How to Tighten Up a Sloppy Second Hand Dremel





Introduction: How to Tighten Up a Sloppy Second Hand Dremel

About: Working my dream job in the Telecom industry, so chances are, i'll never have time to respond to comments or messages, nothing personal.

One problem with Dremel tools is that they don't always age gracefully, after a number of years of service they can develop a lot of lateral play in the spindle. Since the majority of uses for a Dremel place a side load on the spindle, it deforms the bearing mounts over time, I'll show you a quick trick to tighten them back up.

This Dremel I picked up at a garage sale had almost 1/16 of an inch of visible lateral play before.

Step 1: Crack It Open

Pretty simple, unscrew the annulus behind the collet and remove the four T15 screws. Pull apart the two case halves, remove the spindle/armature, and it's as apart as it needs to be.

Step 2: The Problem

Here you can see the problem, the back bearing is inside a rubber mount, probably for vibration purposes, and the front bearing is held in a little webbed plastic housing, over time the rubber softens and the plastic deforms, we just need to slightly increase the diameter of our bearings to make every thing tight again.

Step 3: The Fix

First peel the rubber boot off the back bearing, now cut some narrow strips of paper tape (masking tape, painters tape, whatever). Wipe the grease off the outside of the bearings, and wrap two to three turns around the bearing, replace the rubber boot and reassemble.

After doing this my Dremel now has no visible play in the spindle.



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    That's a neat thing to keep in mind. I bought a Dremel instead of a knock-off because they have bearings rather than bushings. Interesting to see that the bearings aren't what is wearing out, but the case.

    1 reply

    False. My several years old Dremel 370-5 has bushings, but they have held up fine.

    It has practically worn out its brushes, but not completely. I disassembled it because the speed adjustment potentiometer has loose wipers internally so it no longer spins reliably. They didn't put enough room in the casing for a good quality POT so now I contemplate taking the pot apart for microsurgery to its wipers and conductive traces, trying to find a drop in replacement which is unlikely, or must substituting a couple of resistors to make it a fixed, single speed tool. The latter is most likely what I will do, as a used dremel is not worth much more time or investment than 2 cent resistors I already have.

    I suppose the other option is make a speed controller box at the other end of the cord but meh, again it is probably more time than it's worth as I would get a good 2nd tour of duty out of it as a fixed-speed unit and a new one from a different brand with less profit margin isn't very expensive today.

    sorry guys dam this kindle and its predictive text! It's a draper rotary tool :)

    hi everyone I am in desperate need of help asap like now please!!!!

    I have a dealer rotary tool and im in the middle of a project that I am unable to finish as I need to change the saw I currently have in it

    It was working fine about a week ago until I changed the bit to the saw one that is in it at the moment (driving me mad) the collar thing you screw on when you have put the collet in is stuck and I can't budge it the button you press to stop it from turning when changing bits just pops out and it carries on turning please please please I'm getting really desperate now thinking of buying a new one but this is brand new a couple of months ago! So don't really want to buy another if this one can be fixed thanks guys for any help I can get

    Well, go figure.. Bad plastics allover the place. I have some sort of dremel clone, made by Einhel Bavaria (orange one, 135 watt, ~$33), but I compared it to an original dremel and mine is made of better quality and thicker plastic. Yet, the plastic wore out very fast... I already have it for like 5 years, and it has an annoying play very noticeable when I try to drill pcbs for tht components...

    What I did is to have the bearings surrounded by some narrow and thin strips of deer leather. The fact that the leather is so soft would definitely help the plastic, and leather is also good at protecting the plastic from future wear.

    As if this wasn`t enough, I still experienced some rattle which told me that instance that I have faulty bearings... So I purchased two sets of 606zz and 698zz bearings. It worked so smooth!!! I just had to press and gently knock the bearings off the shaft with a set of pliers and a hammer against a wooden block. They are just press-fitted. WD40 helps a lot, but make sure to clean the shaft before so that you don`t have debris jamming your press-fitted bearing on its way out.

