Millwaukee 5625 router bearing pre-load

--- >>> UPDATED <<< --- Still, might be worth to read...

Thanks to Gerald (meet Gerald at MechMate forum), I found what I was looking for to get rid of the end play I had with my new bearings. The part is a wave spring and Smalley Steel Ring Co. had just the kind of on line documentation and catalog I was looking for to find the specific part.



I ordered the part through my local bearing reseller. I was a little concerned at first about the work load since I estimate the compressed thickness to be too tight on the router motor. I did got very good specifications regarding the Smalley wave springs but I couldn't get any accurate reading on the router motor regarding the room above the upper bearing and the motor frame (black plastic) where the bearing sit.

Upon assembly, the spring didn't seem too compressed and the test I made after reveal no problem. In fact, the bearing seem to be cooler than before!? With the shield bearing, it was already more cooler than with the factory sealed one but even at 18 000 RPM, the shield bearing was not even that warm to the touch. Those tests were made with without tool load (not cutting). I did read, on Smalley Steel Ring Co. web site, that they were actually proposing the wave spring to reduce bearing wear.

The following picture show how the wave spring is install. When the motor cover screws are tighten back in place, the bearings are now pre-load; their is a downward push effect that sit the bearing's balls into both the inner and outer races which, in theory, keep them from being "loose" (bearing clearance) between the two races. Pre-loading the bearings do fix the end play problem too which add to cutting depth accuracy... which I was looking for at first.





If you decided to go this route, once the wave spring is installed, test the router at the very slower speed first for the first few minutes then gradually raise the RPM and monitor the lower bearing temperature. The SKF shield bearing I installed (the lower one) is rate to up to about 18 000 RPM; I don't think it is wise to run the motor above that speed even if it can. When I ran my tests up to 18 000, I promptly removed the cover to monitor the upper bearing and it was slightly warmer than the lower one and I assume it is because the electrical rotating "connection" on the armature get quite hot.

As I post this, the bearings have been running with the wave spring for a weeks (say some 30 hours) and still cool so far and no end play what so ever.

Basic GIMP'ing; resizing an image with a few options

Resizing an image is a very common task and The GIMP as all you need a more to do this.
In this post I will assume that you already have The GIMP installed. If not yet, you can find the relevant installation information on The GIMP web site and follow the respective platform installation. You can get The GIMP and find all the information about it on it's dedicate web site and at many other place on the Internet like the official English GIMP user group (GUG). Just Google 'The GIMP' and you'll see how much information you can find about the GIMP.
The GIMP is free; both as "it cost nothing" and as in freedom. It's an Open source project under the GNU General Public License!

So here's the basic screen you get with a picture open with the GIMP. By default, three windows a loaded organizing the tools sets. The image is open in it's own windows. You can have more than one image open at once. It may be new to you to have this kind of windows organization but you should soon realize that when you work on images, you want all the space you can.



Before going further, once again, save your work on a different name. ALWAYS work on copy whenever you can so you don't mess up the original... safety first.





If you expand the saving menu, you get an enhanced interface...



Many file formats offer various options; in this case JPEG (*.jpg) has it's own. You can use the default setting but I find 'Progressive' option to be nice for web publishing. This option refer to the way the image is loaded by the Internet browser; non-progressive images open at full resolution from top to bottom while progressive start to load at low resolution but full size in the page. If you click on the images on this post, you'll see that I've saved those images with the 'Progressive' option checked.
The other "option" worth to mention is the 'Quality' slider on top. You can reduce the image size in term of disk space by sliding to the left. Check the 'Show Preview in image window' to see in real time the effect of the quality option slider. Of course, the more you slide to the left, the smaller your image file size will be but the image will start to loose it's resolution. I generally slide between the default (85) and 50 with the 'Show Preview in image window' checked to see how it look.



Now we're ready to make the resizing of the image. On the image's window menu, use the 'Image' menu to reach the 'Scale image...' dialog.



That will produce a dialog where you can specify all the size parameters, including Height, Width, and XY resolutions. Note the bit of chain next to the Width and Height boxes. You can click on that to link or unlink the height and width values. If the chain is intact, then the aspect ratio will be preserved. Let's assume that your image is 1280x960 pixels (4:3 aspect ratio). If you change the Width to 640, then the Height will automatically change to 480 (still 4:3) when you leave the Width box (by tabbing out or clicking another box). If you break the chain, by clicking on it, then you could make your image 640x500 (not 4:3), if you wished.



