Removing a Stuck Bit or Arbor

Bits and arbors become stuck on the motor shaft for a variety of reasons and with a little work can generally be easily removed. It is important to remember that the stuck bit or arbor is now attached to the most expensive and delicate part of your machine: the motor! It is not uncommon to succeed in getting the stuck bit or arbor off only to have caused severe and irreversible damage to the motor. For this reason, it is important to follow the removal steps below in the order they are listed - that is from least invasive to most potentially invasive! Followed in order and carefully these steps are useful for any machine whether from Inland Craft or other manufacturers. If the problem is a stripped or stuck set screw, skip to that section now.

If you are trying to remove a stuck bit from any grinder remove any work surfaces, BitSerts, and sponges first. If you are trying to remove a stuck arbor from a SwapTopô saw you need to remove the motor unit from base and place it on your work surface so the motor shaft now vertical.

Step 1

It is often the case that the shaft above where the bit or arbor was mounted has become crusted with ground material, debris, hard water residue, grime, grit, etc.. This residue might not even be obvious but has caused the bit or arbor to stick to the motor shaft.

push bit down on motor shaft ScotchBrite and steel wool use ScotchBrite or steel wool to clean motor shaft clean inside bit with paper towel if needed screw scars on round of motor shaft
  1. Completely loosen the set screw.

  2. Now see if you can push the bit or arbor further down onto the shaft. If you can, push it down as far as possible. If you canít push the bit or arbor down then skip to Step 3 now.

  3. With the bit or arbor pushed down as far as possible, inspect the motor shaft above it. If you see any burrs, small rings or curved marks (scars) on the round part of the motor shaft, skip to Step 2 now. If the shaft looks smooth then it is likely that reside, grime, or ground material is causing the bit or arbor stick. This can be cleaned up rather quickly by using a small piece of ScotchBriteģ (that green scouring pad) or a piece of very fine (0000) steel wool to polish the motor shaft.

  4. This is easily done by turning the machine on and then holding the pad or steel wool to the motor shaft as it turns for just a second or two to de-grime the motor shaft. Move the ScotchBrite pad or steel wool up and down the entire exposed shaft making sure to get all the way down to where the bit or arbor sits now. If the bit was stuck because of residue, grit, or grime, you should now be able to slide it up and off the motor shaft.

  5. Clean the bit on the inside (where it slides over the motor shaft) as it will likely have dried residue or grime in there. A wet paper towel can clean out most of this but if needed you can use the ScotchBrite pad or 0000 steel wool but be very careful, brass is much softer than the stainless steel motor shaft. It doesnít take much to widen the ID of the bit or arbor beyond spec.

You can now reinstall the bit or arbor onto your machine. The Prevention and Maintenance Tips at the end of this explains how to avoid this problem in the future.

Step 2

Burs and scars, those round marks, cuts or rings, are created when the bit or arbor is tightened to the round side of the motor shaft instead of the flat. The flat side on the motor shaft, which is added at great expense, is as the place to tighten the set screw against. You must always secure the bit to the flat of the motor shaft to avoid damage!

screw scars on round of motor shaft use ScotchBrite or steel wool to clean motor shaft clean inside bit or arbor with paper towel if needed polish entire motor shaft with ScotchBrite or steel wool secure bit or arbor to flat of motor shaft
  1. Turn on the machine

  2. Hold the pad or steel wool to the shaft where the burr is and move it slightly up and down until you see that the scar is polished out.

  3. Remove the bit and clean out the inside (where it slides over the motor shaft) to remove any accumulated residue or grime in there. A wet paper towel can clean out most, if needed you can use the ScotchBrite pad or 0000 steel wool but be very careful, brass is much softer than the stainless steel motor shaft and it wonít take much to widen the ID of the bit or arbor beyond spec.

  4. De-grime the motor shaft by turning the machine on hold the steel wool or ScotchBrite pad against the entire shaft for a couple of seconds. You can now reinstall the bit or arbor onto your machine. The Prevention and Maintenance Tips at the end of this explains how to avoid this problem in the future.

Occasionally you may need to enlist a more abrasive product such as very fine grit emery cloth or super fine sandpaper if the scar is deep. You must use extreme caution and be very careful as you can quickly damage the motor shaft if you are not paying attention!

