Protimeter masonry drill bit, 3/4 inch, standard chuck
The masonry bit for drilling the holes used in Protimeter flooring moisture testing.
Specifications
| Part number | BLD34DR |
|---|---|
| Diameter | 3/4 inch (19 mm) |
| Shank | Standard chuck |
| Supplied in | Protimeter flooring kits BLD8800-FL and BLD7750-FL |
Hole size is not a detail
The sleeve has to fit the hole. Drill undersize and the sleeve will not seat; drill oversize and it will not seal, and an unsealed sleeve measures the room instead of the slab. Use the bit that matches the sleeve you are using — this is the 3/4 inch bit; for 12 mm sleeves use the 12 mm concrete drill bit.
Depth matters as much as diameter
In-situ testing standards specify the depth as a proportion of slab thickness. Fit the 3/4 inch stop collar so every hole is drilled to the same depth — judging it by eye across twenty test locations is how a survey becomes uncomparable.
The 19 mm hole set
Four items make a repeatable hole. Missing any one of them shows up as inconsistent readings rather than as an obvious failure.
- Masonry drill bit, 19 mm (BLD34DR) — drills the hole
- Drill bit stop collar (BLD34DRCLR) — sets the depth so every hole is identical
- Hex key, 5/32 in (BLD34DRCLR-K) — tightens the collar
- Wire hole brush, 19 mm (BLD4653) — clears the dust, which otherwise sits against the sensor and slows equilibration
All four are supplied in the HygroMaster 2 Flooring Kit.
Matching the sleeve, the hole and the sensor
Three sleeve systems exist and they are not interchangeable. The sleeve has to seal in the hole, or the air inside it equilibrates with the room instead of the slab and the test is meaningless. Match all three columns before you drill.
| Sleeve | Hole size | Bit | Sensor it takes |
|---|---|---|---|
| BLD4650 adjustable | 19 mm (3/4 in) | BLD34DR | Mini Hygrostick (BLD4755-5) |
| BLD4902 original, fixed | 16 mm | Not stocked — ask us | Full-size Hygrostick (POL4750) |
| BLD4750HS — not stocked | 12 mm | BLD12DR | Full-size Hygrostick |
The 19 mm system is the one supplied in the Protimeter flooring kits and the one used for in-situ relative humidity testing to ASTM F2170. If you are working to BS 8201 or BS 8203, check which sleeve the specification calls for before ordering.
Tell us which Protimeter you run and we will confirm the right part before you order.
