Sears Craftsman 3" Dustless Belt Sander 315.11750 Timing Belt Replacement

 

Just a quick how to for those that have the Sears Craftsman 3 inch Dustless Belt Sander model 315.11750 on how to change the timing belt if you don't know how to already. Then again, I take if you already know to change it, you wouldn't be here...

It's not that it's difficult to change the timing belt. It's more a matter of getting to the timing belt.I looked high and low for the manual to find out how and couldn't find one online. I even called Craftsman who was supposed to send me a PDF copy of the owners manual but haven't at this point and are due another call...

Once you know how to get the cover off, its easy as pie. It took me two days to figure it out given the one I just purchased used which was covered in saw dust. Sadly neglected. More than I possibly knew in fact once I got it opened up. Though I already took out some of the screws needed to change the timing belt, you can take a gander at it pretty much as I received it in the image below:

This thing was screaming for lube- which I tried to do with some WD40 though the vent slots where the timing belt is trying to reach the back spindle but as I was to find out, this area was so packed full of saw dust, all it did was soak up the lube and then break the belt. So the timing belt had to be replaced. 

And by the way, yes, you can still get replacement timing belts for it. But I couldn't right off figure out how to get the dang cover off to replace it. I had taken out all the screws once could see but something was still holding it on. At the same time I thought something might be stuck since I couldn't see anymore screws to take out. Luckily, or thankfully, I didn't try to pry the cover off and break something.

Well, I'm here to tell you I figured out how to get the dang cover off. And I'm even going to show you how it's done so you can replace the timing belt on yours! Such a deal!

What you'll need tool wise is:

A Philips Screwdriver #3 though a #2 might work for you.

A small # 2 flat head screw driver.

A pair of Needle nose pliers.

You need the key to it all - A long reach 2mm or 5/64ths allen hex key. Check to see which fits yours best. A short reach or standard length allen key will not work. You'll never get to the allen set screw. It has to be what's called a long reach allen wrench or allen key. They're just longer is all.

That's it.. with those four tools you can pull the cover off and change the timing belt.. 1-2-3-4! So lets get into it shall we...

In total there are 4, yes 4 machine screws that hold the cover onto the metal frame. There are 2 coarse screws that hold the cover on the fan. Though this isn't all of them, here's what the two look like:

Don't mix those two screws up. The fine thread machine screws go into the aluminum body and the coarse thread are for the plastic. You mix them up and put a coarse thread into the aluminum body you won't get the right screw to hold again. You'll mess up the threads so be warned!

 And there is one allen set screw on the fan. And one snap ring. Ahh! Bet you didn't know about the set screw did you. And it can be a bitch to find. It's on the side of the fan at the top in-between the fan blades.

Anyway take out the screws you can see and set them aside.

Take the cover off the fan... you should be at this point:

Remove the snap ring and washer from the fan spindle;

See the set screw in the picture above? If not here's a closer look...

Next you need to loosen (not remove) the allen set screw in the side of the fan. Turn the fan so you can access the set screw through the fan exhaust port. (where the dust bag/vacuum hose attaches) like so...

Once that is loose you can or should be able to pull the fan out. If not, and it's stuck you can try putting something under the fan like a paint stick or something and tap it loose with one of those screw drivers with a removable drive insert... Like one of these:

Use the side that is big enough to fit over the spindle of course. Take the drive insert out, prop the fan up a bit and give it a few taps to break it loose. You may or may not have to do this. Depending on how your sander was cared for or not cared for. I had to... this time! lol

Pull out the fan and it will reveal a hidden screw - the fourth machine screw!

Once you take that out, you can now remove the timing belt cover and get to the timing belt. Mine as I mentioned was packed full of crap. Hard to tell from the pic but it as thick in there.. soaked in WD40 I had sprayed in there prior. What a mess...

Of course once you have it opened up, you may want to take the time to clean things up a bit and lube and grease things.

Cleaned up - mine didn't look so bad anymore...

You'll notice to the bottom right of the above image I took the fan spindle off. You can do what you want but I choose to coat the spindle with some high temp red bearing grease (with lithium), clean the needle bearing inside the spindle and repack them with grease before putting it back on. Not a lot on the spindle itself, just enough to coat it as you don't want it all over inside there getting on the belt etc, etc. And yes there's a bearing in the spindle, see...

Also you see that larger gear/pulley in the center of the timing belt area, you need to get some lube under it to it's spindle. There could be a bearing in there somewhere as well. I haven't taken mine apart that far yet to know for sure. In the mean time I used a high temp 20 wt turbine oil dripped under it to get to the spindle itself. Just keep working it till you know its down in there. Clean up any that is in the belt compartment before closing it back up. You don't want oil and grease on the belt or pully faces.

