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Member postings for SillyOldDuffer

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

Thread: New-style cover finish
21/05/2022 09:48:38
Posted by JasonB on 20/05/2022 19:42:18:

I thought subscribers would have been happy with the new wipe clean suds proof coversmile p

A foolish mistake - Model Engineers are never happy with anything!

I have more serious things to worry about than magazine covers! Old age, health problems, family issues, cost of living, war in Europe (that could easily spread and go Nuclear), energy crisis, natural resources depleting across the board, dimwit extremist politics in the ascendant, fake news, and climate catastrophe. The grim reaper is coming to my house soon...

Dave

Thread: Fix my (new) Lathe
21/05/2022 09:26:57

Interesting that responses vary from 'send it back', to 'nothing wrong'!

To the 'send it back' brigade, I'd say it's foolish to go to the trouble of returning an item and starting a commercial dispute unless you're certain the machine really is faulty. Complaining about stuff that isn't broken makes you look like a plonker and is a complete waste of time!

Buying inexpensive hobby lathes, I don't think it unreasonable for half competent Model Engineers to fix minor issues themselves and to add value by making improvements. I don't think it's smart to expect a far-eastern hobby lathe to be as solid and well-finished as a professional machine costing 6 to ten times the price: you get what you pay for. My far-eastern kit isn't up to production work, but it does more than I need of it. I'd have sent them back if any had been duff on delivery - warped bed, damage, faulty electrics etc - but no need - they all worked out of the box.

I recommend taking a pragmatic approach. Rather than starting by looking for faults, and especially not by stripping down and jumping to conclusions based on hard to get right measurements, it's safer to use the machine to cut metal and judge it on actual performance. Then focus on problems that actually get in the way, using measurement and stripping down sparingly to identify the cause. Don't fuss unless it really matters.

Be aware good results are often got from equipment that isn't in perfect order, whether it be a worn ex-industrial machine, or a warty new hobby tool. Experienced operators routinely work around all sorts of workshop shortcomings: a complete set perfect equipment isn't needed.

Dave

Thread: Thermal condution paste - none adhesive
21/05/2022 08:49:05
Posted by Michael Gilligan on 21/05/2022 06:02:53:
Posted by pgk pgk on 21/05/2022 05:30:38:

[…]

The type of thing can be seen at the video time point below, albeit that in my case there were three coolant bars going to 2 different processors.
https://youtu.be/CBdYzJOnfAo?t=547

.

It’s not immediately obvious from that short video clip, so I will just mention that those are ‘Heat Pipes’

**LINK**

...

Very educational this forum! Until this morning I assumed those Copper runs were just a simple metal conductor, used to transfer heat from a hot component such as a CPU across the circuit board to wherever it's mechanically convenient to mount a fan and radiator. Half right, now I know the pipe relies on latent heat and carries much more heat than a lump of Copper would.

Heat-sinks have always been a mystery to me: I know heat follows rules analogous to Ohms Law, but I've no idea how to design one. Big lump of Aluminium, with lots of fins, painted black, and don't assume it's earthed is the best I can do! How big and how many fins are just as wild guess.

Dave

Thread: New-style cover finish
20/05/2022 19:06:21

Sorry to hear Tim has a problem with his piles!

Going off at a tangent, measuring the difference was an engineering challenge.

  • A pair of good old fashioned pre Morton Model Engineer magazines slip at about 17 degrees,
  • The new-fangled Morton covers, probably made of recycled banana skins, slip at 15 degrees.

Disgraceful. In my opinion this is proof that the whole country is on the slide.

devil

Thread: New To CAD? No, but....
20/05/2022 13:29:20
Posted by Nigel Graham 2 on 20/05/2022 12:55:20:

... I know what I want.

And that is to use the system I have effectively, be it TurboCAD or SolidEdge, not keep starting yet another! (I'd not even heard of MOI until someone mentioned it here.)

We may all be guilty of assuming Nigel's read the Cotton Reel Shoot-Out and other recent threads!

