2 1/2" - 4 Single Lead Acme
2 1/2" - 4 Single Lead Acme
This 2 1/2”-4 single lead acme machine screw is available in both alloy steel and stainless steel with a corresponding aluminum bronze nut. This is available with right-hand or left-hand threads.
| Machine screw specifications | RH | LH |
|---|---|---|
| Alloy steel screw part no. | AS 250 R 025 A | AS 250 L 025 A |
| Stainless steel screw part no. | AS 250 R 025 S | As 250 L 025 S |
| Thread form | Acme | |
| Screw diameter - turns/inch | 2 1/2" - 4 | |
| Pitch/Lead | 0.250 in. | |
| Root diameter | 2.193 in. | |
| Screw weight (lb./ft.) | 13.4 | |
| Torque to raise 1 pound | 0.294 in.-lb. | |
| Maximum screw length | 20 feet* | |
*12 feet for stainless steel stock
Nut and Flange Specifications
| Nut specifications | RH | LH |
|---|---|---|
| Nut part number | AN 250 R 025 B | AN 250 L 025 B |
| Nut with flange | AF 250 R 025 | AF 250 L 025 |
| Dynamic load capacity (lbs.) | 40,000 | |
| Static load capacity (lbs.) | 100,000 | |
| Efficiency | 21.2% | |
| Material | Bronze | |
| Nominal Diameter "A" | 3.38 in. | |
| Nut length "B" | 3.38 in. | |
| Thread length "C" | 1.560 in. | |
| Thread size | 3.137-12 UN | |
| Flange part number | FL-3137 | |
| Flange diameter "D" | 5.38 in | |
| Flange thickness "E" | 1.580 in. | |
| Flange hole diameter "F" | 0.656 in. | |
| Number of holes in flange "G" | 6 | |
| Flange Bolt Circle "H" | 4.375 in. | |
| Flange material | black oxide coated steel | |
2D/3D Drawings
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Product Media
- Alloy steel or stainless screw
- Aluminum bronze nut
- Steel flange with black oxide coating
Sample Part Number:
Click on the part number to reveal additional information about the screw design and shaft codes.
Model Number
Thread Form
A: Acme
S: Stub Acme
Component
A: Assembly
S: Screw - without ball nut or bearing mounts
Screw Diameter - Thread direction - TPI (English)
| Dia/TPI | Code |
|---|---|
| 1/2 – 8 | 050 R 013 (Stub Acme) |
| 5/8 – 8 * | 063 R 013 (Stub Acme) |
| 5/8 – 4 * | 063 R 025 (Stub Acme) |
| 5/8 – 2 | 063 R 050 (Stub Acme) |
| 3/4 – 5 * | 075 R 013 |
| 7/8 – 2 * | 088 R 050 |
| 1 –10 | 100 R 010 |
| 1 – 4 * | 100 R 025 |
| 1 – 2 | 100 R 050 |
| 1 – 1 | 100 R 100 (Stub Acme) |
| 1 1/4 – 4 | 125 R 025 |
| 1 1/2 – 4 | 150 R 025 |
| 1 1/2 – 2 2/3 | 150 R 038 |
| 1 1/2 – 2 2/3 * | 150 R 038 (Stub Acme) |
| 1 1/2 – 2 | 150 R 050 |
| 2 – 4 | 200 R 025 |
| 2 – 2 * | 200 R 050 |
| 2 1/4 – 4 * | 225 R 025 |
| 2 1/4 – 2 * | 225 R 050 |
| 2 1/2 – 4 | 250 R 025 |
| 2 1/2 – 2 * | 250 R 050 |
| 3 3/8 – 1 1/2 | 338 R 067 (Stub Acme) |
| 3 1/2 – 1 1/2 | 350 R 067 |
| 3 3/4 – 1 1/2 | 375 R 067 |
| 4 1/2 – 1 1/2 | 450 R 067 |
| 5 – 1 1/2 | 500 R 067 |
| 6 – 1 1/3 | 600 R 075 |
R – Right-hand – all thread diameters/leads are available with right hand threads
L – Left-hand *- Substitute an ”L” in the part number for left hand leads
Stub Acme screws offer a larger root diameter than their Acme counterparts
*Available in stainless steel
Screw Material
A: Alloy Steel
