RUPES Backing Plate Screws

RUPES Backing Plate Screws for the LK900E

RUPES backing plate screws (part 9.614) are the black oxide, Phillips-head screws that hold the backing plate on the RUPES LK900E Mille polisher. Six of them pass through the plate into the machine's aluminium support, each one with a 9.393 backing plate washer seated on the plate and a 9.1808 contact washer beneath the screw head. RUPES uses the same 9.614 on the LH19E rotary to hold its lower spindle flange, while the LH19E's backing plate threads straight onto the spindle with no screws at all. The LK900E's gears force the plate to turn, so a stripped, loose, or missing screw tends to show up as a plate that won't sit square.

Match the screw to the machine. RUPES's LHR21ES, LHR15ES, and Mark III BigFoot polishers and the Skorpio III sander hold their plates with a different part, the 9.715 socket cap screw with active washer, and RUPES specifies each screw for its own tools. Swap out any 9.614 with a rounded-out Phillips recess when the plate comes off, and look over the six-hole gasket (68.379) under the plate at the same time. Shops that run the LK900E every day keep spares in the drawer with the rest of the plate hardware.

What Makes it Great:

🔩 Six-Point Plate Mount: Six screws share the gear-driven load around the plate, so it stays square on the aluminium support instead of rocking on one loose fastener.

🛡️ Black Oxide Finish: The dark oxide coating adds mild corrosion resistance for a fastener that sits right under a wet, compound-loaded pad.

🪛 Phillips Drive: A standard Phillips screwdriver takes them out and puts them back, so a 5" to 6" plate swap needs no special tool.

🔁 Shared With the LH19E: The same part number covers the LH19E's spindle flange screw, so one set of spares serves a shop running both RUPES machines.

Frequently Asked Questions

How many screws hold the LK900E backing plate?

Six. Each one goes through the plate with two washers: the 9.393 on the plate side and the 9.1808 contact washer next to the screw head. RUPES says not to tighten them until the plate is seated on its gasket with all six holes lined up.

Which RUPES backing plate screw do I need?

It depends on the polisher. The LK900E takes six of these 9.614 screws. The LHR21ES, LHR15ES, LHR21 and LHR15 Mark III, and the Skorpio III sander take the 9.715 socket cap screw with active washer. The LH19E's plate threads on, so it uses no plate screw.

Can I use a hardware store screw on the LK900E backing plate?

RUPES's LK900E manual says only original RUPES parts should be fitted, and that fitting non-original parts terminates the warranty. The 9.614 is the screw RUPES lists for the plate.

Specifications:

Installation (Best Practices):