help with my bt3100

[mac2454]

Newbie here.
I just bought myself a used low hour bt3100.
Got it home and found that to raise and lower the blade is very hard, takes two hands.
Pulled sides cleaned and dry lubed all the moving parts, didnt help.
The unit is binding, if I put light pressure on the motor assembley the unit cranks down with two fingers.
Any suggestions for next step.
Thank You.
Mac.

[eezlock]

help with bt 3100

First, check to make sure the elevation mechanism is not in a bind somewhere.
The previous owner may have never cleaned the threaded rod from the handwheel to the trunion assembly, it may be caked with old sawdust and
gook left from cutting sessions. It would be a good time to use a soft brass
bristle brush or a good nylon brush and clean and lube everything up. While underneath the saw at this point, give it good look over and see if anything
looks damaged or is in need of replacement....probably not but it never hurts
to check anyway. If the previous owner cut a lot of pine and other softwoods
with a bunch of resin in them, the saw can get clogged up with junk pretty fast.
I clean and lube my saw underneath at least twice a year and am constantly
using the air hose to blow out all the sawdust from the saw when thru cutting,
it makes a big difference in how things operate!

[Uncle Cracker]

I know the shims aren't so much of a problem on the BT3100's as they were with the BT3000's, but I'd take a close look there for some kind of obstruction or misalignment, since pressing down on the motor seems to free things up...

[LCHIEN]

The following is on page 21 of the 47-page BT3 FAQ.

I'm having trouble with raising the blade...
I’m hearing a clicking noise when I raise the blade
What is this shim problem I’ve heard so much about?
Don’t force it! The BT3 elevation is usually a smooth-running mechanism, if you have to force it, stop and think – it needs cleaning or it is jammed; if you continue you will break the handwheel.
In order from least to worst possible problem:

The clicking noise is normal. This is the spring as it rotates on the keeper pin. Behind the adjustment handle. You can bend in the ends of the wire with needle nose pliers so it will not catch on the edge of the spring if it bothers you.

It’s very frequently the case that in reattaching the riving knife/splitter assembly, the two bolts have enough play that the riving knife leans backwards. When the blade is lowered, at some point the back of the riving knife touches the edge of the opening and drags, making it hard to lower the blade. Usually no damage done except to pride.

Your saw needs cleaning and lubrication; internally the dust has gotten to the point where the gears and elevation mechanism are jammed. Also lubricate the elevation screw shaft at the point where it engages the motor assembly and at the pinion gears. A good dry lube is generally recommended to prevent it from attracting and holding sawdust. Dust collection, the more aggressive the better, will help keep dust out the mechanisms in the future.

Occasionally you will have the dreaded shim problem (a BT3000/Sears 22811 quirk, this has been fixed in BT3100s). The shims are thin metal plates that ride between the motor holder and the saw frame when traveling vertically. They are normally held in place with the motor housing but can be deformed and fall out when the lubrication is not adequate. If you find some small metal plate below your saw body then the shim(s) have likely fallen out and will need to be replaced as they are the anti-wear mechanism. Vertical movement will become difficult. The shims are inexpensive but the labor can be a few hours. Keep your saw lubricated in this area with a dry lubricant. Johnson’s paste wax is good for this. A February, 2005 survey on BT3Central indicated that 70% of BT3 owners never had the problem but that 30% had some problem with shims. Replacement BT3000 shims: bent shims are part #969600-001
and the rear flat shims part #969599-001.
　
The BT3100 does not have the shim problem because the shims, though used, have a mechanical retainer. You can convert the BT3000 to the BT3100 shim system. The conversion is simple if you will have the saw apart to replace the belts and the cost is negligible
Parts List:
#969600001 Flat shim [BT3000/BT3100}$.90 ea, 2 needed
#0181010314 Spring shim {BT3100} $.86 ea, 2 needed
#0181010110 Guide holder {BT3100} $15.07 ea, 1 needed
#662329001 Drive belt {BT3000/BT3100} $13.49 ea, 2 needed
The parts are available from:
www.ordertree.com
www.billious.com
　
　
Sometimes the threaded elevation rod engages a threaded hole in the motor assembly and the threads are worn/stripped. You will need to enlarge the hole and thread a new helicoil (a stainless steel threaded insert) into the hole to repair the thread. See these elevation rebuild instructions by JohnG.
[posted by "Knuckles" Brian] I went the HeliCoil route. Thanks to Ed's instructions in the Article section, it wasn't too difficult. It's not something I'd want to do every day. I searched about a dozen auto parts, hardware, and machine shops in this area, and I had no luck finding the 9/16"-12 Helicoil (or clone) kit. I ended up ordering one from a website called Cartools.com. It cost something like $50, shipping included. Wouldn't you know, though, after I bought it I stopped in a local discount tool place that I hadn't noticed previously; they had a clone (Permacoil) kit for $15.
The next problem was finding a 19/32" drill bit to drill out the lug that the threaded rod goes through. …
Probably the most tedious (and potentially disastrous) step of the repair was drilling out the hole prior to tapping it. I figured that I only had one shot to drill the hole on the same axis, and I wouldn't know how well I did until "the reckoning" of trying to put it together. I used a 1/2" drill bit to help get the bit centered, and find the axis. I didn't measure the angle, but it wasn't exactly 90º to the table. I had to shim it with some laminated air and a few mosquito wings.
Once I got the hole drilled and tapped, the insert went in nice and easy, and I epoxied it in place. I made sure to keep screwing the insert tool in and out so that any epoxy that squeezed into the inside threads was "threaded" in.
I learned something during assembly that's important to the instructions. Install the threaded rod and bevel gears before tightening the screws that attach the motor housing and the guide holder. …
So, long story longer. . . . I was successful at installing the Helicoil insert. I've noticed that there is considerably less "play" in the mechanism, even less than when it was brand new. It's firmer and requires more effort to turn the handle, but not "won't raise/lower right" firm. It still feels like the Play-Skool handle is going to snap. Even though Ryobi Tech Support knows about the issue with the "soft" threads, I'm still going to send a note expressing my opinion that they should "toughen" that part up.
　
Factoid: the blade raising mechanism has a 12 TPI thread – it takes 12 turns to raise the blade one inch, or .0833" per crank turn. On my saw you can crank it exactly 12 turns one way then exactly 12 turns back and it will come back to about +/-.005" of where you started.