FAQ-SHANGHAI INDUSTRIAL TOOL SUPPLY INC

FAQ

  Q: I need to ream several holes with diameters that are close in size to each other. Can I buy an expansion reamer and adjust it to each hole?

  A: No! Expansion reamers are not adjustable reamers. The expansion screw should NEVER be loosened in an attempt to use the reamer for a size smaller than that to which the tool was originally finish ground. Expansion reamers are beneficial when the diameter wears down to the low limit. It can be expanded oversize, reground to size and re-cleared.

  Q: When reaming I am getting a poor finish. What can I do?

  A: This could be due to unequal chamfers, incorrect margins, excessive spindle runout, chatter, or any combination of the above. Try regrinding the reamer with equal chamfer angle. Also try regrinding the reamer with narrow margins for reaming lower tensile materials. Other things you can try are increasing the back taper on the reamer, reducing the speed and increasing the feed, use a power feed unless the material is hard, use right or left spiral fluted reamer, or grind a secondary lead angle immediately back of 45° chamfer.

  Q: When reaming I am getting either an oversize hole, a taper hold, a bell mouth hole, or a poor finish. What can I do?

  A: This could be because of misalignment or insufficient cutting action. Several things can be tried to alleviate these problems. Use a bushing - .0002"/.0003" over reamer diameter. If the hole’s location varies, use floating reamer holder. Increase reamer back taper. Also try a reamer with positive radial rake to reduce cutting pressure. This may produce slightly larger diameter holes.

  Q: When reaming I am getting crooked holes. What can I do?

  A: This could be because the hole was not drilled straight and a reamer tends to follow the hole. Try to correct the previous drilling operation. Also try increasing the reamer attach angle (chamfer angle) to 120°/180° included angle. Another option (as long as it is not a blind hole) is to use a left hand spiral, right hand cut reamer to straighten the hole.

  Q: When milling I am getting a rough finish. What should I do?

  A: Possible causes are dull cutting edges or the wrong feeds and speeds. Resharpen the tool to original geometry. Increase your speed. Also try reducing your feed.

  Q: When milling I am getting excessive wear on the cutting edges. What should I do?

  A: This could be due to poor chip removal, recutting work hardened chips, the incorrect carbide grade, or any combination of the previously mentioned reasons. Some suggestions are to increase your feed (should be over .001" per tooth) especially when machining ductile or free machining materials. Also try reducing your speed. Lightly hone the cutting edge with a fine grit diamond hone. Another option is to increase coolant flow.

  Q: When drilling I am getting a shorter expected tool life. What can I do?

  A: This could be due to drill dwelling or only one lip cutting. Be sure you are maintaining adequate feed at all times. Regrind your drill with equal lip heights and chisel in center.

  Q: When drilling the drill walks or drifts. What can I do?

  A: This can be due to unequal lip heights or a worn drill bushing. Try regrinding the drill with equal lip heights and chisel in center. Also try replacing the drill bushing.

  Q: When drilling my holes are oversize. What can I do?

  A: This could be due to unequal lip heights, excessive lip relief, a worn drill bushing, or a combination of the above mentioned. Try regrinding the drill with equal lip heights and chisel in center. Also try reducing the lip relief to provide smaller chisel angle. Also try replacing the drill bushing.