Starting the Mark V & pointers

[nuhobby]

Hi,

I know it's been discussed extensively before, but here is my take on "what are the safe speeds to start the Mark V":

(a.) If you will be changing SPT's, especially if the bandsaw will get mounted, be sure to turn the headstock speed to < "D" (slow end) speed before shutoff.

(b.) Otherwise the machine is generally tolerant of shutoff & restart at moderately higher speeds -- provided it's not heavily loaded. Judicious use of this capability can save some wear on the speed-changer.

(c.) My Own Emphasis: Note that the Sanding Disk is a high-rotational-inertia [heavy] load. This can play heck with the headstock if you start it at a higher speeds (belt slips, oscillations, etc.). In fact, after mentally playing back my last year's extensive shop work, I believe one such incident has lead to premature wear / tick in my idler bearing.


Other tips ....

- Don't overtighten the headstock lock ... it really doesn't take much to hold the headstock in position

- Don't overtighten anything. When in doubt, check it out (especially internal parts).

Comments welcome!

[drl]

I had my SS 520 only a short time and was doing everything "by the book." Seems I got the idea to "spin" the headstock lock till it stopped than an additional quarter turn to lock it. I found out the hard way when I raised the headstock to drill press mode. All OK till I touched the quill feed to drill a hole and the headstock dropped like a rock. I have never seen a hole drilled so fast. Fortunately no harm done but I now put an extra quarter turn or so on the lock.

[crousetrodomis]

Right on DRL,
I did the exact same thing last year!!! Thought the head stock was locked only to find it plunging about 10000000 miles an hour down the tubes with a spade bit chucked up. LUCKILY it went through my regular saw blade guard but did manage break that plastic peice directly under the table.......though I can not remember right off the top of my head what that thing is called. (I decided to leave it off after receiving a new one by mail) NOW, my SS has these key chains that i've got from mulitple airshows through the years that say "REMOVE BEFORE FLIGHT" on every lock......especially the big ones!!!!! (thats saved my butt multiple times since)

Nuhobby, this pic was from the last Indy airshow, just thinking about those tags reminds me of "UUUHHHHMMMMMM.........AIRSHOW........."

[charlese]

Yep! it takes a bit more than Spin + 1/4 turn to hold that sucker firmly, when in vertical position.

[nuhobby]

Hey Crouse,

I've been to that Indy Airshow too! Maybe 2005 was the last one I saw. I wonder if Nick could fly his Wright Bros. machines over to it?

[chrispitude]

I like the positive lock of the 520's main table carriage. It would be nice to have something similar on the headstock, although I suppose it's not realistic to go redesigning the headstock internals to do this, given that the current design's been around for a few years...

- Chris

[dusty]

I like the positive lock of the 520's main table carriage. It would be nice to have something similar on the headstock, although I suppose it's not realistic to go redesigning the headstock internals to do this, given that the current design's been around for a few years...

- Chris

But chris, they are similar. They both employ wedges that are pressed tightly up against the tubes to lock. The wedges are moved (in and out) by a threaded rod.

The primary difference is the amount of weight that you are holding.

[backhertz]

I think the answer is the lowest. Reason? If you put a band saw on & start up on high speed, I can guarantee you will not be able to shut off the headstock before the band saw blade shoots across your work area....