Arg - broken BT3100

[adauria]

Well, I used my BT3100 for the first time today. I set the blade at max height to cut a large 4x4, a job it handled admirably. However, when I tried to lower the blade it wasn't going anywhere... Turning the crank in either direction yielded nothing.

So I spent a good 30-40 minutes poking around under there. I tried lubing somethings up, etc. Here's the deal - the selection knob works fine (i.e. angle v. blade height), and I can change the angle just fine. But the crank just doesn't affect blade height when that selection knob is set to lock angle and adjust height.

The shaft moves a little bit and moves that first gear just a little bit, but once it meets any resistance (i.e from the inertia of the second gear, the on that sits on the worm and raises or lowers it) it stops.

So I tried taking things apart starting with the crank. I was able to loosen but not tighten that hex nut on the face that holds it in. I need to get the proper sized allen wrench - headed to HF tomorrow to get it. I hope that's the problem, i.e. that I just loosened that handle somehow.

Any other ideas? Anyone else ever have this happen to them?

Also, how dangerous is it to use the blade at its highest setting for the time being? I am done cutting 4x4s and need to crosscut some 2x6s. I am inclined to hold off until I get this fixed. Good idea?

-Andrew

[LCHIEN]

those cranks are notoriously hard to get off, I think they use lock-tite or similar to hol that allen screw on.
I don't think it will help much taking it off anyway.

I suggest you get my FAQ which has one section discussing elevation problems.
Very often it turns out to be the elevation screw (you can find this on the right side ) jammed by too much sawdust.

[adauria]

Thank you! PM'd my email to you.

Where is this screw? On the right side of the crank handle on the outside of the case (I only see a set screw there), or somewhere on the inside of the case?

Thanks again!

-Andrew

[poolhound]

When you try to turn it is it locked and wont move or does it move freely but to no effect?

[LCHIEN]

Thank you! PM'd my email to you.

Where is this screw? On the right side of the crank handle on the outside of the case (I only see a set screw there), or somewhere on the inside of the case?

Thanks again!

-Andrew

if you remove the right hand cover panel from the saw (be careful, the ground wire attaches this thing to the main carcass), you will see a vertical threaded rod ("the elevation screw") that is driven by the elevation crank thru a crown gear. THe motor housing rides this screw up and down to position the cut height.

Your first order of business is to clean this screw and everything attached to it, then lubricate it with a non-greasy dry lubricant that won't attract more dust.
The next order of business is to consistently clean the insides of the saw when used and better yet, attach a shop vac to the dust port on the rear of the saw so it won't happen again.

P.S. A couple more thoughts,
You say the crank turns but nothing goes up or down.
1. The handle has a square shaft, its' not likely to be slipping.
2, dust in the screw lift usually causes difficult raising, with resistance, not likely in your case, since the handle turns.
3. The most likely is that the lock lever for angle or elevation is not fully engaged, I would guess. Might be a dust issue.

[adauria]

Yes, exactly - the handle turns all day long, but it doesn't move the crowns!

I agree - must be related to engaging. I am going to poke around now. and see if I can figure it out. Wish me luck!

-Andrew

[poolhound]

Yes, exactly - the handle turns all day long, but it doesn't move the crowns!

I agree - must be related to engaging. I am going to poke around now. and see if I can figure it out. Wish me luck!

-Andrew

Andrew,


Could simply be the allen bolt in the center of the wheel is loose. it takes a 3/16" allen wrench (at least mine does).

[adauria]

That was my thought Jon. I was able to loosen the bolt the other night, but not tighten it as I didn't have the right allen wrench. I got the correct wrench today, but it didn't seem to help. I took things apart and tried getting them back to together (the front of the assembly), and now it's a mess. I can't get the thing to lock in the left position. Sigh... I only played with it for about 10-15 minutes and gave up for the afternoon. [I started cutting / drilling / sanding the pieces for my kids' sandbox I am working - using a circular saw, unfortunately].

Anyway, I now that they are in bed and I have complete a good chunk of work on the sandbox project, I am going to take another crack at getting this thing working. Thanks again for all the great advice!

Believe me if I get it going I will let you folks know.

