Post By johnoder
Took out several gears in the headstock of what would otherwise be a beautiful machine. Looking for a good supplier of replacements for these!
Uh, you know that most folks have no idea what sort of gears you are looking for?
Since you are so vague, just bundle up the gears, ship them to Rush, and they do their magic.
Whoever does this will blow out your budget, unless this is government work or a museum piece.
Get back to this thread in a year or so, let us know if the lathe was repaired, or scrapped.
Last edited by S_W_Bausch; 08-08-2012 at 12:57 PM.
Thanks for the input on the suppliers. The gears are straight cut. One looks to be a single spur gear and another has three spurs all on one blank that can shift back and forth. Does anyone happen to know if Mcdougals have DP gears or Module? Any help is good help. This machine is a working machine. The same machinist has run that machine for the last twelve or more years. He feels like his right hand is gone and I would love to sew it back on!
Good description of a cluster gear made on a gear shaper. Strange how people think something like that may be laying around down at the PT supply house in the just right configuration.
three spurs all on one blank that can shift back and forth
The following simple test will tell you if DP or not.
Measure OD (mic over no burrs or raised metal) (works best with even number of teeth)
Count teeth - add two to the count
Divide mic O.D. into the above sum
If you get very near to a whole number, it is DP
32 teeth, 2.120 diameter
34 divided by 2.120 = 16.037, or 16 DP
I assume these are headstock gears and so will almost certainly be hardened and could be ground, I do not know the manufacturer of the machine but if it was MADE in the US I would suspect you have DP gears. If you do the sums and post the results I may be able to help.
Another point is that the bore of the gears will probably be splined or keyed, the ops to reproduce this are expensive so you may be able to turn/grind the old gear teeth off and so preserve the bore then shrink on a ring and cut new teeth in that.
You have not told us what the problem is with the old gears, are teeth missing or isa the whole thing just noisy.
Give us more to go on.
IIRC old machines were built in Canada but later they were rebadged German imports. Too bad Arno does not post I think he worked for McDougal. At any rate the probability of fixing the machine at a "reasonable" cost is near zero.
Originally Posted by byawor
Practically speaking, one would have to work up a spreadsheet of all possible costs, rigging, etc. regarding replacing the machine, downtime etc.
If one takes a broad view of mass production manufacturing, the conventional wisdom is to quickly obtain a late-model machine with warranty, new bells, new whistles, knowledgable support organizations, parts availability, etc.
Cause it's cheaper and more productive that way, usually.
It doesn't feel right, but that's the way it is.
Are any of the gears still useable? You could set up a VFD to get the speeds you need, and use only the gears that are not damaged.
Thanks for all of the ideas on this. First, there are teeth missing not just damaged. Secondly they are hardened and ground with splined centers. Lastly although I am encouraged by the idea of a VFD on a VDF Mcdougal the input clutch cluster seems to have been bent. I won't be taking it apart for a while due to work ramping up and I don't like to take something apart and then leave it for a long period of time. Being as it is a VDF Mcdougal would it not be a metric headset?
If a VDF with the name, probably - if a Mac made to the original drawings by VDF, probably not - would require redesign.
Being as it is a VDF Mcdougal would it not be a metric headset?
If this is a situation where the options are:
Fix the machine.
Trash the machine and don't replace.
Trash the machine, and replace it.
If you must have a machine of this capability, (AND what is that capability?), then fixing it is most likely the correct option.
If you would go without, then, go without.
The machinist who misses it greatly, if he truly needs it, then fix it. Or is he the operator that feels a bit guilty about whatever happened?
If the C to C is hard to find, then fix it.
If it's a 13 by 40, or a 17 by 59, I can understand your difficulty of making a decision.
I am curious, how impossible would it be to replace it? Is it parked in a basement, up a flight of stairs, etc?
Is it 200 inches between centers?
I suggest you setup a spreadsheet, and try to determine really good reasons to give up on it, and really good reasons to fix it.
If you can't do a specific job for a specific customer, and they take ALL their work somewhere else, what happens to the shop?
The machine is a 20 swing x 80 centers and as I said is a gem of a machine. We could fix the machine by making parts ourselves but we are a general machine shop not a gear shop so our efficiency would not be there. We don't really do heat treatment and we don't do grinding at all. Wasn't sure is someone knew of a place to obtain replacement parts for these type of machines.
If you are obligated to have the gears cut, providing the blanks should help reduce costs, at least for a local shop.
Can't say if the big boys accept someone else's blanks.
You probably want to conduct a post-mortem and determine if this was a one-time event, or that model machine is known to have this weakness.
Yahoo seems to have various user groups, perhaps other McDougal user groups exist.
Might just have to see if I can make the blanks and then send them off. It breaks my heart to see a great machine go down for any reason at all.
Tags for this Thread