The shoot-out asked members to explain how they would use their CAD package to develop a simple object, to whit a Cotton Reel. The purpose was to compare how they did it. From memory, apologies for any I've forgotten, the thread shows Alibre, AutoCAD, FreeCAD. Fusion 360, MOI, Solid Edge and Solid Works. Be really good if Nigel were to add a TurboCAD expose!

All the software passed the cotton reel test without breaking a sweat. However, I was impressed enough by SolidEdge to give it a go, and am doing well with it. When I have time, I'm going to give MOI a go because, of the software demonstrated, it appears to be the easiest to learn. It takes a different approach that might not satisfy all my Mechanical Engineering needs and I'm not going to look at it until I've explored SolidEdge thoroughly.

Dave

.

Thread: Fix my (new) Lathe
20/05/2022 12:58:08

Does it matter?

On a prismatic bed side-play and accuracy depend on the upper rail (or rails). The saddle slides on the rails and is unlikely to lift in normal operation because the cutting forces go down through the saddle and into the bed. Thus the clamps underneath needn't be anything special in terms of fit.

There are a few jobs, like parting off with an upside down tool in a rear tool post, and milling in the lathe, that might lift the saddle. What are you doing when the saddle lifts? There might be another way of doing the job.

Prismatic beds were controversial when they first appeared. Flat bed owners thought they were inferior. Nonetheless modern lathes seem more likely to be made with prismatic beds than flat ones. Ages ago I think MichaelG linked a document that explained the pros and cons, but I can't remember what it said.

Dave

 

 

Edited By SillyOldDuffer on 20/05/2022 12:59:26

Thread: New To CAD? No, but....
20/05/2022 10:48:32

Posted by Nigel Graham 2 on 20/05/2022 09:47:00:

...

I know "Print" might be a bit more demanding in CAD, so may need its own route.

...

Not really, but it took me a while to find out how to print from Solid Edge. Turned out to be easy! Just type ctrl-p, which is the standard print keyboard shortcut.

The menu print option is a little hidden, but is easily revealed by clicking the button in the top left corner. Look for 'Paper Print'.

Earlier in the thread Ian drew my attention to Solid Edge's "Find a Command" search box, bottom left of the CAD window. Typing 'print' into this answers the question immediately. Not perfect, but pretty good. Recommended

Dave

Thread: Vickers Bl 8 inch Howitzer cannon of 1917
19/05/2022 17:04:12
Posted by Mick B1 on 19/05/2022 16:13:26:
Posted by SillyOldDuffer on 19/05/2022 09:31:04:
...

By the by can't see the relief angles in Mick's other interesting document: page 7? Sorry if I'm seeing and not seeing again.

Dave

Edited By SillyOldDuffer on 19/05/2022 09:31:46

It only shows as 7 of 61 on the pdf page count at the top of the view - on the document image itself it's in the drawings facing page 10 as printed. There are arcs cut away to allow the swing-passage of the breech block. This will obviously have reduced the pressure limits for the closure, but equally obviously this will have to have been calculated for - though I've little idea offhand how to approach that...

blush

Here's a screengrab:-

8inchhowbrch.jpg

Looks as if there might be a corresponding bite out of the block itself too.

Edited By Mick B1 on 19/05/2022 16:27:47

Thanks Mick - obvious when the drawing is in landscape.

More geometry to making these than I realised. It's obvious that my theory about the Naval Breech coming out horizontally is wrong on the Vickers 1917, which your image shows has arcs cut to avoid fouling.

Interesting that the Naval breech is considerably more complicated than the land version. In addition to hydraulic power assist, it allows electrical firing with a safety interlock to prevent the gun going off before the breech is closed.

I wonder how reliable the obturator pads were? I'd expect a lot of flame to escape through the breech if a pad leaked.

Dave

Thread: slipping chuck
19/05/2022 16:13:55
Posted by Dave Halford on 18/05/2022 10:33:22:
Posted by bricky on 17/05/2022 21:05:37:

The drill is a startrite Mk2 and I have owned this, drill bought from a factory,Frank for 30+ years and never had a problem until now.I don't know what the quill taper is but the chuck is original.I don't take a a ball pein hammer to it but a dead blow hammer to just tap it back up.

