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Been trying to resolve the 'Turret Unclamped' switch issue where it seems very slow to operate when cold taking up to 10 seconds for the contact to close when the Turret it pushed forwards for a tool change by the hydraulics.

It is a Euchner EGT1/4A5000 'precision mechanical switch' rather than a micro switch or proximity switch as one might have expected. It's end is a ball  that bears on the turret shaft that has a suitable ramp shape so the the switch is made in the unclamped forwards position, and open in the clamped reverse position. I had already removed it, lightly lubricated it's shaft and replaced it, but the symptoms persisted. Putting my meter across it and hand operating to be frank there wasn't any stickiness apparent, so maybe it was just mal-adjusted.

The construction is awkward in that the adjustment collar and locking nut are not 'get at able' when the flange mounting is installed, so any adjustment has to be a long drawn out iterative affair, making a little tweak, re-installing, trying and then removing again for another tweak. The movement from open to closed is microscopic, so that the adjustment took many iterations  :bang:

I have tracked down a very expensive replacement but hopefully today's tweaking session will have resolved the issue. Interestingly it's locking ring was by no means tight when I first removed it.

Electronics & IC Programing / Re: motor brushes
« Last post by Doc on Today at 08:55:48 AM »
One other thing that could happen is the insulator material between the com. plates should be below if they are flush or slightly above they can cause the brushes to arc and fail after just a short time.
Electronics & IC Programing / Re: motor brushes
« Last post by picclock on Today at 04:43:30 AM »
It may be that the armature has a fault, such that when the brushes contact a faulty shorted winding the excess current flow causes the brushes to heat and disintegrate.
I have used carbon rods from a U2 battery to make temporary brushes for a hoover, and they lasted quite a few months before I got around to replacing them with the proper spares. So even the wrong carbon should last a reasonable time.

Best Regards

How do I?? / GCS900-2D DRO change mode ?
« Last post by picclock on Today at 03:36:40 AM »
I cannot seem to change mode from a MILL-3 to a LATHE-2. It might have helped if I had the manual, though not necessarily so.
This is a cheapo DRO which I ordered with 1u resolution on AlieExpress. When it came 5u was supplied. I think they sent the wrong scales. Went to dispute and I got ~ 30% off. This all happened some time ago.

However I figure I can use it on my lathe, but its set to MILL-3 and I can find no way of changing it. I can get into the setup routine and change the axis resolution and other params (by holding the '.' button on power up) but it does not give the option to change the mode. The manual has disappeared into the nearest black hole, doubtless it will turn up when I no longer need it.

An earlier version had an s key on the left hand side of the display, but although the panel has the 's' key marked there is no button.

Any assistance greatly appreciated.

Best Regards

New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on November 18, 2018, 03:16:28 PM »
I've been put in touch with a couple of firms who may be able to to make a bronze cast from the STL model via the Home Workshop advert.

As an aside I was amused to find when fiddling with the PLA print and the original Beaver drive dog that they tessellate. All Beaver have done is to put a drive dog on the drive shaft that is identical to the Baruffaldi one on the powered tools and presumably make powered tools with fittings like the one I've made. i.e. they swapped which shape was on which !

I've just printed an ABS one that seems quite strong

New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by mattinker on November 18, 2018, 03:10:00 PM »
I printed the second (Mk2) version earlier but not had time to try it yet, but also I've put an advert on the Home Workshop site asking for contacts who can cast bronze from an STL model - you never know! OK it's a bit of a cop out, but having lost wax cast myself years back I know the myriad of special bits and pieces you need to scrape together to do it. Also the special plasster has a short shelf life and only comes in big bags !

It's not a cop out! To make a sand casting, it will need to be divided in two and given draft. This should be easy to do ! I attached a drwing in .png format, I can't see it in the preview.

Regards, Matthew
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by tom osselton on November 18, 2018, 02:41:45 PM »
Or try this
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by nrml on November 18, 2018, 02:22:20 PM »
On mulling over this a bit further, is there any reason why printing this with ABS and treating it like a wax model for casting in bronze but using an excess of acetone to dissolve away the core instead of heat wouldn't work?
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by philf on November 18, 2018, 02:18:58 PM »
Is there enough meat in the teeth to drill holes for steel dowels for reinforcement? (And perhaps a steel sleeve over the OD below the teeth.)
Model Engineering / Re: A little light reading
« Last post by millwright on November 18, 2018, 02:13:04 PM »
Great Tom, thanks for passing that on, just had a browse the a few issues. I never tire of reading the old ones. my own collection starts in 1950 so I have plenty of reading to get up to where mine start. :thumbup: :clap:

regards John
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