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Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 12:42 pm
by mdfinder
Need a little help if someone can provide it. I have searched a while through the forum but had no luck finding much info. I was using my Mark V in drill press mode. That is the only mode I have used it since I bought it last summer. I hear loud snap followed by a grinding noise. Shut the machine down within a couple of seconds and took the powerhead off tubes and opened it up.
The snap ring on the end of the motor had come off and, of course, the big washer was down in the bottom of the motor housing along with the snap ring.
The motor was running smoothly, I had not taken the spring off at any time. The snap ring looks good. Any ideas on why the thing would pop off like that. I was running at low speed and have rarely ever run the motor at top speed. The only time I have run the speed up is just to move the sheaves full travel up and back just to cycle them now and again. I usually run the drill press at a fairly low speed.
So any ideas would be a help. Also can you buy after market drive belts? The belt got chewed up a little.

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 1:22 pm
by mdfinder
Forgot to mention this is a used unit that I am dealing with. I bought it last summer and cleaned it up with help from the forum and it has been running fine for several months, nice and smooth. Just wondering if the snap ring is prone to weakening over time, or if running the machine too slow puts too much pressure on the sheave spring etc.
Mike

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 1:36 pm
by JPG
Drive belts are available from the mother ship(belt unique in today's world).

The clip is a standard hardware item, but not readily stocked typically. Also available from Mother.

Yes slow applies max pressure to the spring(pulley sheave open)but that is not much more than fast.

The clip may have been hyper stretched by a previous owner.

Examine the groove for possible damage.

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 3:15 pm
by mdfinder
Thanks JPG I put the thing back together as I waited for a response and it is running smooth again, but I think I will get the clip and the belt and replace them. The grove looks good. The sheaves show a little wear right at the tapered tips, but I don't know how they should look so I think I will save the expense for now and just use them. I really am enjoying this thing and just when I get to where I count on it, she shoots craps on me. LOL.
It works so well as a drill press and I have also used the disc sander. Being able to back a piece with the fence and then bring the quill up to it using the quill stop, makes for some really nice even pieces. And drilling on the horizontal has come in handy as well.
Thanks for the help
Mike

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 7:21 pm
by RobertTaylor
FYI The motor runs only at two speeds. On or off. The spindle however runs at many speeds by the changing size of the pulleys. I see this misconception often. The motor is on or off only.

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 8:03 pm
by jsburger
RobertTaylor wrote:FYI The motor runs only at two speeds. On or off. The spindle however runs at many speeds by the changing size of the pulleys. I see this misconception often. The motor is on or off only.

:confused: :confused: :confused: :confused: Where have you seen this misconception? Even novices here understand the speed is changed by the belts.

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 8:22 pm
by ERLover
jsburger wrote:
RobertTaylor wrote:FYI The motor runs only at two speeds. On or off. The spindle however runs at many speeds by the changing size of the pulleys. I see this misconception often. The motor is on or off only.

:confused: :confused: :confused: :confused: Where have you seen this misconception? Even novices here understand the speed is changed by the belts.
John I had to hunt for it when I read it, it was in his initial post, a typo I am sure.
"I was running at low speed and have rarely ever run the motor at top speed."

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 8:40 pm
by jsburger
ERLover wrote:
jsburger wrote:
RobertTaylor wrote:FYI The motor runs only at two speeds. On or off. The spindle however runs at many speeds by the changing size of the pulleys. I see this misconception often. The motor is on or off only.

:confused: :confused: :confused: :confused: Where have you seen this misconception? Even novices here understand the speed is changed by the belts.
John I had to hunt for it when I read it, it was in his initial post, a typo I am sure.
"I was running at low speed and have rarely ever run the motor at top speed."
But that quote was from the OP not RobertTaylor who expressed the "Misconception". :confused:

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 9:03 pm
by ERLover
John, I think that is what RT was referring to, to my best guess.

Re: Mark V motor sheave sping popped loose while in use

Posted: Thu Sep 29, 2016 11:14 pm
by JPG
I think it was merely a slip of the tongue. However if not, tis an appropriate comment.