MadModder
Gallery, Projects and General => Member Videos => Topic started by: RotarySMP on February 28, 2021, 08:17:25 AM
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I couldn't resist when this came up for auction..
There is not much online about such old CNC electronics, so I decided to a video as a tribute to the electronics and computor engineers of the 1970's. While it would be cool to get it going as is, without any manuals or knowledge of the schaublin interface with the Data General Nova, that is not feasible. I will remove the controller as a complete module and send it to a museum or collector. It wont get scrapped.
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Fascinating stuff! Yours was machine #12 in 1981 judging by the label. The date codes on those ICs slightly predate that, which makes sense.
Jealous as hell, will be watching!
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Oh yeah, thanks for pointing that out. knew there was a reason why I suspected it ws from 81, but lost track of why I thought that.
Mark
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Well, no turning bck now...
Mark
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Whatever cutting oil was used in this machine dried up like varnish. I am having to tear it down further than planned to clean this out, as the slides are stuck down.
Mark
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Did you find out how the belts were tensioned?
Loving the videos.
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There is nothing, so the belt tension is what it is. I also find that weird. There are no taper pins, so a tiny bit of slop in the screw holes can be used.
Mark
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I pulled the Saddle off this week...
Mark
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Made a little more progress, but also a bit of a set back:
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I procrastinated as long as possible, but it is time to play workshop tetris.
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Looks like there's very little grease in those bearings, but then again most people tend to over-grease them. When I put new spindle bearings into my Hardinge lathe I looked up the manufacturer's spec for the amount of grease to use and I was surprised at the small amount required - 4.6cc
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Thanks for that. I knew it was only a small amout, like 15 or 25%, butit is nice to see the table with the amount in g. I'll use that.
Mark
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I assume you haven't got access to the inner race of the front bearing behind the labyrinth seal. To remove front bearing would mean putting pressure on the outer race to drive off the inner race which isn't recommended bearing practice. If the bearing is very tight on the spindle you might exceed the axial loading limit and damage the bearing. If the bearings feel very smooth I'd go for injecting a small amount of grease.
Having said that the lower bearings on my mill are much smaller a/c bearings and a stuck 2 morse taper attachment takes a sharp knock on the end of the drawbar to release and 30 years of sharp knocks doesn't seem to have done the bearings much harm. (And they've never been regreased.)
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Yeah, the only way to put force on the inner race of the front pair is through the labrynth seal, which is cast iron. I have nightmares of it going Ping, as it must hae plent of non-radiused corners.
If the belt hadn't failed, I probably would have taken my chances with the 40 year old grease. Kluber is very good quality grease.
Mark
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I would not take that spindle apart !
I have replaced lathe spindle bearings on simpler lathe spindles - as you say - major pucker factor - even simple lathes have very expensive bearings !
I'd either lubricate in place or leave be.
The bearings and grease on my HLV-H are now 55 years old and still OK, I have the urge to pull them and lubricate too.
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Mark,
I definitely wouldn't take it apart, a long soak in solvent, I'd then try to "flush" it with diesel with your syringe before re-rinsing in solvent blow dry and grease!
"If it aint broke" ............................
Cheers, Matthew
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Thanks. Yep, that is what I did...
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So i saw!
Gave you a like!!
If by chance you find yourself in Paris, (Le Bourget air show?) look me up!
Cheers, Matthew
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Thanks. I went to the Paris air show once. Must have been about 1999 or so. Very cool.
Mark
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Tip for pulling reluctant dowlpins , use an er collet chuck to grab the pin and threaded rod as a diy slide hammer.
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And when you replace them always put one in with a female extractor thread - dead easy to do, and the next bloke to come along will thank you !
(Had that issue with the powered tooling gear boxes on my CNC lathe, making a female threaded dowel was the work of minutes on the lathe.)
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Good points. I'll check if these are hardened, and if not I could drill and tap the end.
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Little more progress...
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Good to see another instalment of this story.
Are you keeping the variable speed drive as-is? If so, how does the control set the speed?
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I'll keep the variator as is. I have the little control board to set the speed. However, I'll use a VFD as the main speed control, as it will replace a significant number of large control relays thus taking up less cabinet space and wiring. Basically I'll have the VFD, the Variator and the backgear. Total overkill, but easier just to leave that variator in than replace it with a drive belt. I am not sure how I will implement the control logic in LinuxCNC. The speed range between the VFD and the Variator totally overlap.
Mark
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Is the variator manually adjusted?
If so you could normally leave the variator in the upper end of its' range and use the VFD to get the spindle speed you want. Just don't run the motor rpms below 20%-25% of the full motor speed or you'll run into motor cooling issues. Below that speed the motor's fan won't be turning fast enough to move enough air to cool the motor.
