February 8, 2022

Why is my Dremel getting hot?

Why Dremels get hot

Dremels get hot when spinning at 5,000 to 35,000 RPMs. Even if you use it for a short time, when it gets to 10,000 – 15,000 RMPs do not be surprised when it gets hot. Do not block the air vents. If the Dremel is overloaded, it will burn up, and the accessories can burn out quickly as well if pushed, leading to a breakdown if you continue using it.

Troubleshooting tips

  • Assess the situation
  • Start disassembling the tool.
  • Start with repairs
  • Reassemble the tool
  • Screw the case shut.
  • Try it out.

We will explore these in more detail below.

Common reasons for Dremel getting hot

Dremels overheat due to blocked vents and prolonged use. It can be a technical fault on some Dremel parts, and excess pressure. That makes the Dremel tool break down, burning out hence the importance of making regular checks when it comes to the motor. If there is damage and continuity, remove the Dremel motor.

When your Dremel, the motor overheats, ask to do something like mixing mortar. You would have asked your tool to do a task beyond its capabilities. Fix it by upgrading the Dremel tools if you want to keep doing that process.

If your tool bit is dull, the Dremel needs to work harder to cut through wood. It happens when trying to cut through hardwood and check if you are working with a dull bit, replace the bit with a new bit, and see if the problem goes away. If yes, then the problem was the bit.

If you look on the side of your tool, there are air vents, where the smoke comes from. Just like any vents, these get clogged. It can be because they have been around plenty of sawdust. This causes hot air trapped by the motor, which will help the Dremel motor overheat, including a blow-dryer.

Dremel flex shaft getting hot.

Flexshaft overheating leads to melting. The fault is caused by incorrectly assembling the flex shaft core when putting the machine together.  If the flex shaft is assembled in a way that the steel core is subjected to compressive forces, it overheats. The core is the rotating part of the flex shaft.

Overheating can also be caused by:

  • insufficient or incorrect lubrication,
  • a sheath not within the wire guide,
  • a non-free floating flex shaft core,
  • or by a damaged spindle assembly.

Dremel 4000 overheating

The Dremel 4000 commonly overheats when ventilation slots are covered. When overheating, check the four vents on the tool to ensure that they are not covered or blocked. If the vents are not covered up, but overheating continues, it can be dust. That dust has accumulated inside the case and has to be cleaned out. There is a guide on opening the casing in the manual.

If the ventilation is not blocked, it can be a faulty bearing assembly. If the Dremel is overheating, check that the fan on the bearing assembly is functioning. If not, replace the bearing assembly. With the Dremel tool, the armature and bearing assembly are replaced at once, and there is a guide to show how this is done.

Dremel overheated and stopped working

Check all the parts. Start with the motor and unplug the tool. See if the shaft spins freely, you may have a bearing problem. Free up a bad bearing with light oil. Noisy bearings mean mechanical damage and, the armature will need replacement.

Dremel oscillating tool gets hot.

Dremel oscillating tool gets hot when it is spinning at 5,000 to 35,000 RPMs. Even if you use it for a few minutes do not be surprised that it gets hot. When running it at 10,000 – 15,000 RMPs it gets hot, do not block the vents. If the Dremel is overloaded, it burns itself up to be prepared to get the accessories burning out if pushed.

Dremel keeps shutting off.

Assess the situation

First, unplug the tool and assess the situation. See if the shaft spins freely. If it does not, you have a problem to fix. You can free up a bad bearing with light oil, but noisy bearings mean mechanical damage. If the bearings are bad, the whole armature will need replacement. If it does, next check the brushes. These are small blue screw caps on the tool. Remove them and have more carbon bricks left. The Dremel tool might come out while the other separates from the spring and remains in the brush holder.

Start disassembling the tool.

Remove the hanging clip and the body screws, and differ in size. Separate the body halves making sure that no small parts fall out, like the shaft lock assembly at the nose of the tool. Remove the motor assembly from the body, make sure which side is up concerning your dis-assembly order.

Start with repairs

Use a rounded tool like a screwdriver shaft and push the stuck brush out of the brush block. Check for damage, and when there is none, you will be able to re-use the Dremel brushes and brush block. Dress any warped or melted plastic with a needle file or sandpaper.

Reassemble the tool

The brushes go in last and worn brushes should be replaced. The brush holder connects to the motor assembly through friction fit contacts. Press them into place, reattach the rubber spacer to the rear bearing and place the motor into the housing.

Screw the case shut.

Look for a dark line on one edge of the brush, and install it in the direction of the arrow. The dark line in the direction of travel and install the brush caps. Plugin the tool and test if it does not spin, have a burned-out switch. Replace it, and the Dremel switch is available online at different prices. It starts working better than ever.

Dremel 200 overheating

When Dremel 200 is overheating, it could be the fuse between the brush and the variable speed control switch. The fuse might have blown. Replace the fuse without having to buy the complete speed control unit. If yours is still under warranty, you could send it back.

Dremel 3000 overheating

Check to see if the shaft spins freely, otherwise, you may have a bearing problem. Sometimes free up a bad bearing with light oil but noisy bearings

Dremel 4300 break-in procedure

  • Check brushes first, and after 50 to 60 hours of use, the carbon motor brushed will likely need to be replaced.
  • Unplug the tool.
  • Open the brush caps and remove the carbon brushes from the holders. Brushes need to be replaced in pairs even if one tool brush is more worn than the other. Refer to your owner’s manual for more information on motor brushes and replacement instructions.

​​Why is my Dremel so loud

Sometimes your Dremel gets loud, even when it is not cutting into material, and shows something is wrong with the tool. Dremel bearings are need greasing. Grease them to prevent them from drying out.

Dremels are not supposed to be too loud. The Dremel tool comes with its bearings and is always quiet. The loud noise removed when using a Dremel tool comes from cutting into materials, such as wood and metal.

Brushed universal motors are made noisy. When using one, expect to get some irritating noise. Dremel tools get noisy, as they spin from 5000 to 35000 rpm. The more speed you are using, the more noise produced.

David D. Hughes
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