HELAC ALTERNATIVE
HTX70-MS-RF-360-SS-O-H Rotary Actuator
Alternative rotary actuator for the Helac HTX70-MS-RF-360-SS-O-H, a splined-shaft 360-degree helical actuator listed by Atlas under part number 3128307978, supplied for aftermarket replacement.
Atlas part number
3128307978
Alternative rotary actuator for Helac HTX70-MS-RF-360-SS-O-H.
Specifying a new program? Talk to our engineering team →
Independently supplied alternative — not an original Helac or Atlas part. Compatibility is verified before ordering.
Code anatomy
What each part of this code means
Every segment below is read from the manufacturer’s published ordering key. Where a segment is not published, we say so instead of guessing — those are the ones to confirm from the tag or the drawing before ordering.
HTX70-MS-RF-360-SS-O-H
HTX series
| Segment | Field | What it tells you |
|---|---|---|
| HTX70 | Series and size | HTX series, size 70 — the HTX family uses its own key |
| MS | Measurement system | Custom design — metric threads on a special OEM build |
| RF | Housing / mounting | Rear flange |
| 360 | Rotation | Standard 360° rotation |
| SS | Shaft / flanges | Shaft code not in the published ordering key — confirm against the tag or drawing |
| O | Valve | No valve |
| H | Seals and bearings | Standard seals and bearings |
The HP/HTX families write the size into the series field; the remaining positions follow the same order as the L-series key.
Full ordering key and how to read a tag: identifying a rotary actuator.
What the 360° sweep changes on this build
A full-turn build: the output sweeps a complete revolution. The hose loop and its clamping have to survive the whole sweep, which is why a full-turn unit is checked as a hose-routing question as well as a torque question.
- Check the hose loop clears the housing through the full revolution, not just at the rest position.
- Confirm the duty actually needs a complete turn — a half-turn build of the same size is the usual choice where it does not.
- Rotation stops, if the machine has them, sit outside the actuator and still have to be checked.
When this sweep is the right build
- Duties that genuinely index through a full revolution — rod handling, turret positioning, continuous swing.
- Linkages where the return path is part of the cycle rather than a reversal of the same half turn.
- Machines already built around a full-turn hose loop, where a half-turn unit would leave the routing over-travelled.
Confirming the sweep on the machine
- Turn the linkage through a full revolution by hand and watch the hose loop — a unit that binds at three quarters of a turn is a routing problem, not a torque problem.
- Check whether the machine has an external rotation stop; if it does, the sweep on the tag is not the limit the linkage actually uses.
How the sweep sits in the order code
The sweep is the fifth segment of the code. Going to the half-turn build of the same size changes that segment and the internal stop tube; flange, shaft and valve stay as they are. Where a machine only needs two positions, the half-turn build is the shorter hose route and the smaller envelope.
Where these two builds get mixed up
- A full-turn unit is sometimes quoted where the linkage only swings half a turn, which over-travels the hose loop for no benefit.
- If a full-turn unit will not pass a quarter or half turn under load, the cause is usually hose routing or an external stop, not the actuator.
At a glance
Quick reference
- Original model
- HTX70-MS-RF-360-SS-O-H
- Original brand
- Helac
- Type
- Rotary actuator
- Rotation
- 360°
- Original part no.
- 3128307978
Equipment reference
Known applications
This actuator is associated with the following Atlas Boomer and Simba rigs. Confirmation against your machine build plate is recommended.
If your machine is not listed, send the full model and serial number — other builds may use the same actuator.
Confirmed data only
Technical specifications
| Product type | Hydraulic rotary actuator |
|---|---|
| Rotation angle | 360° |
| Further data | Torque, pressure, port and mounting dimensions are shared with the engineering drawing on request. |
HM alternative model — confirmed on inquiry. Send us your original model number, part number or machine details and we confirm the matching configuration, specifications and compatibility, then quote. The exact ordering code — rotation, output and valve arrangement — is confirmed against your unit and is not published online.
Questions
Frequently asked questions
What does the HTX70-MS-RF-360-SS-O-H replace?+
It is the model code for a Helac helical rotary actuator providing 360° rotation. It is listed by Atlas under part number 3128307978. Our alternative is matched to the same rotation and mounting interface.
How do I know this fits my machine?+
The same actuator is recorded on the Boomer 104, Boomer K41, Boomer K41x, Simba H157. Before quoting we confirm the mounting face, port position and rotation against the tag and a photo of your unit, so the replacement matches your exact build.
Which rigs use Atlas part number 3128307978?+
The splined-shaft 360-degree actuator under Atlas Copco / Epiroc part number 3128307978 is recorded on the Boomer 104, Boomer K41, Boomer K41x and Simba H157 rigs, corresponding to the Helac HTX70-MS-RF-360-SS-O-H configuration. Send the part number on your tag or a nameplate photo and we confirm mounting, shaft and ports before quoting.
Why is the exact HM model and price not shown?+
We confirm the HM model per inquiry after verifying the interface and operating parameters with you. This avoids shipping a part that looks right by model name but differs in mounting or rotation. Price is provided with that confirmed quote.
Request a check
Looking for an alternative to this model?
Send us the original model number, part number, machine model or a drawing. We check the available option and confirm specifications and compatibility for you.
- Original model / part number
- Machine brand & model
- Quantity & annual demand
- Mounting photo or drawing (if available)
Or email directly: hm@hmhydraulics.com