Alpha® PVA-5/8 Snail-Lock Adapter — 4" Backer for PVA QC Discs (5/8"-11)
The Alpha® PVA-5/8 is the 4" aluminum snail-lock backer/adapter required to run Alpha PVA QC "Quick Change" dry-polishing discs. It threads directly onto any low-speed polisher or variable-speed grinder with a 5/8"-11 spindle, and its built-in SFAT snail-lock holds PVA QC discs securely so grit changes take seconds. For low-speed dry polishing on marble, travertine, limestone, glass tile and stainless steel.
Features
- 4" aluminum backer plate with built-in SFAT snail-lock adapter
- 5/8"-11 spindle thread — fits standard variable-speed grinders and low-speed polishers
- Required companion to Alpha® PVA QC discs — grit changes in seconds
- Maximum safe speed 4,000 RPM — for low-speed tools only
- Pairs with Makita 9207 SPC, Bosch 9250, AEG WP1900, Milwaukee 5460/5540/5455/5535, Alpha AIR-680, and similar tools
- Durable aluminum body for long service life in the field and the shop
| Part No. | Size | Thread | Type | Max RPM | UPC |
|---|---|---|---|---|---|
| PVA-5/8 | 4" | 5/8"-11 | Snail Lock (SFAT) Adapter | 4,000 | 749173040139 |
- Thread the PVA-5/8 backer onto your 5/8"-11 spindle hand-tight, then snug with the spanner.
- Confirm the tool is set to 4,000 RPM or lower (variable-speed grinders: lowest range).
- Press a PVA QC disc onto the SFAT adapter and rotate to snail-lock it into place.
- Run DRY only — PVA must never be used with water.
- To swap grits, untwist the disc off the snail lock and twist the next disc on.
- Polish in sequence: White (40) → Red (80) → #F15C22 (220) → Green (400) → Yellow (600).
4" — 5/8"-11 spindle thread; accepts PVA QC discs via snail lock — Snail Lock (SFAT) Adapter — PVA-5/8
| Part No. | PVA-5/8 |
| UPC | 749173040139 |
| Size | 4" |
| Type | Snail Lock (SFAT) Adapter |
| Attachment | 5/8"-11 spindle thread; accepts PVA QC discs via snail lock |
| Thread | 5/8"-11 |
| Max RPM | 4,000 RPM |
| Packaged Weight | 0.70 lbs |
| Package Dimensions | 5in x 4.5in x 2in |
| Commodity Code | 6804.22.0000 |
| Country of Origin | Brazil |
| Property | Detail |
|---|---|
| Diameter | 4" |
| Spindle Thread | 5/8"-11 |
| Type | Snail-Lock (SFAT) Adapter / Backer Pad |
| Maximum RPM | 4,000 |
| Body Material | Aluminum |
| Application | Dry use only with Alpha PVA QC discs |
| Commodity Code | 6804.22.0000 |
| Country of Origin | Brazil |
What does the PVA-5/8 actually do?
It is the aluminum backer/adapter that allows Alpha PVA QC dry-polishing discs to mount on your grinder or polisher. The PVA QC discs snail-lock straight onto its built-in SFAT adapter.
What spindle thread does it have?
5/8"-11, the standard US grinder/polisher thread.
Can I run it on a high-speed grinder?
No. Maximum safe speed is 4,000 RPM. Use a low-speed polisher or a variable-speed grinder set to its lowest range.
Which tools is it compatible with?
Any variable-speed tool that can run at or below 4,000 RPM. Common matches: Makita 9207 SPC, Bosch 9250, AEG WP1900, Milwaukee 5460 / 5540 / 5455 / 5535, and Alpha AIR-680.
Do I need anything else to start polishing?
Yes — the PVA QC discs themselves (sold separately, in boxes of 5, single packs, or a 5-piece assortment).
Can I use water?
No. PVA is a dry-only system. Water makes the PVA disc swell and disintegrate.
Does the adapter come in other arbor sizes?
Yes — call us for availability of optional arbor sizes.
Does it work with PVA MS or PVA VP discs?
No. The PVA-5/8 is the snail-lock adapter for the PVA QC ("Quick Change") system. PVA MS and PVA VP mount on their own backer hardware.
PVA QC Polishing Discs
⚠ WARNING: Cancer and Reproductive Harm — www.P65Warnings.ca.gov. Always wear appropriate PPE.