A note here: IF you took the fan spindle off, you have to put it back on before you put the timing belt on. Or you won't get it back on. At least not without a fight. I didn't try to force it but, it ain't going on easy if you have the belt on. Fan spindle first then the timing belt.

Replacing the belt - some say put it on the small pully first, others the large pully first. For me I found it easiest to put it on the larger pulley first and work it onto the small pulley. Whatever works for you as long as you get it on. It's not that hard.

Once the belt is on and you're happy with things, just put it all back together in reverse order.

And so all that need it, have it...

The original belt has a part number on it of - 852:622827:00

I picked up a pair of belts fairly reasonably priced from ebay. The ones I received had D&D Synchro Power Belt 116XL on the belt.

I'm sure there are other suppliers/brands that carry the same belt. I don't know as to the durability of this belt but they fit and it works fine now. I have an extra one as well if this one breaks or needs replacing. How long it will last, time will tell. I'm hoping I'll get some more use out it before it needs replacing by doing a few other things to mine while I'm working on it.

While on the subject of the sander, I also took apart where the platen goes just to clean it up. It defeintly needed some TLC...

As for the platen itself, it was completely shot. The metal cracked, torn and rusted. The cork worn out and crumbling...

Not being able to find a source for a replacement metal platen or cork for that matter I decided to make my own and make what I felt an improvement. As far as the metal platen, rather than make one from standard or stainless sheet metal, I opted to go with graphite impregnated canvas. I remember seeing them on the belt sanders in highschool shop class. They say they're good. I have seen I think teflon ones as well somewhere that I remember.. but I found the graphite impregnated canvas easy enough. So that's what I went with. That may extend the belt life as well. I don't know for sure.

As far as the improvements, I went with a thicker cork and I made the platen the full length of the base. The original was considerably shorter than the backer base. I didn't like it. The original cork was probably a 1/32nd thick and I was going to use 1/8th thick cork but with the graphite canvas it proved too thick to use with the stock screws. So I went with 1/16th inch cork.

I can tell you from first hand experience now, if you are going to use graphite impregnated canvas, when cutting it or working with it, I suggest you cover your work surface with newspaper. Think Michael Jacksons glove... You'll have silver graphite glitter everywhere as anything not stuck to the canvas sheds off. And like pencil lead, they mark things up if you swipe them off with your hand. Use a work bench brush and sweep them right into the trash if they get on your bench and they will. The last thing you want is your better half or a lady friend upset because her newly painted floor has pencil marks all over it as you scuff the graphite glitter with your feet... just saying in hopes of sparing you the grief.

One other thing I ending up doing to mine, and you may not have to yours, was adjust the platen hold down bar. I circled it so you know what I'm talking about...

Mine was sticking out too far past the base, to the right in the photo, the left on the tool. What this meant was I wouldn't be able to sand flush along upright corners. It wasn't sticking out that much, but enough to interfere and prevent putting that side up against something and getting right to the edge. So I used what I had, some needle files and lengthened the screw holes enough to move it to be flush with the base. Took a little doing with the needle files, but it worked.

Put a 80 grit Zirconia 3 x 21 inch belt on it I picked up from Harbor Freight today, a type I haven't tried before that is suppose to be for metal, fiberglass and wood and suppose to be self sharpening and last longer, though I don't know if all that is true to it's claim. Plugged it in and pulled the trigger. It runs just fine now, tracks true and holds tracking so I'd say it was a successful repair overall.

Of course I did an over all cleaning to start, okay, maybe a little more in-depth cleaning than some would do... lol I polished the plastic as best I could, removed all the screws and gave them a quick wire brushing to remove surface rust with my Dremel. I fixed a spot in the cord where someone had sanded through it. I wanted as a new owner of this tool to start with it as clean and like new as I could bring it.

I still need to pull it apart and give a light sanding to the armature. The brushes are good but it's sparking a bit more than I like to see on one side. It's old, been used a bit, definitely neglected and just needed some TLC to bring it back to working order. And if I take care of it, it should last me a bit.

Took a little time and effort but it looks and runs a heck of lot better than when I got it that's for sure! And with that, I finally... yes finally have a portable belt sander that actually works! The one I traded last year I posted about turned out to broken and I haven't been able to fix it though I certainly could have used it a time or two this year on some projects. Be that as it may, I have one that works now. And that's a good thing!

By the way, if you or anyone you know has a manual for the Craftsman 315.11750 and wouldn't mind scanning it to PDF and sending it to me, or if you have the PDF and can send it to me, I'd appreciate it. You can contact me via the contact button on this blog or my site.  I'll host the file and post a link so that anyone that needs it can download it.

At least you now know how to change the timing belt if you or I don't come across the owners manual. Hope that helps you some if you have this belt sander.

Till next time,

Stay Happy, Stay Creative!

cheers...