N/A |
*Guessing 0.004 in./ft.
"Precision" |
0.003 in./ft.
"Precision grade SPR" |
N/A |
0.010 in./ft.
"Standard grade SRA" |
IMPORTANT NOTES!
- Manufacturers listed sell inch screws.
Companies that only sell metric screws are not listed (sorry!).
- All information gathered from mfg's
websites and literature. Most information is NOT clearly available even
when contacting their sales reps.
- All text in quotes "" are stated
marketing from the respective mfg's literature.
- Accuracry depends on "grades" and
diameters. Data in this chart is for 5/8" dia. sizes in ballscrews and
acme leadscrews.
- Note that some mfg's use in/in while
other use in/ft to state their lead accuracies. To convert between in/in
and in/ft you will need to multiply/divide by a factor of 12. Thus, for
a stated lead accuracy of 0.0003 in./in. (sounds pretty good right?) it
is in fact 0.0003 in./in. * 12 in./1 ft. = 0.0036 in./ft. or roughly
0.003 in./ft. This is considered "standard" accuracy as far as
ballscrews are concerned.
- 5/8" diameter is a cost-effective
size.
- For ballscrews, smallest lead is
0.200" (5 TPI) while ACME leadscrews can get down to .100" (10 TPI)
- On the Asian machines converted to CNC,
a good match would be the "precision" class of screws. If cost is a
major factor of your conversion, the "standard" class of screws is not
only easier to purchase, they are also much more affordable.
Copyright 2011. figNoggle
Designs. All rights reserved. |
