New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

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MotoWerx
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New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by MotoWerx » Fri Mar 06, 2020 6:22 pm

None of the machines were powered when I got them, so I could not test them. In fact they had sat for more than 15+ years in his workshop. It was all more than I really wanted (I was only going to look at the lathe when I saw the mill in the corner and the drill next to it) but I wanted to help the widow out and bought it all from her at a good price letting her know I would be selling most of it as I didn't needed it all. Hindsight: While I made a pretty penny at the garage sale I had I should have kept a lot of the Mitutoyo measurement tools, granite block etc but I didn't think I need them and wanted to recoup some of my spent money. (The drill I really didn't need and it was sold)

Anyway, the gentleman had covered everything in cosmoline years ago so there was very little rust on anything but the dust layer was immense.

Fast forward 8 months and I finally get around to cleaning the mill up, pulled the bed off to clean the ways and lead screws. From my experienced "YouTube" knowledge, the ways look great with the original scaling (is that correct way to say that?) very much visible. I have it powered up on a 20hp American Rotary Phase converter and the motor runs great so far. Didn't really hear much noise in the head. (I did have to replace the fwd/rev switch as it broke)

Problem 1: the auto feed doesn't seem to work. When engaged the quill doesn't move down unless I put slight pressure on the the quill handle. Even then I feel what seems like a gear skipping in the handle. I have not taken the head apart yet to see if something is stripped or slipping but wanted more experienced wisdom before I do.

Problem 2: I just purchased an Edge Technology Pro Tram to tram the head and found something odd. While I was spinning the tool/spindle by hand, I noticed in certain positions of the spindle, the quill would bind as I tried to lower the indicators to the table. Strange, not sure why this would be only in certain positions. Is something bent causing the binding? I do have the original manual for the unit but this is basic at best with only exploded diagrams for parts.

So there it is, I am hoping someone here can give me a direction to go and help me out.

Oh, about me, I am not a machinist, I only like to play one as a hobby. ;)

I like to tinker around in the garage making, breaking, fixing, & creating things. Not sure where having these machines will lead but I like having them and hope to learn to use them successfully. (I did start out with a Jet Mill/Drill RF-18 and an old 80's Hales (knock off) 1236 lathe so know the basics)

thank you all in advance for any help you can send my way!
-Dave

I live my life in a confused haze only to be interrupted by moments of Brilliance!

~Dave (me)
2004

spro
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Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by spro » Fri Mar 06, 2020 9:27 pm

It is easy to say both issues are related. Auto feed can wipe a worm wheel in a jam. Further it could bend the shaft. I think you're going to have to get in there.

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mcostello
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Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by mcostello » Fri Mar 06, 2020 10:09 pm

I have a JTM 4 and have had the head apart. Mine has a bent quill skirt and I need another one made as theoretically no parts available. There is a clutch adjustment on Mine under the round cover on the left side of the head that has the lever going to the micrometer stop rod rod. There is an overload clutch in there. You might have something sheared in there.

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Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by Harold_V » Sat Mar 07, 2020 2:43 am

MotoWerx wrote:
Fri Mar 06, 2020 6:22 pm
the ways look great with the original scaling (is that correct way to say that?)
I suspect you're talking about the flaking, the pattern scraped in to the way surfaces for oil retention.
Some folks like to call it frosting, a term I don't much care for. Makes no sense.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

pete
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Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by pete » Sat Mar 07, 2020 5:29 am

Yep I think you mean flaking not scaling. It's used as a method to help retain oil on the way surfaces and prevent any wringing together of surface ground or even scraped parts. Depending on exactly how it's done and by who, in some cases it can look a bit like patterns of frost on a surface so that's where the frosting term comes from. Other methods of flaking looks nothing like frost. While there Youtube channel is mostly about repairs and rebuilding Bridgeport mills, these guys are the best and most knowledgeable for the smaller light weight vertical turret mills https://www.youtube.com/channel/UCiqCbE ... 34vkx7j-zg that I know of. All of the off shore clones were probably originally based off the mechanical design of the Bridgeport's so some of H&W's past videos might be of help with your issues.

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MotoWerx
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Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by MotoWerx » Sat Mar 07, 2020 9:42 am

spro wrote:
Fri Mar 06, 2020 9:27 pm
It is easy to say both issues are related. Auto feed can wipe a worm wheel in a jam. Further it could bend the shaft. I think you're going to have to get in there.
Ya, I think I am going to have to pull it a apart. Was playing with it last night and its only at the top of the quill stroke but something is rubbing the quill as it goes down. It stops after about 2"'s or travel and is smooth the rest of the way down.
mcostello wrote:
Fri Mar 06, 2020 10:09 pm
I have a JTM 4 and have had the head apart. Mine has a bent quill skirt and I need another one made as theoretically no parts available. There is a clutch adjustment on Mine under the round cover on the left side of the head that has the lever going to the micrometer stop rod rod. There is an overload clutch in there. You might have something sheared in there.
I have been looking at the JTM4 for finding parts - some still available out there. Was thinking it might be clutch related as well.
Harold_V wrote:
Sat Mar 07, 2020 2:43 am
I suspect you're talking about the flaking, the pattern scraped in to the way surfaces for oil retention.
Some folks like to call it frosting, a term I don't much care for. Makes no sense.
That's it, flaking. :oops: thank you for the correction.
pete wrote:
Sat Mar 07, 2020 5:29 am
While there Youtube channel is mostly about repairs and rebuilding Bridgeport mills, these guys are the best and most knowledgeable for the smaller light weight vertical turret mills https://www.youtube.com/channel/UCiqCbE ... 34vkx7j-zg that I know of. All of the off shore clones were probably originally based off the mechanical design of the Bridgeport's so some of H&W's past videos might be of help with your issues.
Have watched their whole series on the Bridgeport. Exactly as you have said, my import is basically the same design. I will watch the head disassembly one again before I dig in.

Thanks all for the help. I will be sure to report back when I find the issue.
-Dave

I live my life in a confused haze only to be interrupted by moments of Brilliance!

~Dave (me)
2004

Harold_V
Posts: 18314
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: New Guy with a problem(s) - 1989 Jet JTM-1 Mill with posible bent Quill or Spindle?

Post by Harold_V » Sat Mar 07, 2020 5:17 pm

MotoWerx wrote:
Sat Mar 07, 2020 9:42 am
spro wrote:
Fri Mar 06, 2020 9:27 pm
It is easy to say both issues are related. Auto feed can wipe a worm wheel in a jam. Further it could bend the shaft. I think you're going to have to get in there.
Ya, I think I am going to have to pull it a apart. Was playing with it last night and its only at the top of the quill stroke but something is rubbing the quill as it goes down. It stops after about 2"'s or travel and is smooth the rest of the way down.
Keep in mind, I am not familiar with the Jet, but I own a BP, and I suspect they are built similarly. Might not hurt to check this, and it's done easily.

On the back side of the quill (the outer portion of the spindle) there's a series of teeth which are used to move the quill up and down. It may be that there's some crud in the teeth. I'd suggest you extend the quill completely, then examine the teeth for any issues. While the quill is extended, wipe it down well and apply fresh oil. There should be no discoloration (black substance) on the quill. If there is, keep wiping and oiling until it is gone.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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