The only time you'd need to adjust the variator would be if you needed a spindle speed that was above the back gear range, but that spindle speed put the motor speed below the 20-25% of full motor speed. If that happens, then crank the variator into the lower end of its' range. That would allow the VFD to bring the motor rpms up - hopefully high enough to cool the motor.
Of course this all assumes that you'll be running the motor long enough for the heat to build up enough to damage the windings. Or, that you'll be running the motor at this low speed for short periods, but with insufficient time between motor cycles for the heat to dissipate. In that case, the heat could again build up enough to damage the windings.
I installed an a 900HP compressor a few years ago that took over 25 seconds to come up to speed on start-up. It accumulated so much heat in the motor that we weren't allowed to try starting it more than 3 times in a 24 hour period - with at least 1 hour between each start-up attempt.
Don
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The way I think about it now (this might change) is that the work to hook up the variator is so limited, that I may as well.
Whether I just put a variator up and down button on the control panel and use them to manually bias the speed range like you discussed, or implement a more complex logic in LinuCNC and have it control the variator, VFD and backgear... I so far havent decided.
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Here we go again...
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Here is the latest...
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Here is a pneumatic follow up.
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I am waiting for pneumatic fittings, and so started the electrical cabinet.
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I know a lot of people swear by Plasma cutters. I just want to swear at it.
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This took a lot more work than expected...
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Looking excellent :thumbup:
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Thanks Andrew. At my pace still a lot to go, but that cabinet chop up was a milestone. From here it is mostly reassembly, wiring etc.
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Nice work
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Thanks. I look forward to adding bits back in, rather than removing them.
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I was planning an other victory in the continueing struggle of Man v Machine... but then...
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This week, I got the best of the machine.
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I would have expected Schaublin to make the piston alignment pins a closer tolerance.
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Next up... that drivetrain
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Didn't get a lot done over the holidays...
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THis time I did make decent progress on the electrics.
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A bit random this week, but I spent most of my free time learning QElectroTech. Great free software for doing industrial schematics. Still have a lot to learn.
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I forgot to post the last video. I think for the last five weeks, I started each week thinking... "this week I will get the spindle motor running"...
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Hi,
I'm sure (not exactly sure but would expect) that there will be connections for a braking resistor on your VFD.
My lathe is a similar size to yours and I can stop a 160mm chuck from 2,400 rpm in less than a second.
I have 2 off 220 Ohm 50W chassis mount resistors wired in parallel and fastened to a smallish finned heatsink. (Equivalent to 110 Ohm at 100W I hope.)
Cheers.
Phil.
P.S. Loving your videos.
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Thanks Phil, the Lenze brak module for this VFD is 300W, but since there is a mechanical brake mounted on the motor shaft already, I would rather just let the vfd coast down, and mechanically brake the load. Havent worked out whole to set that yet.
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I took a Uni course in machine tool design, and figured I'd try out what I learned on the Schaublin...
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I didnt post last weeks video to this thread, as it was more of an unsuccessful casting vid than a Schaublin progress report. This week is better.
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This week it is the X-Axis motor mount...
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I have never had a power chuck before...
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Bit of lathe work on the Boley required this week, but good progress...
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Some more minor steps...
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Oops, forgot to link in the last video...
It is looking more and more like a lathe...
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Bit random this week :)
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A step backwards this week.
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I made a nice step forward this time...
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I forgot to link last weeks video...
and this week I worked more on mechanical bits.
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Our #1 Nico shot down my first plan for this part...
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Oops, I forgot to link the last couple of episodes.
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I was wondering when we'd see some more episodes - thanks.
:clap: :clap:
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Hi Phil,
Sorry about that. I was back in NZ for a month, and also working on a few other projects.
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Hi Phil,
Sorry about that. I was back in NZ for a month, and also working on a few other projects.
Don't apologise!
I thought setting up Mach3 with stepper motors was complicated enough. You've put me off servos.
Cheers.
Phil.
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I am sorry to hear that. I think I am pretty lame at this stuff, and most people could do it much faster and more easily than I do it.
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Adding conversational programming is a real game changer for a home shop machine like this...
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Bugger!
Better luck with the next one.
You may have got away with it if you didn't keep taking a cut on the taper. A short parallel section wouldn't have done any harm.
When using the 4-jaw I find it easier to use 2 keys at once.
Phil.
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Thanks Phil. Good point.
It will be easier once I have the control panel set up and can more easily switch it out of back gear, but yeah, a second key would be quicker.
Cheers,
Mark.
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Hi Guys,
I forgot to link in the last few videos on the Schaublin retrofit...
sorry about that.
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Wow definitely holding out on us! That should keep us going for a while.
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Hi Tom,
Sorry about that. I have been a bit distracted, as I also made six videos on overhauling the DoAll gearbox in the last couple of months.
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No problem hell it’s been a long time since I posted anything but I do enjoy following along hopefully learning something.