Printed from Kezuriba (kezuriba.net/en/maintenance/drill-press/troubles/)
Drill press troubleshooting quick reference
Look up likely causes, what to check, and remedies from the symptom. Lubrication points, oil types and intervals, belt tension and speeds differ by model. The values here are examples from published instruction manuals; the manual for your own machine takes priority. Do not wear gloves while the machine is running (Ordinance on Industrial Safety and Health, Article 111)
Hole is crooked or tiltedCommon
| Likely cause | What to check | Action |
|---|---|---|
| Table (column) clamp screw is loose | Table clamp bolt, screw that locks the table height on the column | After setting the height, tighten the clamp bolt firmlyKira says that working with it loose makes the table tilt downward at the front and produces tilted holes[1][2][3] |
| The surface being drilled is not square to the table (spindle) | Workpiece top surface and table tilt | Level it, or make the surface flat in a prior operation[4](1 source, for reference) |
| Drill wanders at entry (no locating dimple) | Whether there is a center punch mark or center hole | Make a dimple with a center punch (Makita), or center-drill first and then drill (OSG). Increase the rigidity of the tool, workpiece and clamping[4][5] |
| Point angle of the centering drill is smaller than that of the main drill | Point angles of the centering drill and the main drill | Center-drill with a drill whose point angle is the same as or larger than that of the main drill. Do the chamfering and the centering separately[6](1 source, for reference) |
| Drill point is asymmetric (lip height difference, off-center chisel) | Quality of the regrind | Regrind correctly and check the accuracy after grinding (lip height difference 0.03 mm or less)[4][7](1 source, for reference) |
| Drill wear or insufficient rigidity | Drill wear, length and diameter | Regrind or replace it. Use a more rigid drill (shorter, or carbide)[4](1 source, for reference) |
Hole is oversize or out of round (polygonal, "rice-ball" shaped)Common
| Likely cause | What to check | Action |
|---|---|---|
| Large runout of the drill as mounted | Outer-diameter runout with the drill held in the chuck | Keep the runout within 0.02 mm (OSG). Tighten all 3 holes of the chuck evenly (Yukiwa Seiko)[8][7][1][9] |
| Large spindle play | Spindle runout and play | Inspect the spindle and have the manufacturer service it[4](1 source, for reference) |
| Poor regrind (uneven lip heights, off-center chisel) | Lip height difference, chisel position | Bring the lip height difference to 0.03 mm or less and revisit the web thinning[8][7](1 source, for reference) |
| Feed is too high (heavy cutting load) | Feed per revolution | Review the feed. OSG gives a guideline of "drill outer diameter × 0.02" mm/rev[8][4](1 source, for reference) |
| Drill wobbles at the hole entry | Shape of the hole at the entry | Increase the feed per revolution and steady the drill with thrust forceToo high a feed also makes the hole oversize, so judge it separately from entry wobble[7](1 source, for reference) |
| Workpiece is not clamped firmly enough | Vise and table clamping | Clamp the workpiece in a vise and clamp the vise to the table[4][1] |
Drill wobblesCommon
| Likely cause | What to check | Action |
|---|---|---|
| Oil, dirt, rust or damage on the taper of the chuck or spindle | Dirt and damage on the taper | Wipe the taper and re-seat it with a wooden mallet. A taper with a lot of damage or rust should be corrected by the manufacturer or replaced (Yukiwa Seiko)[10][1] |
| Chuck key is tightened in only 1 hole | How it is tightened | Tighten all 3 holes evenly, a little at a time[9][5] |
| A small-diameter drill is held in a large chuck | Drill diameter and the chuck's gripping range | Use a chuck whose gripping range is as small as possible[9](1 source, for reference) |