S: Stainless Steel
Note: not all threads or materials are available for all sizes
First End of Screw
(Flange or threaded end of nut always faces second end)
| Bearing Mount Options | Machining Options (choose one that corresponds to the bearing block) |
|---|---|
| SB - Simple Single* | 1N – Threaded shaft only |
| DB - Simple Double | 2K – Thd Shaft w Kwy, 2L – Thd Shaft no Kwy, 2N – Threaded shaft only |
| FB - Fixed Double | 3K – Thd Shaft w Kwy, 3L – Thd Shaft no Kwy, 3N – Threaded shaft only |
| XX - No Bearing | 4K – Shaft w Keyway, 4L – Shaft no Keyway, 4N – Support only, XX – No Machining |
(When selecting ”XX – No Bearing”, choose from mounting options 1K through 4N or XX, above)
* All Simple Single bearing mounts are designed for radial loads only
Second End of Screw
(Flange or threaded end of nut always faces away from second end)
| Bearing Mount Options | Machining Options (choose one that corresponds to the bearing block) |
|---|---|
| SB - Simple Single* | 1N – Threaded shaft only |
| DB - Simple Double | 2K – Thd Shaft w Kwy, 2L – Thd Shaft no Kwy, 2N – Threaded shaft only |
| FB - Fixed Double | 3K – Thd Shaft w Kwy, 3L – Thd Shaft no Kwy, 3N – Threaded shaft only |
| XX - No Bearing | 4K – Shaft w Keyway, 4L – Shaft no Keyway, 4N – Support only, XX – No Machining |
(When selecting ”XX – No Bearing”, choose from mounting options 1K through 4N or XX, above)
* All Simple Single bearing mounts are designed for radial loads only
Nut Properties
B - Bronze
X - Do Not Include Nut in Assembly
Other Options
F - Include Flange
X - Do Not Include a Flange
Screw Length 000.00"
Enter value in inches with decimal if needed
Note that available screw length varies among screw sizes.
DB Bearing Blocks
| Screw Number | Bearing Mount No. | A | B | C | D | E | F | G | H | I | J | K | L |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AS250R025A | DB-45 | 8.500 | 5.625 | 2.813 | 1.000 | 3.625 | 3.313 | 6.625 | 0.873 | 3.468 | .813 (6x) | 1.013 Thru | 1.720 |
| AS250R050A | 1.563 C'Bore | ||||||||||||
| 3.500 Deep |
SB Screw End Conditions
| Screw Number | Bearing Mount No. | o S1 | A1 | A2 | A3 | A4 | A5 | A6 | o A7 | A8 | A9 | A10 | A11 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AS250R025A | NA | 1.7721 | 1.550 | .960 | .80 | .315 | .984 | 2.000 | 3.50 | 1.767-18 UNS | W-09 | N-09 | 6309 |
| AS250R050A | 1.7716 | .313 |
DB Screw End Conditions
| Screw Number | Bearing Mount No. | oS1 | oS2 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 | A9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AS250R025A | DB-45 | 1.7721 | 1.375 | 6.68 | 4.49 | 3.875 | .984 | .063 | 1.767-18 UNS | W-09 | N-09 | 5/16 x 1/12 |
| AS250R050A | 1.7716 | 1.374 |
FB Screw End Conditions
| Screw Number | Bearing Mount No. | oS1 | oS2 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 | A9 | A10 | A11 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AS250R025A | NA | 1.7721 | 1.375 | 8.62 | 6.37 | 5.60 | 4.694 | .984 | 2.75 | .035 | 1.767-18 UNS | W-09 | N-09 | 5/16 x 1 1/2 |
| AS250R050A | 1.7716 | 1.374 |