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Lucas 542b-120 questions


Nov 9, 2022
so I'm pretty green. First post etc. Only been machining a couple years and only cause the last guy at my old job quit. So if this is in the wrong place please direct me where it should go.

That being said, I moved to a new shop and am now occasionally running a lucas 542B-120. I'm in a little over my head.. the machine needs a fair amount of service as far as I can tell. Mainly seems like the pendant controls. The neut-low-med-hi speed selector works almost at random. Can try 30 times to put it on neut and won't go. Then suddenly, vigorously turning the switch a big psssshhh and it'll change. So I'm thinking there's pneumatic controls to the pendant.. there's other issues too but I think a lot of them are related to this same thing.

I haven't started opening things yet. One, because I'm pretty new there and two cause I don't want to cause even more chaos and make it worse..

Can anyone give me the nickel explanation of how this whole system operates? Or even schematics showing how the controls work?

Thanks from nothing

Having a similar problem with a 441b lucas. Tries but doesn't shift ranges sometime. Older machine and no one else in the shop knows or wants to use it.
New problem cropped up this week that may be related to the range shift. I was trying to change feed rate. The levers move but don't change the rate.

Does yours have the power tool clamp? (#50 taper) Got issues with this too. Some times I have to use a pry bar to assist the ejection.

Interested in any responses to this.
Should have brought the books home to read up.

Yeah similar problems. Clamp works great. Does not feed but reverses like a champ.. so useful. Have to feed the spindle to use it.. or crank it by hand which is no small feat... Oh and then dodge the handle I forgot in it when I go to reverse it... My coworker is content to just use the spindle and call it a day. Seems like a lot of fancy stuff being wasted
These problems are way out in my ballpark's left field, but quite a few years ago I stumbled over Lucas Precision's website when looking for "independent verification" of a machine-leveling process. I found whay I was looking for, and a trove of documents describing methods od instsllation, maintenance, and repair of Lucas HBMs.

The Lucas Precision website was revamped several years ago, and some of the older documents disappeared, but I'd still recommend STRONGLY that owners and users of Lucas download and save what's still available


Edited to add:

The location of the downloadable documents is well hidden. Start at Service and Spare Parts, then Level and Alignment, and then click on the red bar, white lettered Online Technical Assistance.
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I love a Lucas. They are complex however. I've been deep inside many sections of mine.

If you're having trouble with feed, check to see that your clutch (rapid and feed) brushes are in good condition. If so, check to see that they are receiving 24vdc when the feed or rapid are engaged.

The pendant controls can be tough to diagnose and I've installed my own new switches to override whatever is in there to keep the machine from running when something in there is telling it not to.

Never let your head clamp run dry of oil or you're going to have the fun task of bleeding it. If anyone has a trick to doing this process easily, I'd love to hear it.

Lucas has been very helpful throughout the years and they have a man who will put together any of the original spiciness they have for your machine. You have to pay for this service but it's a reasonable cost.
Regarding electromagnetic wet clutches, Lucas turned me on to this company: https://maps.app.goo.gl/NuMboA2a3QrnWruu7

They are fantastic, fast for what they do, and close enough to being so cheap you feel like you're taking advantage of then.

The owner Bruce will talk with anyone who calls.

They built me two custom clutches last year and they were expertly built.
Our shop had a couple of Lucas boring mills. One was pneumatic, I feel your pain. I only used it if the manual one was tied up or if someone else had it setup and I had to follow. I would guess dirt and moisture has caused the problem with yours. I never had to work on the mill itself, just machined on it.
Place I worked had one similar to that. I never did any service on it, but I know they had issues with the pneumatics one time. It turned out it was not getting enough volume of air. A pressure gage at the machine read correct pressure so they did not suspect that as a problem. Turned out the air lines in the building going to it were partially blocked up so when the machine needed air the pressure would drop off for an instant causing things to not work correctly. They added a reservoir at the machine and that solved the problem.
Hey thank you all for your help! I did some further rooting around at their website and found they do pendant upgrades now bc the special switches haven't been manufactured from a while.. following on that l found a thread back here that I had missed relating directly to the switches. Like stacked multi cam switches that controls relay ladder logic. At least I have a better understanding of how this all works.
I'm semi-retired and work here 2 days a week, still enjoy it.
This is way out of my experience digging into the controls. I has a cpu in it I recogize from about 25 years ago from my previous job. Doesn't look original to me.
Trouble is we don't have enough work for it right now. I'm hoping the boss will justify getting an expert in to set it up right. I will pass on the above info.
I don't know how long it sat before moving in.
The switches on the pendant seem a little wonky at times.

Thanks Dave