-Andrew

[poolhound]

That was my thought Jon. I was able to loosen the bolt the other night, but not tighten it as I didn't have the right allen wrench. I got the correct wrench today, but it didn't seem to help. I took things apart and tried getting them back to together (the front of the assembly), and now it's a mess. I can't get the thing to lock in the left position. Sigh... I only played with it for about 10-15 minutes and gave up for the afternoon. [I started cutting / drilling / sanding the pieces for my kids' sandbox I am working - using a circular saw, unfortunately].

Anyway, I now that they are in bed and I have complete a good chunk of work on the sandbox project, I am going to take another crack at getting this thing working. Thanks again for all the great advice!

Believe me if I get it going I will let you folks know.

-Andrew

Take out the allen bolt and the wheel and there should be a spring inside so watch out for that. The wheel attaches to the shaft against 2 flats. So are the flats on the adjustment wheel OK or have they been rounded so it wont turn the shaft?

Assuming the flats are good and engage the shaft cleanly it should turn OK and you should be able to see whats going on inside by removing the cover as Loring explained.

[adauria]

OK gents, I did manage to get it working! You guys were both onto the right track, and indeed there was a 3rd problem I had created.

Here is what I believe happened. When I was cutting a 4x4 I probably over-cranked the handle beyond max height. This did 2 things - loosen that hex screw in center of the crank and stopped up the crown gear at the bottom.

I added the third problem when I initially was playing with the crank by loosening a larger hex nut where the outer part of the mechanism meets the case behind the lever. This caused the lever to be too loose to lock on the left side (that was today's new problem).

So I took the darn thing apart from the front, starting with the hex screw (this was about the 3rd or 4th time I removed it since trying to troubleshoot). I removed the handle, the spring, and that cylinder behind the crank where the spring fits into. I then realized the problem with the lever failing to lock had to be behind the lever. I used a smaller allen key to remove the small set screw (no small feat!). When that came out I saw the larger hex nut (there's a washer there too) was very loose. That problem was remedied easily enough by tightening the large hex nut, reattaching the lever and set screw. OK, so it could now lock but still would not lower anything.

So I tried to figure out if that semi-round (flat on 2 opposing sides) shaft in the middle was turning when I turned the crank. I reattached the handle and the stuff in between but didn't screw it in. The crank was turning but I could see that the shaft was not turning with it (when things were screwed on, the fact that the shaft was really stuck was causing that center hex screw to loosen every time, but not turn that shaft).

So I removed the right side of the case (minding the ground wires - thanks for that tip Loring!) and got a good look at the crown gears (previously I was crawling under the saw to look at - this was possible due to the non-standard casters that the previous owner installed raising the height). I cleaned them out a bit with a flathead screwdriver. There was definitely some sawdust in there, and since the saw was rarely used over the last few years things where just hardened and gummed up a bit.

I used some compressed air and - I know I'm not supposed to do this - some WD-40. I let that sit a minute and wiped up the excess. I didn't have any dry lube and was rather desperate at this point. I then took a pair of pliers to the shaft. It took quite a bit of strength, and some care not to strip it too badly. I finally budged the shaft, lowering the arbor ever so slightly. I worked it a bit up with the pliers, clearing gunk and remaining WD-40 out of the crown gears as I went along. Once it felt loose enough I reattached the crank and confirmed that I could now adjust the arbor up and down with it, and also checked to confirm that the bevel adjustment still worked. I reassembled the case and made sure everything was good and tight.

So you guys were both right - gummed up crown gears AND loose hex screw on the crank (as a result).

As for the shaft at the how the crank fits it, I must say it does seem rather easy to round them. I'm sure this little adventure probably didn't help any. Do you have any suggestions for making the flats on the crank / shaft fit any better? If they come loose again I'll probably rig them up with something or order a new crank.

Wow, I know a lot more about how that darn thing works than I ever wanted to know, but I suppose I am a wiser man for it.

Once again, you guys are great. I really owe you for fantastic advice. I will also read that FAQ cover to cover just to get that much better acquainted with the saw.

A million thanks, again!

-Andrew

[poolhound]

Glad you got it going. A PITA but as you say a good learning experience.

When you get time a trip to HD or lowes for some dry lube and then a good clean and lube will have everything working nice and smooth. You shouldnt have any more issues with the crank unless its already showing signs of serious rounding and it is put under stress again as with this episode. When the mechanisim is clean and lubed it should raise/lower/tilt easily.

[adauria]

Thanks Jon, I'll try and get that dry lube and give it a go. So far, so good!

-Andrew