Frank

In which case the problem may be sloppy bearings or the chuck has begun holding a drill off centre due to wear. A short taper like a J33 can't take any horizontal wobble at all.

+1 Vibration is one of the few things that will open a tight drill taper in good condition. Normally, drilling makes the taper tighter, but mine's come off a few times drilling through metal sheet and I've missed the sacrificial block of wood underneath. Since a scary incident I always clamp the job so it can't take off or spin, but without support, the drill chatters violently and then gets a sharp downwards jerk as the flutes entangle with the part-cut hole. Otherwise the chuck has to be wedged off with a hammer!

I suppose vibration caused by worn bearings, a damaged belt, or a bent pulley would loosen the taper too. As Dave says, drill tapers can't take sideways wobble at all.

Dave

Thread: Fkesxispeed...what is the back gear for and how to use it
19/05/2022 15:50:42
Posted by not done it yet on 19/05/2022 14:35:16:

What SOD says refers mostly to variable speed motors - while the majority, on older machines, are constant speed, fixed by the frequency of the supply.

...

The use of fixed speed motors on older machines is caused by the technology limitations of the day, not best practice! Now it's possible, single-phase motors can be dumped.

The electronics necessary to do this took a long time to come good. For decades fixed speed single-phase motors were the best that could be provided for domestic needs above 100W, and lesser powers were delivered by Universal Types. Both have undesirable characteristics, and they have never been popular in industry. Better types of motor are available if you have a suitable power supply. Something less heavy industry than motor-generators, Copper Oxide and Mercury Arc rectifiers, and Ward Leonard speed control systems!

Electronics have fixed the power supply problem. Today it's cheap and easy to speed control powerful DC and 3-phase motors, or - best of all - a hefty Brushless. No one needs to put up with single-phase motors and belts any more.

Although they're not complete rubbish, my advice is to consider the alternatives if an old machine needs a new single-phase motor. They all outperform single-phase types.

But I'm not trying to persuade anyone to upgrade. My point is that the need for back-gear is much reduced on a lathe with electronic speed control, even though electronics aren't perfect.

Dave

 

Edited By SillyOldDuffer on 19/05/2022 15:52:01

19/05/2022 14:02:06

Interesting debate to be had about the merits of classic back-gear versus modern electronic speed control.

Some jobs, like threading and turning castings, benefit from spinning the chuck slowly - 50rpm or less. Back gear is the traditional solution. Big advantage is gearing down increases torque and keeps the motor operating inside its comfort zone. This is particularly important if the machine has a single-phase motor.

The disadvantage of back-gear is the fiddle-faddle of putting it in and out of action. Not a problem if a lot of slow speed cutting is on the agenda, but becomes a nuisance when the work in hand involves many fast speed changes. I think fast speed changes are the most useful pattern in a general purpose workshop.

Electronic Speed Control is the modern alternative. It allows the lathe to be spun at any rate at between minimum and maximum at the turn of a knob. Very handy whenever a job hops between cutting small and large diameters, whilst switching between fast Aluminium, medium speed steel, and slow cast-iron. Unfortunately running electric motors slowly reduces their power output and they get hot: the operator has to make sure he doesn't cook the motor or overheat the electronics! The power loss at slow speed may not be serious because, depending on the type of motor, the electronics can compensate. Older lathes keep the motor cool with a cheapo impeller that doesn't work at low RPM: newer ones often have a separate cooling fan.

Basically a trade-off between stamina and convenience. I prefer the convenience of electronic speed control, but on my hobby lathe its still necessary to change a belt to get low speed. (25 to 450rpm). Speed on the high belt is about 150 to 2500rpm, which is good for most of my needs. (Including threading, done in reverse away from the headstock at 150rpm or faster...)

Given speed control, I've never felt the need for back gear, but it depends on what the lathe is used for.

Dave

Thread: mini grinders
19/05/2022 13:22:26
Posted by Stephen Follows on 19/05/2022 12:18:08:

I have gone through two Dremel grinders and a cheapo lookalike in three years. The Dremels failed due to speed control burning out and the motor burning out on the second. The cheapo gearbox fell to bits.

