Tom Senior Vertical Mill Y axis stuck

[tgglassParticipant @tgglass]

Hi all, hope all is well.

Don’t much in the ways of an engineering / machine wizardry background as I’m a scientific glassblower so I’m hoping you chaps can help us with an issue we’re having in our workshop.

We have a Tom Senior Vertical Mill (?) which we use to mill out grooves in glass flanges, however getting it to move along the Y axis is nigh impossible, used to always be fairly stiff but of late it’s absolutely immoveable, needing us to have 2-3 people trying to get it to move up and down for what feels like an hour to get it to move about a mm of movement, but we feel like it needing that much force is definitely a sign of something being wrong and we’re afraid of breaking something. We’ve tried cleaning it up and lubing everything up as much as you physically can but nothing seems to help. We asked a guy who used to do engineering for us how to fix it and his suggestion was to just lube it up but obviously that’s not working.

If relevant it comes into contact with diluted hexol (contains ethanolamine) to reduce the friction and the glass dust (again I’m not an expert) but this stuff gets absolutely everywhere so it might have caused things to rust I think?

Any advice or tips are greatly appreciated.

TLDR movement on the Y axis on a Tom senior milling machine is pretty much completely stuck.

[Michael GilliganParticipant @michaelgilligan61133]

Sounds like there is a serious need for dismantling, inspection, and thorough cleaning.

MichaelG.

[DC31kParticipant @dc31k]

Please could you clarify what you mean by the Y-axis. You talk of moving it “up and down”.

In conventional milling machine terminology, X goes left-right, Y goes in-out and Z goes up-down.

It is important that we all use the same terms or you may receive incorrect advice.

[tgglassParticipant @tgglass]

Ah then I mean the Z axis sorry.

Thought it was the Y from graphs in school.

[Simon Williams 3Participant @simonwilliams3]

I suggest you check the slide way lock (little lever LHS of the knee) to make sure it’s released.  I think there is a short brass push stub down the threaded hole – has this jammed up?  If so you’re into keyhole surgery to invent a means to pull on the stub.

On a machine that isn’t exercised much the old rancid oil turns to varnish and acts as glue rather than lubricant.  Having abrasive in the mix makes this worse.  Loosen the gibs and flush out the goo with brake cleaner and new oil.  Don’t use motor oil, it will have detergents in it which love water (condensation) and make a nasty sticky emulsion.  Hydraulic oil thinned with paraffin or white spirit is a good maintenance cheat.  Automatic transmission fluid thinned with acetone is ideal.

Heat is your friend.  I suggest an electric fan heater blowing on the knee for a day or so the get the casting good and warm to release the sticky varnish.

The Z axis hand wheel runs in a casting below the knee, and turns pair of bevel gears and a threaded leadscrew in a bronze nut captive in the bottom drip pan of the machine.  If the hand wheel is stuck completely as you describe the stuck components are in the handwheel and spindle, not the slideways.  Which would be pretty odd as the relevant parts are sheltered below the knee.   If you’ve got a bit of backlash of the leadscrew turning against its captive nut then the jam is in the lead screw or the slideways – much more likely as the dovetail slide of the Z axis on the front of the column is exposed to the elements.

But the first thing to try would be to dribble some thin (thinned) oil down the vertical dovetails for a few days and see if things free up.  Don’t use WD40 – though it is good at getting into cracks and freeing things up it dries eventually to a hard varnish and then you have the same problem again but worse.

Do keep us posted.

Simon

[Neil WyattModerator @neilwyatt]

Is it one of these?

I’d start by loosening the gibs for the vertical axis off and seeing if once they come loose, movement is ‘free’, albeit sloppy.

If this happens then the drive is OK, if the drive mechanism is still stiff you’ll have to do a strip down to find the issue.

 

Well worth doing, they are lovely machines.

Neil

[mark smith 20Participant @marksmith20]

Im a chemist and know ethanolamine will attack copper ,brass and probably bronze ,so possibly youve destroyed the leadscrew nut.

[old martParticipant @oldmart]

https://www.denfordata.com/bb/viewtopic.php?f=15&t=2070&hilit=senior+manualThe adjustment of the gibs on a T S Z axis is a strange twofold affair. There are two sets of screws/bolts at right angles to one another. You could try loosening both sets to get the knee working for a start. The handwheel runs through a bevel geared right angle to turn the ACME lifting screw and the nut which takes the weight is at the bottom sticking out of the machine base. They are unlikely to seize up, but would benifit from a squirt of oil.

I can’t remember exactly how the gibs are adjusted, they are on the left side of the knee, without getting a look at the one we have at the museum. I think the screws with nuts are backed off a turn or two and the other bolts are slackened off and the block they hold is pushed to the right and held as they are retightened. The weight of the knee is supported by a helper and a cut length of 2×2 wood at the front, about 15 inches long. The screws with locknuts are used to fine adjust the gibs.

Getting somewhat off the subject, the Denford Forum PDF shows both the standard MT2 head and the extremely rare R8 head. Our mill at the museum has been converted to R8 to share the tooling that the other mill uses.

[mark smith 20]

On mark smith 20 Said:

Im a chemist and know ethanolamine will attack copper ,brass and probably bronze ,so possibly youve destroyed the leadscrew nut.

Sounds horribly likely.   I see Hexol is an industrial grade surfactant, so we have a powerful oil/grease remover that corrodes Copper alloys, mixed with powered glass.  Potentially nasty if it gets inside the gibs, leadscrew and nut.  I agree with Michael – strip and inspect.  With luck, the mill is just caked solid with glass powder, but there may be corrosion and erosion damage to fix as well.

The usual treatments for freeing up gummed up oil and dirt won’t work on glass.  It will have to be cleaned physically.

By the way, never force stuck hand-wheels!  Easy to damage the machine more seriously.

Dave

[BazyleParticipant @bazyle]

You haven’t given an indication of where you are. Perhaps there is a Model Engineering Society in the area that an lend a hand. You local school of tech college might not be doing any relevant classes anymore but may still have a teacher who knows more than just how to turn on a computer.

[old martParticipant @oldmart]

I have had second thoughts on how the knee gibs are adjusted.

Slacken off the front facing bolts one at a time and tighten finger tight.

Slacken fully the locking lever screw.

Hold the adjuster screws while slackening the lock nuts and then slacken the screws 1/2 turn.

The knee should be free to move up and down.

Screw in the adjuster screws until they just touch, starting from the central ones and working outwards and check for the gib just starting to hold the knee from moving easily. Tighten each locknut in turn while holding its adjuster screw.

Finally tighten the bolts and check that the knee can be moved reasonally easily with the wheel.

If I were going to do this, I would first remove the bed and Y axis, the knee, their leadscrews and nuts plus the bevel gearing for the knee and throughly wash and relubricate every part. And make sure the rubber guard at the back of the bed was in good order. The gib on the X is a taper gib.

 

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