Member postings for Clive Steer

Here is a list of all the postings Clive Steer has made in our forums. Click on a thread name to jump to the thread.

Thread: Multiple Bearings in Spindle
25/07/2023 10:22:55

Steve

It is common for ultra accurate spindles to have a separate bearing(s) for the drive pulley to take belt side loads and an axial spline or pin coupling to the spindle. This is the arrangement of the Hardinge lathe and my Bridgeport M milling head. On the Hardinge this done so that no belt/pulley rumble gets transmitted to the spindle allowing super surface finishes to be obtained.

Given the size of the cutters you are likely to be using most of the power will be needed to drive viscous friction loads of the bearing lubrication. The are some excellent brushless DC motors cheaply available that could be mounted axially provided you have the space.

CS

25/07/2023 10:01:04

I recently have replaced the spindle bearings in the head of a 8mm Leinen lathe. The arrangement of the bearings and spindle were as a cartridge using simple tubular spacers of slightly different lengths to provide bearing pre-load. Although the spindle was supported by only 2 bearing the same arrangement can work for 3 but, for the simplest arrangement, they would all need to be the same diameter or at least have the same OD.

The spindle would have a single diameter for its whole length the same as the bearing ID with an abutment at the front where the ER8 collet fits. There would be large tubular spacers matching the OD of the bearings and others with ID's matching the OD of the spindle. The two spacers between the front bearing have slightly different lengths that set the pre-load of the front bearings and the different lengths of the 2 longer one set the pre-load, if any, for the rear bearing. The outer tube would be be symmetrical with internaly threaded ends to retain the cartridge.

I think the attraction of this arrangement is that all the parts are very simple to make and alter if pre-loads need changing.

Some special bearings are paired with the width of the out race being different to the inner race so when assembled with equal length spacers the correct pre-load is provided. This was the case with the Leinen bearings which were £250 a pair and had to fitted the correct way around.

However it is relatively easy to shave a few thou/microns off the sleeves by lathe or stoning the inner or outer until you get it right.

CS

Thread: Squiggle motors
23/07/2023 10:19:15

For those interested there's details of these motors referred to as" Inchworm" on Wikipedia.

CS

Thread: Making an alternator that charges 'properly'
11/07/2023 10:54:58

The upper frequency limit of many VFD's is 400Hz and I've used one to test various aircraft devices that needed 110V/400hz. However I did need to exercise care as the VFD output is not isolated from the mains.

I can see that in the aircraft industry where weight costs money that powerful BLDC motors with electronic control would have improved efficiency and less weight that an equivalent induction motor. If a plane could go "all electric" it would simplify the RAT.

I know of some vintage aircraft, that were never fitted with electric, being fitted with a small permanent magnet alternators so they can use modern aircraft radio and other devices demanded by ATC.

Most light aircraft engines use "aircraft grade" car alternators and electronic voltage regulators.

CS

Thread: Workshop Clock
05/07/2023 19:34:21

As I reported earlier a workshop may not be a good place for sensitive electronics where periods of high humidity, combined with flux residue left on a PCB after manufacture may cause corrosion or leakage. My DRO readout head recently suffered from this but about 5 years ago a microprocessor based device, located in my garage, that is used by my solar panels failed. Close inspection revealed that the 32khz crystal, associated capacitors and tracking to the microprocessor showed signs of corrosion. Cleaning this off and varnishing the area has cured the issue.

Most digital clocks use CMOS integrated circuit and a 32khz crystal oscillator circuit where even microamps of leakage current will affect their operation and may reduce battery life.

What I have found is that the effect of acidic flux residue, humidity and the device power causes tin to migrate out of the solder to "plate" the PCB which is easy to see under a microscope. Once this happens only physical scrubbing can remove the plating and restore correct performance.

CS

Thread: Recent issue with DRO
02/07/2023 20:52:17

I suffered a failure of my X Pos 3 DRO readout head and the cause may be of interest.

On a recent power up the DRO appeared to power up as normal then immediately shut down. I checked the mains supply to the head which was OK so I removed the head to explore the fault in my electronics workshop. I checked the 1 Amp fuse in the mains socket of the head and this measured O/C but visibly looked OK. I replaced the fuse and the same failure sequence occurred .

