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| Brand Name: | XRTOOLS |
| Model Number: | 98MM |
| MOQ: | 500PCS |
| Price: | $0.35-22/PCS |
| Delivery Time: | 30-35 days |
| Payment Terms: | L/C, T/T, D/P, Western Union, MoneyGram |
When specifications call for a 98mm (3-7/8″) opening, you've entered the category where ordinary hole saws fail dramatically. At this diameter, vibration multiplies, heat builds faster, and torque demands exceed what most standard tools can handle.
Our M42 Cobalt Series 98mm is purpose-built for industrial maintenance teams, electrical contractors, and tank fabricators who routinely cut large-diameter openings. With 8% Cobalt metallurgy and a reinforced backplate 40% thicker than standard saws, this hole saw delivers clean, round, accurate holes in materials that destroy lesser tools – including thick-wall PVC, fiberglass-reinforced plastic, aluminum plate, and even mild steel up to 5mm.
Unlike smaller hole saws, the 98mm faces unique challenges: slug weight, chip clearance, and breakthrough kickback. Every feature of this tool addresses those specific issues.
| Parameter | Value |
|---|---|
| Diameter | 98mm (3-7/8″) |
| Material | M42 High-Speed Steel with 8% Cobalt |
| Tooth Hardness | 67–69 HRC |
| Tooth Design | 4/6 TPI Variable Pitch (optimized for large diameter) |
| Cutting Depth | 41mm (1-5/8″) – deeper than standard |
| Max Steel Thickness | 5mm (single pass) |
| Max PVC / ABS Thickness | 12mm |
| Runout (TIR) | < 0.2 mm |
| Core Ejection | 5 enlarged speed slots (360° distribution) |
| Backplate | Reinforced steel, 4mm thickness |
| Arbor Compatibility | 1/2″ hex / 7/16″-20 UNF thread |
| Material | Recommended RPM | Lubrication | Feed Pressure | Notes |
|---|---|---|---|---|
| Stainless Steel (304/316) | 65 – 95 | Heavy cutting oil | Very slow, steady | Magnetic drill strongly recommended |
| Mild Steel | 130 – 180 | Cutting oil / paste | Moderate | Use pilot hole first |
| Aluminum (thick plate) | 220 – 300 | Isopropyl alcohol | Steady, not forced | Clear chips every 3mm |
| Schedule 40 PVC (thick-wall) | 280 – 380 | None or water mist | Light | Expect spirals, not dust |
| Fiberglass (GRP over 8mm) | 130 – 200 | None (dry cut) | Moderate | Vacuum dust – it's abrasive |
| ABS / Polyethylene tank | 250 – 350 | Water mist | Light | No melting if speed is correct |
| Hardwood (thick timber) | 300 – 400 | None | Fast | Back up exit side to prevent tear-out |
The 98mm diameter serves specialized niches where smaller and larger sizes don't fit:
4.1 Thick-Wall PVC Plumbing (Schedule 40 / 80)
Unlike standard hole saws that melt or bind in PVC, the 4/6 variable TPI clears chips aggressively. Perfect for creating 98mm branch connections in main sewer lines, irrigation manifolds, and industrial drain systems. The 5 ejection slots prevent clogging with PVC spirals.
4.2 Fiberglass Tank & Vessel Fabrication
Water treatment plants and chemical storage manufacturers regularly need 98mm ports for level sensors, inspection windows, and sample ports. Standard bi-metal saws dull quickly against fiberglass – the 8% Cobalt maintains hardness against abrasive glass fibers, delivering 4× more holes per saw.
4.3 Large Cable Entries (Main Power & Data Centers)
98mm matches common European and Asian cable gland sizes for main building entries. The reinforced backplate prevents warping when drilling through heavy-gauge electrical enclosures (up to 4mm steel). The burr-reduced finish preserves IP65/66 seals without secondary finishing.
4.4 Agricultural & Industrial Tank Access
Polyethylene and polypropylene tanks for chemical storage, diesel, or water treatment often require 98mm fittings. The variable pitch reduces heat buildup – critical for plastics that melt and weld themselves to the saw.
