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The Design Shop / Re: Surface grinder concept/project
« Last post by JHovel on Today at 08:09:47 AM »
CC Engineering Industries Limited, Sydney Australia
I was given it in a very dilapidated and worn state and restored it including re-scraping every single sliding and flat surface on it. Lovely little tool in use now. Here is a link to one on the original cast iron base recently sold at auction: https://www.grays.com/lot/0006-5048538/mechanical-workshops/cc-engineering-industries-surface-grinding-machine
They made several T&C grinders, arbor presses and assembled other tools like chainsaws that were highly import taxed, from parts supplied by others, fabricating or casting the required local content to permit a "Made in Australia" label to accommodate the laws of the day. This was true for many imported goods, like almost all automobiles and trucks/lorries, until the mid-'80s. So our "local" car manufacturers were GM, Ford, Volkswagen, Citroen, Toyota, Leyland, and many others. The labour content of those was sufficient to be local goods. They even assembled Rolls Royce cars here.
There is a story of a wealthy farmer in the 50s writing to Rolls Royce asking to made a more suitable car for Australia, with wide running boards, since the current models of the had nowhere to put dead sheep found in the daily use of the car on the farm....
Many other companies had assembly plants here like Bosch, Hoover, Metabo.  They are all gone now since the repealing of import duties. No tools or cars or electrical goods made in Australia any more.... except very specialised stuff like mining machines, trains etc, mostly with imported parts, because all of the feeder industries for those parts are gone too now, of course.
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Project Logs / Re: 3d printer - Leapfrog creatr conversion - a new can of worms
« Last post by BillTodd on December 04, 2023, 01:46:34 PM »
A sleek Biqu microprobe arrived promising +/- 3um accuracy ....



While measuring the logic output, I found it  has a linear range of about 200um thus making it entirely reliant on the logic threshold of the I/O port -   :bugeye:

I cannot seem to get Marlin to use the probe as a Homing device , which is what i bought it for , as i don't really need to level the bed every print and only want to be able to change surfaces (which will vary in height) .


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Metal Stuff / Re: I bought another deader
« Last post by ddmckee54 on December 04, 2023, 12:59:45 PM »
Good luck Tom, let us know how it goes.

I finally got around to cracking the top half of this thing open last weekend, and the coil is definitely dead.  I don't know if I'm going to be able to save the ceramic furnace liner / coil winding guide or not.  I'd like to save it as the ceramic liner seems to be in good condition.  After they wound the heating element on it they smeared some type of goop over the coil on the outside of the liner.  It MIGHT have been a refractory compound of some type, but as cheap as these things are, I doubt it was a proper refractory.  It's cracked pretty badly so I doubt it was rated for the temperatures it actually saw.  It's probably just plaster and sand, but since it's been smeared over the heating element the coil is acting like rebar.  I'm going to try chipping that crap off the liner, but I'll probably just have to get a new liner - they are less than $50.

Or I may just get some decent castable refractory and make my own liner, the size I actually want it.  I've got to make a new top and bottom for the oven anyway.  This is going to be a burnout oven, not a foundry furnace so it won't be seeing metal melting temps.  I've got 3D printers, I can easily print the molds to make a liner.

Don
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Project Logs / Re: Building Wildings Tower Clock
« Last post by raynerd on December 03, 2023, 07:28:39 PM »
Thank you so much for the pictures! Really helpful.

Another question for you. Is the lantern pinion on the 2nd wheel arbor fixed on with loctite. I presume so as I canít see how else itís attached and Iíve read the book countless times. Iím certain it must say it somewhere but Iím missing it!
Chris
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Electronics & IC Programing / Re: Simple way(s) to run a bipolar stepper motor?
« Last post by Muzzerboy on December 02, 2023, 03:29:56 PM »
You have to realise that stepper motors need to be current driven, rather than voltage driven. Most drivers regulate or limit the current once it has reached the level needed to index the motor to its next position. If they didn't do that, there is nothing to limit the winding current in the motor. If you had a 30V power supply and a 3 ohm motor, you would end up with a steady state current of 10A (for a fairly short time!). Instead, they typically use a full bridge with PWM modulation to limit the current and hold it at a sensible (programmable) level.

When you control the position with multiple microsteps, you come closer to driving the windings with 2 sinusoidal currents that are 90 degrees out of phase. However as noted, these need to be currents, not voltages and they need to be a sinusoidal function of the rotor position, not uncontrolled.

As the motor speed rises, you need more voltage to overcome the inductance. Or if you like, the motor develops a back emf (voltage) that is proportional to speed - and when that back emf reaches the power supply voltage, you can't drive any current into the windings. As torque is proportional to current, that means your torque has fallen to zero. This is something that often gets overlooked when people focus on the headline (stall) torque, not appreciating that the torque will fall to zero with speed.

