Changing Z-Axis Timing Belt on Boss 6

[snakebit95]

Does anybody have an exploded diagram of the head for a Boss 6 they can share? I need to change the timing belt on the Z-Axis. The teeth on the aluminum drive pulley were almost totally worn-away, and the belt is in the same shape. It looks as if the entire spindle assembly will have to be removed. Can anybody that has done this replacement confirm? Any tips / lessons-learned to share?

Rant......Now I think I know why gear-manufacturers do not recommend using a 13-tooth .5" pitch pulley!!

Thanks,
Wayne

[machintek]

I just replaced a broken belt on a V2XT. I took the belt housing off as a unit (heavy). I had to remove the quill and ball screw up as an assembly thus all relevant switchs, wires, switch dogs, etc need to be taken out of the way. Do NOT let the ball screw come out of the ball nut! I would say that this is not a one man job.

George

[snakebit95]

Thanks George!! I may have to buy lunch or beer for a buddy then. I had the entire head torn-down to the point where I could see the spindle assembly bolted to the head. Unfortunately, I had not noticed the worn belt / pulley until I had it back together. If I remove the bolts from the spindle assembly (6 from recollection), will the entire assembly lift-up? Did you have a lift to remove it, or did you man-handle it? Just curious as to how heavy the assembly is.

[snakebit95]

BTW....would you happen to know what the belt length or part number is? My belt does not have a part number on it, and I would like to order one before I tear it down.

Thanks again,
Wayne

[snakebit95]

OK......I disassembled the head this morning and removed the belt. Here are some steps I used to remove it. I hope this will help other members faced with the same task in the future.

1.) Remove top cover / variable speed adjuster (as an assembly).
2.) Remove spindle drive belt / pulley's.
3.) Remove High/Low gear belt-driven section.
4.) Remove actual High/Low gear section (this part is HEAVY). You will need to lift it high enough to slide a couple 123 blocks between the head and the assembly. You will need at least 2" of space to access a lube-line before removal. If you do it by yourself, you had better have some strong arms and a strong back!!
5.) Disconnect the lube line at the tee, so that you can finish removing the High/Low gear section. Careful lifting this. It is HEAVY!!!
6.) Remove the upper limit and home switch. I left the wires connected and let them hang in the front of the machine.
7.) Rotate the Z-Axis pulley until you have approximately 3" of quill hanging below the head.
8.) Place (2) 4 X 4 wood blocks stacked on each other under the quill and raise the table until the wood blocks just touch the quill.
9.) Remove (4) bolts from the top spindle plate, and remove the plate.
10.) Slowly raise the table using the hand-crank. The entire spindle assembly will lift above the head and allow you to remove the belt.
11.) Install the new belt and slowly lower the spindle assembly using the table hand-crank; watching / guiding the belt into the head so that it does not get pinched / damaged.
12.) Reassemble in reverse order.

My machine required a 27" long X 3/4" wide H-type timing belt (54-teeth), which I ordered from McMaster Carr (Part #6484K103).

I probably missed a few minor details; but this should get you close. Hope this helps somebody in the future!!