4.5 Marine Through-Hull Fittings
Many boat builders use 98mm for deck fills, holding tank vents, and fishfinder transducer mounts through GRP hulls up to 15mm thick. The 5 ejection slots allow quick core removal when drilling multiple holes in a single vessel.
4.6 Solar Farm Combiner Boxes
Utility-scale solar installations use 98mm entries for main DC combiner boxes. The precision balance ensures clean holes in thin-gauge steel enclosures without dimpling or distortion.
| Customer Challenges | Our Engineered Solutions |
|---|---|
| "At 98mm, the slug weighs over 200 grams – it never falls out cleanly." | 5 enlarged speed slots at 0°, 72°, 144°, 216°, and 288° distribution. Insert any flat screwdriver or punch to lever the slug out in 3 seconds – no hammering, no stuck cores. |
| "The backplate bends when I apply torque, making the hole conical instead of straight." | 4mm reinforced backplate – 40% thicker than standard 2.5mm plates. The saw maintains perpendicular geometry even under high torque from magnetic drills. |
| "Chip clearance is a nightmare at 98mm – chips jam between saw and material." | Deep gullet tooth geometry combined with 5 ejection slots creates continuous chip flow. For PVC and aluminum, chips evacuate upward rather than packing. |
| "I'm drilling overhead or vertically – the slug falls onto the bit or into the enclosure." | The 5-slot design allows you to reach through the saw from the side and catch the slug with a magnetic pickup tool or gloved hand. No dropped slugs into live panels. |
| "Breakthrough on large holes kicks back hard enough to sprain my wrist." | Variable 4/6 TPI reduces tooth engagement by 40% during breakthrough. Combined with reduced feed pressure in final 2mm, kickback force is cut by more than half. |
Q1: Why does the 98mm have 5 ejection slots when smaller saws have 2-3?
A: The slug from a 98mm cut weighs approximately 220 grams in steel (about half a pound) – heavy enough to jam solidly inside the saw. Standard 2-slot designs require hammering or drilling out. Our 5-slot 360° distribution gives you multiple leverage points, so you can pop the slug free from any angle with a screwdriver tip. For plastic materials, the extra slots also prevent chip packing.
Q2: Can I use this 98mm hole saw on a standard ½″ hand drill?
A: For thin materials (PVC, drywall, wood under 10mm) – yes, with a drill rated at 8+ amps and a side handle. For steel, aluminum plate, or thick fiberglass – no. At 98mm, torque requirements exceed what most hand drills can deliver safely. Use a magnetic drill press, a hole hawg (right-angle drill), or a drill press. Attempting stainless steel with a standard hand drill will stall, grab, or cause injury.
Q3: What's the actual cutting depth? The spec says 41mm but I need 50mm.
A: The saw body depth is 41mm (1-5/8″). For thicker materials, you can: (1) cut from both sides if accessible, (2) use a hole saw extension rod (sold separately), or (3) plunge, withdraw to clear chips, and plunge again – this works up to ~60mm total in soft materials. For steel over 5mm thick, we recommend annular cutters instead of hole saws regardless of depth.
Q4: How many holes can I expect in 304 stainless steel (3mm thick)?
A: With proper lubrication (heavy cutting oil, not WD-40) and correct RPM (65–95), expect 15–25 holes before noticeable dulling. Without lubrication, 3–5 holes maximum. With coolant-fed magnetic drill, some users report 40+ holes. Compare to standard M3 (2% Cobalt) saws that typically fail at 5-8 holes in the same material.
Q5: My 98mm saw is cutting oversize holes. What's wrong?
A: Three possible causes:
Worn pilot bit – the pilot bit centers the saw. Replace it every 50-100 holes.
Loose arbor connection – check that the hole saw is tightened fully onto the arbor threads.
Material flex – thin sheet metal (under 1.5mm) can deflect under pressure. Back the material with a wood block or reduce feed pressure by 50%.
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