| Chuck jaws are worn (overtightening, tool slipping) | Jaw damage and wear | Replace the chuck. Do not overtighten, and do not apply a load heavy enough to make the tool slip[9](1 source, for reference) |
Drill chuck falls outCommon
| Likely cause | What to check | Action |
|---|---|---|
| Oil or dirt on the taper | Chuck and spindle (arbor) tapers | Wipe both tapers with a clean cloth before re-seating[10][1][2] |
| Not driven in firmly enough | Whether it was tapped in when fitted | Retract the jaws and tap the end face in with a wooden or plastic mallet. Do not use a steel hammer[10][1][5] |
| Taper has a lot of rust or fine damage | Taper surface | The chuck-side taper may be correctable by the manufacturer (Yukiwa Seiko)Kira says that if the chuck falls out and damages the taper, the spindle becomes unusable[10][1] |
Abnormal noise or vibrationCommon
| Likely cause | What to check | Action |
|---|---|---|
| Belt tension is too tight or too loose (slipping) | Belt deflection | Re-adjust the tension (an item in the maintenance section; Makita gives about 10–15 mm of deflection when pressed with about 5 kg)[3][1][5] |
| Belt is run at an angle | Whether the belt runs parallel to the pulley grooves | Re-seat the belt parallel in the same-step grooves of the upper and lower pulleys[3][5] |
| Bearing or motor fault | Abnormal noise, vibration or smell from rotating parts | Stop work and ask the dealer or manufacturer to inspect and repair it[1][2][3] |
| Spindle was accidentally struck against the workpiece or similar | Whether noise or runout has appeared since the collision | Do not keep running it; contact the dealer or manufacturer[1](1 source, for reference) |
Speed drops or stops, drill breaksCommon
| Likely cause | What to check | Action |
|---|---|---|
| Pressing the handle too hard | Feed force | Lower the handle slowly and moderate the force[3][5] |
| Belt is tensioned too tightly | Belt deflection | Reduce the tension (HOZAN says that too much tension lowers the speed and shortens the life of the belt and motor)[3][1] |
| Used continuously beyond the rated time | Operating time | Operate within the rated time and rest the machine for as long as it was used (HOZAN K-21: 15 minutes)[3](1 source, for reference) |
| Drill is worn | Cutting edge wear | Regrind or replace it[5][4] |
Chuck jaws will not open or closeCommon
| Likely cause | What to check | Action |
|---|---|---|
| Chips were blown into the chuck by compressed air | Jaw movement | Clean the inside with a cotton swab, or tap the body lightly with a wooden or plastic mallet to dislodge the chips[10](1 source, for reference) |
| Tool is stuck in the jaws or at the bottom of a keyless chuck | Whether the tool comes free | Ask the manufacturer for disassembly and repair (parts replacement)[10](1 source, for reference) |
Causes on the side of machining conditions and tools are covered in the Machining Troubleshooting Encyclopedia .
📚Sources
Items without a mark are those on which two or more materials from different publishers agree. Values and intervals are governed by each machine's specifications. The text is summarized in Kezuriba's own words.
- KIRA Corporation, “Bench Drill Press NSD-340 Instruction Manual (DOC1-NSD340-JOM-01-02, 2nd edition, 2024-07-29)”
- KIRA Corporation, “Bench Drill Press KID-420 Instruction Manual (DOC1-KID420-JOM-01-02)”
- HOZAN, “Instruction Manual, Desk Drill K-21”
- OSG, “Drill Technical Data: ‘9. Troubleshooting’ (reference material for FAQ No.721)”
- Makita, “Bench Drill Press TB131 Instruction Manual”
- OSG, “Machining Consultation Navi FAQ No.718: ‘Hole Position Is Unstable Even Though Centering Is Done’”
- OSG, “Machining Consultation Navi FAQ No.721: ‘Why are drilled holes triangular?’”
- OSG, “Machining Consultation Navi FAQ No.705: ‘What causes oversized holes in drilling, and what are the countermeasures?’”
- Yukiwa Seiko, “Drill Chuck Q&A: ‘Usage’”
- Yukiwa Seiko, “Drill Chuck Q&A: ‘Troubleshooting’”