I don't use them heavily and only occasionally. Thought I'd treat myself to a Proxon, read a lot of very good reviews, not seen a bad one.

Having got one and used it for light sanding it suffers the problem of over heat. Gets very hot very quickly. Too hot to hold in a matter of minutes. Don't know how long this one will last. I've come to the conclusion that there isn't a good make out there.

Four of these tools in trouble suggests severe bad luck or they're being pushed too hard for what they are. What do you mean by "I don't use them heavily"?

My Dremel shows no signs of distress, but it's only used once or twice every few months for relatively light duties - cutting and polishing small parts etc. In my workshop 10 minutes 'at it' with the Dremel is considered heavy use, and then I let it cool off for at least 10 minutes before starting again.

The industrial equivalent has a separate motor spinning a chuck on the end of a bowden cable-thingy. The motor is considerably bigger than the one in a hand-held Dremel. Watched a stone mason using the same sort of tool except his was driven by compressed air - no risk of overheating but it wasn't half noisy!

Dave

Thread: Oil can (again)
19/05/2022 10:38:50

The man who invents a cheap reliable oil-can will make his fortune. Leaky oil-cans have been criticised throughout the entire history of model engineering. All mine leak a bit and spending more money may not be the answer. My least leaky oil-can is the cheapest, and it might be better because it's made of plastic and the threads squish. I don't know - the designs are all similar. Oil being slippery stuff makes it difficult to contain in a can operated at all sorts of odd angles.

Reilang have a good reputation, but even they've been criticised. I've got better things to spend money on, but be warned! My workshop isn't the clean sparkly type and a leaky oil-can doesn't make the mess look any worse. I just swipe spillages over my machines with a pair of old underpants and pretend it prevents rust...

smiley

Dave

Thread: Advice on DROs for a mill
19/05/2022 10:13:05
Posted by Howi on 19/05/2022 09:29:52:

Touch DRO using the TI launchpad is a complete working solution, why re-invent the wheel just because you have bought an Arduino. All the hard work has been done for you. You either want a working solution oir you want to design your own, one route is simple, the other can lead to a lot of frustration.

I do not know why people think the Arduino is the best/easiest solution, it is like saying I will only use a particular make of end mill rather than ones that suite my particular use.

The solution is already out there, save yourself a lot of hard work/frustration and cost, Yuri has put a lot of work into the proiject, it's cheap and it works.

The Arduino IS NOT the solution to everything.

Horses for courses.

The Arduino is popular amongst folk who want to learn a microcontroller because it's development environment is friendlier than most - it hides a mass of complexity providing beginners access to C/C++ efficiency, without swamping them with complicated details. The relatively electrically robust chipset reduces the chance of wiring mistakes causing magic smoke. And Arduino's success as a hobby platform has created a large community offering help, cheap peripherals of all sorts, and hundreds of off-the-shelf software libraries.

In terms of capability Arduino sits above microcontrollers running BASIC or Python (both useful and easier to learn but too slow when performance matters), but below a professional development toolset. The latter are hard to learn, probably over the top for most amateur purposes. Arduino provides a good balance between power, functionality, ease of use, and cost. It's a good choice for starter and more advanced projects.

When I wanted a DRO I bought one. But - out of interest and to understand how scales work - I've also experimented reading them with an Arduino. In a clean room with an oscilloscope and other tools that have no place in a mechanical workshop! Different hobby.

Although TI Launchpad is an excellent platform, the steep learning curve and relative lack of support make it unattractive to me. So far I haven't needed any of it's particular virtues. When I need more oomph than Arduino can provide, the Nucleo family does the job.

Lots of choice out there.

Dave

Thread: Vickers Bl 8 inch Howitzer cannon of 1917
19/05/2022 09:31:04
Posted by Mick B1 on 18/05/2022 20:11:08:
Posted by mal webber on 18/05/2022 18:21:53:

...