That conclude this post about resizing an image in The GIMP. The inspiration was to help some friends with their images publishing on forums. While at it why not introduce to some basic optimizations too!?
A lot more should (could) be covered about images formats, optimizing, web publishing and options related to their respective formats and I may very well post some more about using The GIMP for those.
There are a few more nice things I plan to post about using The GIMP such as nice way to watermark your images, image manipulations such as red eye removal and touch up of pictures and a cool one I recently learn about is making people Jedi knight (kids love that one)... stay tuned!

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Thanks to Denver Hull for his contribution on this post. Bot on Denver!

Milwaukee router 5625 bearings replacement

--- >>> UPDATED <<< --- Still, might be worth to read...

About a week after I've changed the brushes, the router went zzzzzzzzzzzzzzzzzzzzzzzzz... I sort of knew this was going to be some time soon!

I've managed to take plenty of pictures while replacing the bearings but when they actually failed, I hurry myself at disassembly to make sure of what parts I may need other than the two bearings. It was a Friday afternoon and I had to get the order on it's way. I was wise to do so since the collet shank (sometime referred as the chuck) had its inside threads damaged. Long story short; when I rebuilt the motor I've took care to take pictures that depicted the disassembly stage but I may have missed something too obvious to me.

The bearing can be purchased at your local bearing supply or you can get them from MK service center.



Once you have the cover, the electronic feedback module and the brushes off (that part is covered in my previous post about the brushes service), you need to tap out the motor frame (black plastic) from the motor housing (aluminum). Then you reach for the field insulator inside to have only the housing with the armature assembly still attached by the collet shank. At this point, you're ready to remove the collet shank and then press the armature out of the lower bearing. As recommend in the MK 5625 service parts list, you should soften the locking compound with mild heat to aid the disassembly of the collet shank. No need to make the collet shank red! Just make it hot; that's a few seconds while turning the armature at the other end. Be ready with your tools which should be 3/8" allan hex key and 1-1/8" wrench. There's (if your a lucky one) an inside hex fit for the allan key at the end of the armature shaft. The MK 5625 service parts list have very worthy informations regarding your tool; you can get it on the MK web site.



When the collet shank is removed, you need to press the armature shaft out unless there was no locking compound and it slide off with a hand pull which wasn't my case.



After that's done, press the lower bearing out of the motor housing...



The upper (small) bearing can be pulled off with the appropriate puller or if you're like me and don't have all the tool you may need some day, you can press it out... remove the tachometer first by pulling it out with your hand only.



That's it!... for half the work!

The next step is to clean the armature shaft where the bearings fit along with the lower bearing seat on the motor housing.

You need to install the lower bearing in the motor housing first. The lower bearing only needed to be slide on in my case, both in the housing seat and on the armature shaft in my case; you may need to press them in. Make sure the armature and the collet shank threads are surgically clean (screw on the collet shank dry prior to be ready; it should be easy to turn until it reach the bearing) and put two drops of locking compound on the threads 180 deg. apart when ready to screw on the collet shank. I decide to put locking compound on the housing seat too because there's only two small screw to retain the bearing in the housing once assembled. Screw back the two lower bearing retaining screws with the contamination shield (black plastic grid).

The upper bearing have to pressed in. Put back the tachometer with the help of your fingers only.



Don't forget to drop the field insulator back inside the motor housing before placing the motor frame back on the housing. Help yourself to align the upper bearing with your fingers...



The rest is pretty easy since it's just placing back the remaining parts. Again, I strongly caution about over tightening anything, mostly where you'll screw in plastic. I do recommend to run the tool at low RPM for the first 15 minutes without any load to set the bearings. Check for any overheating and abnormal sound.

Check out the complete set of photos that I've placed on my public gallery at Google Picasa Web Album. There's pictures of exploded views of the main components which layout the parts pretty much as they go inside. My armature shaft thread were damaged and I show how I managed to "repair" them.

Keep in mind that this is not any kind of "official Milwaukee service" procedure. I'm not neither an engineer nor a qualified electrician but rather the "average do-it-yourself handy guy". I only wanted to share this easy (for me) procedure to service this Milwaukee router motor.

The bearings are fairly cheap but I can say that I've decided to install something different from what MK provided. The bearings that I got from MK are sealed which can do the job but I've chosen to get a shield type to keep it cooler under high RPM. If you decide to install something else as I did, bring the original, or make sure you can provide the specs, to your local bearing supplier and either know what you do or discuss with the technician what is the best to get for the application as there's probably many bearing that can fit in but may not work in the long run. In fact, the critical specification to be cautious about is the clearance; enough but not too much...

The whole procedure take around an hour the first time I did it.

Let me know if something doesn't seem right or doesn't make sense (leave a comment or use the Get in touch link in the Links section) and I'll make it up to your suggestions and recommendations.

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I plan to try to find the proper preload spring for the upper bearing so I can get rid of the free play from the lower bearing clearance... I'll post if I find it.