    I have just seen this tutorial today (5th feb 2014), I really hope it will be better indexed so that it helps a lot more people. It took me quite some while to "engineer" the solution I applied, I almost bought a new dremel.


    1 reply

    Just wanted to add something more:

    If you are still unable to drill small holes like 0.5mm (drill breaks / hole turns out bigger) or if you are still unable to perform clean and narrow cuts (disk breaks / cut is wide), then it may also be a collet problem. It also happened to me, and I just remembered today: if you have "after-market" collets for your dremel`s chuck, these might have their body (the part that goes deep inside the chuck) narrower than you dremel`s inside pipe diameter. Just use some shrinking tube / painter`s tape and help it fit better.

    Don`t worry, the collet alignment help won`t wear out as it only helps you guide the collet through the chuck`s pipe when you insert it. Once you tighten up the chuck, it would be almost impossible to move it inside (unless excessive force is applied to your dremel also resulting in damaging bearings / bearing housings / body / tool).

    Drill well and be well!

    Thanks so much TUA.
    I've just done this to my dremel and it is now very smooth and sounds healthy.
    (It was very noisy - in 1st speed it was noisier than it is now in full speed)


    I just bought a "good condition" used Dremel 395 online, and when I turned it on it sounded horrible. My wife, said, "That sounds terrible! You aren't going to keep it, are you?" I mumbled something to her and thought, bad bearings. I was pissed.

    On my search for where to get bearings and how to replace them, I ran across your fix. Mine sure had more play than I could blame on bearings. Based on the "cost" of your fix, I gave it a shot on the front bearing only since the rear one seemed OK.

    Five minutes later the thing sounds brand new! You saved me a WHOLE lot of trouble! Thanks!

    BTW, the bearings seem to be in great shape. I wonder how many of these things got thrown out over the years for lack of a piece of masking tape.


    I use a flex shaft to carve a lot of stone and wood materials. I've already gone through two of them this year. Do you know where I can get bearings for them or how to replace them? the flex shaft is a little expensive, and I'm sick of replacing the whole thing.

    3 replies

    This is great !!!! thanks for shareing the link I live one block from a recycling center and the aways have things ti sale real cheap thanks to you I got a place to get parts thank you,,,

    I've no idea how to remove them, but if you can get them out and measure with calipers mcmasters carr is a great source for almost any sized bearing

    add  a bit of grease the bearings when u put it toether

    Always wanted to know what the insides looke like of the dremel. couldn't find anything on google images. ignore below. Inside Dremel. Inside a dremel. Repair dremel. Repair a dremel. Disassembled Dremel. Disassembled Dremel. Disassembled Dremel.

    I have a Dremel 395 that looks identical to yours and was just today thinking about checking it for runout before getting into doing PCBs. What luck that I ran across your Instructable! It is so simple that I didn't think it could help, but grabbed the thing, checked the end play, pulled it apart, did just what you said and the end play was gone! Turned out that the front bearing was REALLY loose in the housing. The bad news: I think the shaft is slightly bent since I still have some runout. Some? Maybe I should say tons! The longer the bit the worse it gets; maybe .020". Probably happened from all those years of just using it with the loose bearing! So now maybe I will buy a Proxxon for the PCB work...

    Awesome instructable. I use a Black and Decker RTX dremel tool, and even brand new it had a lot of spindle play. I use it for a CNC machine, so the dremel play really makes a lot of difference. If you want to make a new housing for the bearing, you should check out my instructable on sulpho-plastic. It is a very hard, metallic plastic that is super easy to mold and very cheap. It would probably work great for this.

    hahaha in bulgaria you can buy 1'st hand dremel for 15$

    3 replies

    I've fail to understand why someone who's response is for "$X you can buy Y" would post at a DIY site.

    No kidding. Lets through away a perfectly good tool so we can buy a new one.

    ohh man