So time to have a look inside. Although my machine workshop is dry and the DRO head had never suffered any water ingress there was some corrosion on the non-component side of the PCB and especially around one of the decoupling capacitors. I thought that the electrolytic decoupling capacitor had leaked but on removal it was OK.

What I believe has happened is that when the PCB was made a "no clean" flux was used in the flow soldering process. As the name implies the PCB does not go through a post solder cleaning process and flux residues remain on the PCB.

This doesn't create an issue provided the PCB is only operated in a dry and warm environment. However my workshop although mainly dry is cold and unheated during the winter so may experience occasional humidity "episodes". Another factor may be that the flux residue may be hygroscopic and when damp, having an acid component, becomes conductive. If the DRO is powered up when this condition is present then a degree of current will flow and I've seen a metallic film, possibly tin, plated between PCB copper tracks particularly where through hole components are installed.

I have seen this before so a quick clean with acetone and a hard scrub where deposits appeared more stubborn and normal operation of the DRO head returned.

CS

PS if you ever drop your mobile phone into water immediately removing the battery may prevent damage because of this issue.

Thread: Accurate sheet metal cutting
21/06/2023 18:01:31

One way to make small thin parts is to coat the thin material with beeswax , scribe the outline of the reed and then acid etch. Laser or plasma cutting may produce hardened edges if the reeds are steel. Water jet cutting works on most materials but cannot be done at home.

I believe the rate of etching can be increased electrically.

CS

Thread: Cutting Oil Fumes
16/06/2023 13:23:45

I use carbide insert tooling and also PCD on aluminium so mainly cut dry. However I have acquired some cutting oil used in a friends CNC machine shop and occasionally use that but the fumes have an unpleasant smell. This isn't appreciated if it leaks into the house through the internal door to the garage. I have notice that the oil appears to be a vegetable oil judging by the way it oxidises and goes sticky where it gets on the lathe and mill. So if it is could something like cooking oil be used and would it have a better smell. Castor oil was the best for bike racing back in the barely remembered past but the smell is still well remembered from race days at Brands Hatch.

I found that cooker hoods make fine extractors and used one I got from the dump for a small spray booth. I often see these offered on Freecycle when kitchens get refurbished so can be sourced at no cost.

CS

Thread: Toyota Hydrogen
11/06/2023 09:58:26

I think most internal combustion engines are only moderately efficient with very little recent attempts at improving this. The overall end to end efficiency of a vehicle with a ICE powered by hydrogen will be pretty low but this isn't mentioned in the video except by the remark of using "green" or surplus electricity. However if ways are found to use this source of "surplus" energy, as I'm sure it will, then the benefits will be greatly reduced.

CS

Thread: How did early Automatic gear boxes on cars work?
07/06/2023 12:48:16

In the late sixties my flat mate had a French car, I believe a Renault, which had an electrically operated automatic transmission. I believe it had a magnet particle clutch and a normal type gearbox but operated sequentially, up or down like a motorcycle gearbox, by electrical actuators.

I didn't take that much notice of it as it was a car and I was only interested in motorcycles.

I only had one ride in it as a passenger and it seemed to drive like a normal car. When stationary one would put it in drive and press the accelerator pedal and off you would go. At an appropriate speed the engine would throttle back slightly, irrespective of the accelerator pedal position, and the next gear would be engaged with the same sort of timings if done manually. If you took you foot off the accelerator pedal the car would slow and change down and I believe there was a link from the brake pedal to disengage the clutch to bring the car to a complete stop.

He did demonstrate that it could get confused sometimes if the accelerator was too on/off but otherwise it was reasonably reliable but I don't think he kept it long.

CS

06/06/2023 14:41:29

None of my motorcycles had synchros or needed then in their gearboxes. A few times I had to drive them without a clutch when the cable broke. No problem on the open road but a bit tricky in London with the traffic lights.

CS

Thread: Fitting a Huanyang P2 VFD to a Student 1800
04/06/2023 15:39:35

If a mechanical spindle brake is combined with a spindle drive clutch as fitted to a Colchester Chipmaster then the VFD won't be overloaded. In this machine the motor is started using the forward/reverse switch and drive to the chuck engaged by a separate lever activating the clutch. Pushing the lever the other way disengages the drive clutch and gradually activated the spindle brake. The Student may use a similar arrangement but with two levers, one to engage the clutch and the other to drop the clutch out and gradually engage the spindle brake.