Dave that is pretty much how I went about it, although the cut outs in the breech would never work with a swing-away plug. ...

 

I think you're right that there's an issue with a hinged breechblock carrier and the arc of insertion of the block creating interferences. I'm sure I've seen drawings somewhere of the the reliefs that were used to prevent them.

There an amazing and impressive animation of the breech workings of the 15" naval gun here:-

**LINK**

... but it skates over the problem and I wonder if it cheats...

The problem would be solved if the breech mechanism moved back slightly before and whilst swinging out.

The animation is amazing, but I can't see any sign of it - though the horizontal movement might be too small. Two possibilities: the turning arm on the right cams as it rotates, and the carrier pintle unscrews as well:

breechsidecam.jpg

carrierpintle.jpg

 

pintleopen.jpg

pintleclosed.jpg

Not convinced by my own suggestion, though the comment 'Axial Vent Bolt is keyed to Carrier Pintle so doesn't rotate with Breech Screw' may be supportive.

By the by can't see the relief angles in Mick's other interesting document: page 7? Sorry if I'm seeing and not seeing again.

Dave

 

Edited By SillyOldDuffer on 19/05/2022 09:31:46

Thread: MEW No.316 just arrived - but what is that smell?
18/05/2022 10:05:52

Begs the question what should a model engineering magazine smell of?

I'd like it to be a 50:50 mix of Welsh Steam Coal smoke and hot oil. Definitely shouldn't smell of either Teen Spirit or Old Fart!

smiley

Dave

Thread: Time to Say Goodbye
17/05/2022 15:32:52

Dare I offer a satirical rant?

MEW 316 (June 2022) arrived today with ME 4691 (20 May - 2 July)

I see Model Engineer still has a plain barcode whilst MEW's is correctly tagged 'Mortons'! ME have let themselves and their readers down. There's no excuse - Percival Marshall never got a barcode wrong.

I look forward to Geoff Theasby's jokes about 'rude mechanicals' and am enjoying Ron Fitzgerald's series on Stationary Steam Engines. Unfortunately barcodes are a point of principle - you have to draw a line somewhere. Should I cancel my subscription?

devil

Dave

Thread: slipping chuck
17/05/2022 14:10:31

I'd start with a good clean and then inspect the state of the male and female tapers.

A taper spinning can do enough damage to spoil the grip until both tapers are corrected, but hopefully it's just dirt, old oil, or bits of swarf. They can reduce the grip badly too - you can guess how I know.

Reamers can be bought to fix the female tapers, but I think it's cheaper to just replace spoilt males. It's what my ex-wife decided to do about me...

Dave

Thread: New To CAD? No, but....
17/05/2022 12:15:59
Posted by GordonH on 17/05/2022 10:28:05:

SOD,

Re your no-appearing midpoint, had you locked the plane with F3?...

Gordon

Yes - I've long since realised the value of F3.

Sussed it out though! The Keypoints button on extreme right of the Hole toolbar controls what points will be used to locate the Hole. Mine - don't know why - was set to circle mid-point, which is meaningless on a box. Selecting 'All' restored normal operation.

seholenomarks.jpg

If I have any more questions I'll start a SolidEdge Query Thread to avoid confusing Gordon's effort.

Ta,

Dave

Thread: Vickers Bl 8 inch Howitzer cannon of 1917
17/05/2022 11:46:20
Posted by mal webber on 12/05/2022 23:01:00:

Forgot to mention this was not in scale with the Howitzer in size or the number of threads just a practice run at trying to figure it out , lots of lessons learned by trying so will see how the second attempt will go.

Thanks Mal.

Nonetheless impressive! How did you go about it? There are two stepped threads and a blank sector:

My guess.

  1. Bore the breech to suit the inner thread diameter and cut the thread conventionally.
  2. Broach the second and third sectors,
  3. Cut the second thread group laboriously, one at a time, over 60°.

Doable, but tedious skilled work; I'd get bored and mess-up. Is there an easier way, or am I left slack-jawed in amazement again? Plenty of good work shown on the forum, but your Howitzer is ticking all my boxes!

smiley

Dave

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