My Flange Clamp won't tighten properly

This sounds like a worm drive. Try going to this web site to order your part.
http://www.ereplacementparts.com/skil-shd77-f012sd7700-worm-drive-skilsaw-parts-c-130_160_7479.html
This is the part for the blade clamp washer $5
Blade Clamp Washer
This is the flanged plain washer $4
Blade Clamp Washer
and retaining ring $4
Retaining Ring 2610341359 for Power Tool eReplacement Parts

Be prepared to get wet. Remove the filler cap AND the plug in the top of the radiator. Undo the clamp ring on the bottom radiator hose and prise the hose off the flange. It is best to "back flush" with a hose pushed into the bottom flange (seal around with a rag) before replacing the hose and clamp.
Fill the system with new coolant through the top of the radiator then BUT NOT EARLIER, start the engine and top up via the header (expansion) tank. Check the coolant level again after running for a short distance and top up as required

Hopefully you can tighten it Sometimes the flange bends up or can break. Many a flange is not held down properly with good enough screws or the plywood has been rotting etc. If you can tighten it or loosen it then it has to be cut off with a recipricating saw or hacksaw and replaced.

There was probably a hole in the flange that you discarded that was used to put a pin/ nail/ bolt/ etc in from the body of the saw to hold that flange from turning while you did the nut up. Unless that hole is there you will have no way of holding the shaft to tighten the nut.

MAke sure there is not two reducer washers on the machine, sometimes the old one gets stuck on the back flange and when you fit the new blade it does not clamp properly.

If you use a nut, the arbor nut will not hold your grinding/cutting wheel properly and you'll use up threade the arbor nut needs to tighten. What you need is the clamping flange, Bosch part number 3603340501. If you have a tool repair center near you they may have one or can order you one. If not, you can get one on sites like www.ereplacementparts.com.

You really don't want to know, but since you asked......... Remove spring clamp around front of seal by prying under it and peeling it off. The easy part is now done. Peel away seal and stuff it inside drum. Look or feel for screw on clamp around seal thats still attached and loosen clamp screw. Peel seal off and remove. Wipe away any crud on flange. Install new seal starting at the top. Make sure top and bottom of it are perfectly centered. Push seal onto flange all the way around, feeling your way around. Once on and its centered properly reinstall clamp and tighten. If its the flat metal type of clamp do not overtighten or it may come off in wash cycle. Install outer seal to front and reinstall clamp by putting spring on first, wrapping rest of clamp around as much as you can, then holding one end of spring ( I use my knee or you can use small screwdriver) and using needle nose pliers grab other end of spring and stretch it while putting rest of clamp on. Have fun!

TURN OFF RADIO.DISCONNECT NEGATIVE BATTERY CABLE.WAIT 20 MINUTES FOR AIRBAGS TO DISCHARGE.YOU NEED TO REMOVE THE STEERING COLUMN COVERS AND LOWER INSTRUMENT PANEL COVER.REMOVE THE IGNITION SWITCH.REMOVE THE RETAINING NUTS AND LOWER THE STEERING COLUMN.THE LOCK ASSEMBLY IS CLAMPED BY TWO SHEAR HEAD BOLTS.USE A CENTER PUNCH TO MAKE A DIMPLE IN THE HEAD OF EACH BOLT,THEN DRILL THE HEAD OFF WITH A 3/16 INCH DRILL BIT.SEPARATE THE CLAMP AND REMOVE THE ASSEMBLY FROM THE STEERING COLUMN. PLACE THE NEW LOCK ASSEMBLY IN POSITION WITHOUT THE KEY INSERTED AND TIGHTEN THE BOLTS UNTIL THEY ARE SNUG.INSERT THE KEY AND CHECK THE LOCK CYLINDER FOR PROPER OPERATION. TIGHTEN THE BOLTS UNTIL THEIR HEADS BREAK OFF.TIGHTEN STEERING COLUMN TO INSTRUMENT PANEL FLANGE NUTS TO 108 INCH POUNDS.TIGHTEN THE RETAINING COLLAR CLAMP BOLTS TO 16 FT LBS.

Easy enough....

1. Be sure the guard assembly is securely attached to the gear case.

2. Put the backing flange onto the tool spindle

3. Place the depressed center wheel on the tool spindle as shown.

4. Thread the threaded clamp nut on tool spindle as shown.

5. Hold the tool spindle by engaging the spindle lock pin, and tighten clamp washer with wrench

No, the o ring should not squeeze out. When putting the top and bottom components together....

1. Make sure surfaces are clean...No lube!!!
2. Make sure o ring is clear
3. Install o ring usually on lower half but depends on model
4. Gently place upper half on lower
5. Place clamp around the halves (this can be tricky)
6. If there is a tension spring with the clemps, do not use it yet
7. Without the spring, insert bolt and start tightening the clamp
8. The halves should slowly come together
9. Make sure the halves and band are aligned
10. Once the top is on the bottom fairly secure, loosen the clamp and re-tighten with the spring this time till the spring is compressed with no gap between the colis on the spring. If you have two tightening clamps, do this at equal intervals.

I dont know the exact model you have, but this is a standard procedure... Good luck..