However in a more conventional electrical control arrangement the motor may be started and stopped by a buttons engaging and releasing a motor control contactor/s and when a mechanical brake is used it would normally activate a switch that releases the motor contactor to remove drive.

Machines can be fitted with either an Emergency Off or an Emergency Stop. The EMO just disconnects power whilst an EMS arrangement actively stops the machine in a controlled sequence.

If a VFD is used the VFD can be configured to "coast" to standstill when "Stop" is activated in which case there is no regenerative braking and no need for a braking resistor. In this case spindle braking would rely solely on mechanical losses. If a mechanical spindle brake is used this would need to be fitted with a switch to "Stop" the VFD when it is activate.

CS

Thread: Catch 22
29/05/2023 09:28:03

I think the warning message in itself is misleading in that I don't know of any software that will harm a computer. However there are plenty of examples where software can harm the data stored on a computer.

Was the message generated by the OS or the Internet browser and in either case this may just be case of "don't blame us if your data is damaged".

What really gets me is that the hackers seem to be able to find the weaknesses in the OS or Apps but the so called experts with all the knowledge of the product ie the architects of the software can't or more like don't have the psychological mindset to critique their own work.

In a product development teams should there be more "breaker" than "makers" or are the "breakers" the public or the hackers.

CS

Thread: Inverter help
20/05/2023 10:08:40

I fitted a VFD to my Fobco quite some years ago. I used a 2 kw Yaskawa VFD and configured it to output a max frequency of 100hz rather than the more normal 50hz. Although the motor is rated at 1425 rpm these motors come in a 2 pole variant that run at 2850 rpm so no problem operating at 100hz. The higher frequency gives a slightly increased speed range and so I rarely need to change belt setting for the type of work I do.

It would be interesting to fit a Brushless DC industrial sewing machine motor as these are rated at 500w (3/4HP) and have tremendous torque even at low speed.

CS

Thread: First workshop
19/05/2023 10:58:33

With regard to the floor I would recommend laminate over thick insulation if heavy machines don't have to stand on it. The laminate is easy to keep swept and tolerant of fluid spills other than water and keeps ones feet warm.

I use Freecycle to source all sorts of items including materials such as used and new laminate for my workshop floor, old kitchen cabinets, work surface etc which often come up as houses get refurbished. Someone was offering a Granite work surface which I thought would make a fabulous bench top and surface plate to boot.

I recently got a 10 draw Bisley unit and a working Dyson vacuum that is ideal for the workshop to replace the one I got out of a skip 20 years ago.

All items are offered free and you can do your bit to save the planet.

CS

Thread: Recommended viewing - Artificial Intelligence
15/05/2023 12:53:38

When ever AI is mentioned I'm always reminded of the film Dark Star so be careful of what you wish for or what may be sold to you "as good for every one".

CS

Thread: Who made this Watchmakers Lathe
23/04/2023 23:30:29

The way the pusher in the tailstock is tightened doesn't look Boley.

It may be a Marco but according to Tony's site the Marco was a badged lathe the original maker being unknown.

CS

23/04/2023 21:48:53

In some ways it looks like a J E Kampe from the pictures I've seen on the lathes.co.uk site. If so it should use 9mm collects rather than the common 8mm. There may be some identification on the headstock emend of the bed.

It definitely looks like an American style WW lathe and similar to the American Watch Tool company.

CS

Thread: VFD documentation, almost useless
12/04/2023 22:21:54

From what I can see it seems the printing has slipped down with regard to the outline and terminals of the VFD outline drawing. So the top right hand 3 terminal should be U, V, W from top down.

I can see how this may lead to confusion but the VFD terminal designations do match the common format for other makes.

Ian P if you can PM me I can help correct the errors.

CS

Thread: How does this flame failure device work?
08/04/2023 10:58:07

I forgot to mention that it is now illegal for anyone to service a gas appliance that are not trained and certificated to do so. However like many thing " for the guidance of wise men (women) and the obedience of fools".

CS

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