That opamp circuit with the MOSFETs is a (linear) voltage driver, so not really suitable. Ideally it would be a current source, either PWM or linear.

Take the time to study a modern microstepping driver IC, like the I've linked to here. You may not want to take the easy route out but if you digest the datasheet and application notes, you will gain a better understanding of what is needed to successfully drive a stepper motor.
https://www.allegromicro.com/-/media/files/datasheets/a4988-datasheet.pdf
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Electronics & IC Programing / Re: Simple way(s) to run a bipolar stepper motor?
« Last post by sorveltaja on December 02, 2023, 03:14:22 PM »
Old post but to run a simple stepper motor as a regular small speed motor, an AC supply of 24V and 2 none polarized 4,7 uF capacitors in parallel will drive the motor like a single phase motor at mains frequency. Capacitors may vary depending on the motor

I've seen some Youtube videos of how to do that, and from what I understand, it's rather limited way. Also, I doubt if there is any useable torque available.

I haven't watched all videos of the subject, but generally they just seem to show, that it's possible to make a stepper motor rotate using that method. But how does it handle even modest load?

As Joe mentioned, there just has to be certain signal for both coils(when talking about bipolar stepper) in certain order.  I guess, that's what makes it possible to produce torque.

--
I know it's been a while since I last posted. I really would like to get back to this project, but meh, there are other things that keep me occupied. It just sucks when that happens.
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Another of the castings sets I bought back in the day but never got around to.

This one is the Les Chenery Gypsy 1 Engine Castings + Drawings Kit mentioned in the title. It is available on eBay, to UK buyers only, as eBay item number 256319671038, link : https://www.ebay.co.uk/itm/256319671038  Initial bid is set at £255 with no reserve.  At the time of posting this there are 5 days to run, end date is Thursday 7th Dec at 19:30 GMT.

The castings are entirely unmolested and in the same condition as when I received them from Les Chenery before he passed. I believe the castings and drawings set to be complete, but what is pictured is what is supplied, nothing else is available.

Auction blurb as follows and pix below:

Quote
Les Chenery 1/4 Scale Gypsy 1 Engine Castings Kit + Drawings. In New, Unmachined Condition

You are looking at a Castings Kit and Drawings Set for a Les Chenery designed 1/4 Scale Gypsy 1 Engine in new totally unmolested condition.

Note that although a picture is provided of a completed engine for the information of the viewer this auction is solely for the castings and drawings kit as described below. An external youtube video, reference YL8HKUpodls "1/4 SCALE INLINE 4 CYL 62cc De HAVILAND GYPSY MK1 AERO ENGINE MAYFLY OLD WARDEN SHUTTLEWORTH - 2016" of another completed engine in running order is also available to interested bidders. NEITHER OF THESE COMPLETED ENGINES IS SUPPLIED AS PART OF THIS AUCTION.

These were provided to me directly by Les Chenery before he passed and the following will be supplied as pictured :

1 off Upper Crankcase Casting
1 off Lower Crankcase Casting
1 off Rear Cover Casting
4 off Engine Mount Castings
4 off Rocker Mount Castings
1 off Small Front Cover Casting
1 off Carburettor Casting
1 off Crankshaft Bearing Cap Casting

9 off A1  sized sheets of drawings comprising 8 off detailed drawings and 1 off general arrangement drawing.

The prospective bidder shuld be aware that nothing not pictured will be supplied, only the 14 off castings and 9 off drawings shown will be supplied as part of this auction, this is the full set provided to me by Les Chenery.


Prospective bidders will hardly need to be told that these castings are no longer available and are as rare as hens teeth.  You are pretty unlikely to find a set from another source any time soon so please consider that in your bidding.


The drawings I have are rolled and I can obviously supply them either rolled or folded as the buyer prefers.  The quoted price for shipping includes shipping the plans as a separate item in rolled condition. I will apply a discount of £7.00 to the total cost if the buyer would prefer to have me fold the plans instead since this means they can be shipped in the same box as the castings. If folded plans are your preference then message me via eBay after the auction ends and I will apply the shipping discount.

Thanks for your interest,

Boo




















































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Member Videos / Re: Lever Locking Topslide
« Last post by jackary on December 02, 2023, 10:12:59 AM »
Here is an underside view of  the lower slide
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The Design Shop / Re: Surface grinder concept/project
« Last post by BillTodd on December 02, 2023, 09:49:40 AM »
Hi Joe,

Nice little grinder. What make is it?
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The Design Shop / Re: Surface grinder concept/project
« Last post by JHovel on December 02, 2023, 07:22:26 AM »
I have a small CC tool and cutter grinder that I uses as a surface grinder.
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