Step 3

faucet or gear puller for removing stuck grinder bit or arbor

A bit or arbor that is stuck and cannot be moved either up or down on the motor shaft will need be removed using a device that we call a gear puller or that some call a faucet puller or plumbers helper. They are used to get gears or faucet handles off the post they are pressed on to. If you happen to own one of these yourself (they can be found for under $10) or know a mechanic or plumber that has one, great! If you donít you can usually walk into a plumbing supply store (with a smile) and they will do it for you while you wait.

To use, align the pullerís shaft onto the center of the motor shaft. Position the pullerís arms under the bit or arbor. As you twist the hand grip the arms rise along the pullerís shaft, lifting the bit free of the motor shaft. Be gentle and patient with this device and the bit or arbor will almost certainly come off.

Once the bit is off, inspect the shaft for burrs, scars, residue, grime and clean and / or polish as outlined in the steps above. Then clean / polish the motor shaft as outline in the steps above. Clean out the shaft hole of the bit as detailed in the steps above as it will likely have dried residue or grime in there. The Prevention and Maintenance Tips at the end of this guide explains how to avoid this problem in the future.

If you are unable to remove your bit or donít want to attempt the process, please contact Inland Customer Service during business hours for options and instructions to send your machine in for repair. Please DO NOT send a machine in without obtaining a Return Authorization Number first.

A Stripped or Stuck Set Screw

Generally a "stuck" or "stripped" set screw happens when the Allen wrench used to tighten and loosen the screw was not inserted properly and it has rounded the edges of this socket cup type screw and it no longer seats properly. It is very important you align the Allen wrench with the screw and insert it fully, making sure it is snug before you start turning it. To remedy the situation you can try the following:

  • If the bit is not on the machine, you can certainly turn the screw in further to the point where it falls out through the shaft hole in the bit. Replacement set screws are available from your supplier or if you have an old worn bit, remove the screw and use it as a replacement.

  • You can try using a small flat head screwdriver, like those used for eyeglasses, on a stripped set screw. It may be able to grab two "edges", allowing you to remove it. Make sure to replace it with a new screw so you donít have the problem again.

  • Some people have had success by putting a very, very tiny amount of cyanoacrylate glue (Super Glue) on the very end of an Allen wrench and then insert into socket cup of the stripped screw. You need to exercise great care to not glue the wrench or the screw to the bit. The goal is to glue the wrench to the set screw only! Let the glue set-up for a few seconds and you should then be able to remove the screw Make sure to replace it with a new screw so you donít have the problem again.

  • You can drill it out using an appropriate size bit made to drill stainless steel. Again, extreme care needs to be taken not to damage the motor shaft! WB-1 3/4", WB-8 1/4" and SwapTop arbors use a 8-32 3/16" cup screw; WB-9 1" bits use a 8-32 5/16" cup screw.

  • If the set screw is "frozen" in the bit due to corrosion you can try applying iodine (it can be found in the first aid aisle of most drug stores) or a penetrating oil or spray like WD-40 to loosen it.

  • To avoid this problem in the future, to remove bits from your machine when they are not being used for an extended period of time and make sure to store bits dry.

    Prevention and Maintenance Tips

    1. Make sure you use the correct bits for your machine. Most manufactures of these machine types, including Inland, have a .312" (5/16") motor shaft and their bits are made to fit that size shaft. Some imported bits are made with less exacting tolerances and some are made to fit a different size shaft. Both can prevent the bit from fitting and securing properly. Using the right bits or arbors for your machine ensures you will have a proper fit and avoid problems like a stuck bit.

    2. Always make sure that the bit or arbor is secured to the flat side of the motor shaft. Never secure the bit or arbor to the rounded side of the motor shaft.

    3. In the future, apply a non-water-soluble grease to the motor shaft to keep this residue out. Inland manufactures a product called Motor Shaft Lubricant for a few dollars, available from your regular stained glass supplier. It is specially formulated with Teflon for these wet applications. In a pinch, petroleum jelly (like Vaseline) will prove nearly equal to the task.

    4. Always remove bits and arbors from the machine when they arenít being used for an extended length of time, i.e. a week or more. This will keep the bit or arbor from seizing on the motor shaft.

    5. Develop the habit of inspecting the motor shaft, arbors, and bits for proper hygiene whenever you install or remove a bit or arbor.

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    removing a stuck bit or arbor (PDF)
    V2 04/2015
    Inland Craft Products, Co. ©2015