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Questions about a Gorton 1-22 MasterMill with a 40 Taper

JRock1000

Aluminum
Joined
Jan 3, 2018
Hi,
If this is the wrong subforum, please lemme know, or move this, or whatever is appropriate.
I recently moved in a Gorton 1-22 MasterMill.
It's got a NMTB 40 taper.
The Spindle bore is too small (about .6") to accept a 5/8" drawbar.
Not so much looking for solutions (although great ideas are always appreciated).
More looking for confirmation that this came from the factory like this? Or is this a retrofit?
How far out does your spindle nose stick from the quill?
How does the drawbar in your Gorton 1-22 Mastermill work?
Thanks!
P1080073.jpg
 
I cannot answer about how a 40 taper spindle works? My mastermill has a brown & Sharpe taper. My drawbar has an internal stop that when you loosen the drawer after about two turns it pushes the collet open and further turning removes the collet, no having to tap on the top of the drawbar like a bridgeport. Over the years I have been around a couple of other mastermills and they all had the same drawbars and b&s collets. Your 40 spindle is unusual? Its possible its factory or it could have been modified? Certainly easier to find 40 tooling than b&s these days?
 
Thanks so much for your reply.
So your drawbar doesn't pull out from the top?
It shoulders up on the bottom of the spindle, so when you turn it, your toolholder is ejected?
I think I'm starting to get it.
That's brilliant.
I guess I might as well go with CAT 40 (minus the pullstud) and just leave it in there.
 
No, my drawbar will not come out the top. I have never had the need to take it apart. The mill came with a square wrench that fits the drawbar and about a half dozen collets. I have all my boring heads, drill chucks, etc, set up with 3/4" straight shanks, so I just leave the 3/4" collet in the spindle and just use it for holes. Most of my metal removal milling jobs I do on my kearney trecker.
 
I had a 1969 model 1-22 Mastermill with a #30 NMTB spindle in it so I know they offered more than #9 BS spindles. That one came with a Gorton collet chuck that took the ZZ collets up to 1", sort of like a quick change set up. I don't have a scanner but will mention this anyway, had some sales literature from Gorton at one time that explained some of the options available from the factory along with how they were built. It was pretty impressive reading it and even though I like the machines I now have I still wish I had that machine at times.
Dan
 
Thanks so much for your reply.
So your drawbar doesn't pull out from the top?
It shoulders up on the bottom of the spindle, so when you turn it, your toolholder is ejected?
Well, kinda. There's an extra piece. The drawbar will pull out the top like a Bridgeport but ...

The drawbar works the same as a Bridgeport except there's a collar around it about an inch or two from the top end. Drawbar drops down the spindle then the retainer piece screws into the top which captures that collar. Not tightly, there's clearance so when you unscrew the drawbar from the tool holder, it pushes the bar up against the top piece. Then further turning of the drawbar forces the toolholder out the bottom instead of the bar out the top.

Woulda been easier to draw that on a napkin :) I bet someone has the parts manual, it shows everything clearly.

#9 Browne & Sharp is the common taper. I've heard of nmtb 30 but never 40. Doesn't mean it didn't happen tho, Gorton would do just about anything people wanted. You could pop out the retainer piece from the top (may be it's left hand thread ? I can't remember) and make a special drawbar ...
 
Thanks for the reply!
That's great to know.
The drawbar that mine came with was some chewed up piece of all-thread, with a nut welded on top.
I had to cut it to take it apart and see what was going on.
Now I see why they did it like that.
Just wasn't sure if something was not right, or that was a simple (although slightly inelegant) solution to the fixed drawbar.
40 NS Spindle Nose was one of the options that came with it.
I think it has approximately the same cutting spindle as all the other options, just the 40 taper hangs out a little further.
The OD is threaded, so I'm guessing there was a spindle protector collar / nut?
Servicar rider - That's smart. I have an r8 boring head, and I've been wondering if I can't just put it in a 31/32" collet (or some other sort of adapter).
 
Parts manual is here : http://manuals.chudov.com/Gorton-MasterMill/Gorton-MasterMill-Maintenance-Manual.pdf
The different taper options are down on page 66 (and standard BS9 is 62).
All the diagrams are there, I just can't get a clear picture from them.
It seems like the drawbar should drop right in.
The original drawbar has that drawbar thrust nut at the top.
None of this is really a huge issue, I can work around it.
It didn't come with the original drawbar anyway.
It's just part of my consideration for the CAT 40 / NMTB 40 - Shoulder / No Shoulder thing ;)
I want to be able to take the best (most affordable) of both!
 
Hahaha, So it turns out all my agonizing about the drawbar has gone to waste. The Ceiling is too low even if I could pull the drawbar out of the top! :D
Got the VFD hooked up (the spindle sounds good!), Now I'm going through and fixing the feeds.

Liljoebrshooter1 : I found your post on Home Machinist (I think) about setting up the VFD. Great thread.
I believe mine is a little older. It's an AC Dynadrive motor, and the Quill feed is geared and Belt driven.
I got it running when I figured out some of the treadmills I had cannibalized had the right length belt, I just sliced it in half lengthwise.
Sounds like some of the gears are a little loose, but I can deal with that when I get there.
The Circuit to run the clutch for the DynaDrive is a Tube circuit!
The motor is running inside of it, but the transformer is not hooked up properly to output the 120V-150V it wants to see. I'll spend this evening figuring out the wiring. I found an older maintenance manual, which has more pertinent info to my vintage, but it doesn't have the nice circuit diagrams like the more recent one. http://vintagemachinery.org/pubs/2136/20043.pdf
Another problem is the voltage is too low to activate the contactor switch, so I have to manually push the armature in to get the spindle turning...
Oh well, at least it works with a little workaround. The important stuff is sound, I just have to fine tune the peripherals.
I'll try to get some photos up tonight.
 
Does Anybody have a MasterMil form 58 or before? With the Tube Circuit and the Clutched AC Motor DynaDrive?
The Conduit box cover on mine has the diagram, but it's all corrodedby grease and gunk. When I wipe it off, the diagram comes off too.
I could follow the drawing, but I can't find one online (or even a schematic).
All the schematics I can find are for the post 58 DC Motor DynaDrive models (I believe they have solid state circuits).
 
Hi all,
i have a Gorton Mastermill Series I 22, not variable speed nor horizontal attachment. I bought it some time ago, and just hooked it up to power via VFD. My question is about lubrication for spindle head/bearings. Only info I can find find in manual says to shoot three shots of grease into a zero. On the power downed control box on left side of mill, says fill w/# 30 machine oil.
I know its a dumb question, but don't want to burn up spindle for lack of lube, have no idea how ell or when spindle was gone through. Sounded good when testing it for short period, no chips yet.
Any help appreciated.
Thanks
 
Congratulations.
That's what the manual says, grease in the zerk, turn everyday.
I filled the Gearbox up, but over time, it's wept out (it's a mess), but it works well.
Need to refill sooner than later, and while I'm at it, tighten everything up, so maybe it doesn't leak out.
Mine screams a little at higher RPM (actually as you move the belt higher on the pulley stack), but it runs great.
If your spindle sounds fine, you should be good. Commence to cutting :)
 
Does anybody have a picture of the draw bar retaining collar setup? My 1959 Mastermil has an R8 spindle, but no retaining collar. I would like to set one up.
 








 
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