Member postings for KEITH BEAUMONT

I have just tried to answer most of the queries, at some length, but when I went back a page to read some of the answers my new post vanished, This has happened previously and I would like to know what I am doing wrong.

The lathe is a Clarke 300M mini lathe. I have checked the earthing of every part 4 times now and am happy that all is correct. I cannot see any signs of chaffing of any of the wiring. I had been using White Spirit as a lubricant, but as this was the final polishing fine cut ,it was dry. The only swarf that was near the tool was from this pass and was very fine and lacy. The "event" happened half way across a 1 inch diameter, so the tool was already in contact with the item. No marks of the flash were left on the item.

I will, tomorrow, stop everything and take the board out and have a look underneath. I am looking for physical signs of failure, but other than a multi meter I have no means of checking whether a capacitor is half failed, as suggested.

Keith

If it was caused by  something with the H15 aluminium, would that have created a situation that blew the fuse also? The lathe has an overload trip and on the few occasions when I have stalled it for some reason,the overload device has tripped out. I have not had reason to change the fuse for many years. So far as the event is concerned, I remember the flash of flame to be yellow and the burning of the lacy swarf to be almost instantaneous.

Keith

Edited By KEITH BEAUMONT on 14/08/2019 09:32:52

I have had a second look at the electronics board and it is perfectly clean with no sign of any over heating. The flash and explosion,for that is what it was, was definitely at the tool tip, hence the burning swarf. The bang was so violent that I was still feeling the effect over an hour later.

The loading could not have been lighter and still be cutting.Low feed,fine cut and new tool tip rule out any chance of overload, surely. Everything is working perfectly at the moment, but I will admit to being somewhat apprehensive. I have now started to make the crankshaft, with high tensile steel, so hope I do not get a repeat.

We clearly have a mystery here and I thank you all for your input.

Keith

I have this morning, checked the earthing of the lathe by connecting the earth on the 13 amp plug to every bare metal part of the lathe I can see and getting a positive ring on my meter.. I also have one of those plugs for checking correct earth on 13 amp ring main sockets and all sockets in the workshop and house are correct.

Emgee,The lathe fuse is 6.3 amp HRC, 20MM cartridge.

Farmboy, I do not have a consumer unit . Still with original fuse box.

Brian, The discharge did not damage the tool or the workpiece,other than to ignite the swarf on the tool. Would your suggested mix up with the metal cause the fuse to blow?

Keith.

Thanks for that Phil, I will certainly get things checked out,as you suggest. The bang was very loud and the lacy swarf at the tool tip burned. It was not a "pop" that you get when a fuse blows. The failed fuse did not show visual signs of burning out..

Keith.

I would appreciate peoples opinions and possible explanation of the following.

This afternoon ,machining the aluminium prop driver for a model aero engine I am making, taking a final light facing cut, 400rpm,slow hand feed, there was a sudden loud bang and a flash of flame at the tool point and everything stopped. I checked the lathe fuse and it had blown. Replaced it with new one and all started working I then switched everything off, took the cover off the electronics,suspecting a stray piece of swarf had shorted something, but all looked clean with no smell of burning, so I put it all back together and continued where I had left off.

I am completely mystified. The tool was a brand new,shiny tip for ali. cut was about 3 thou, slow feed and was about half way to the centre of 3/4"dia H 15 aluminium, so friction was minimal.

Keith

Is "Float Glass" still made by molten glass being floated on Mercury? I can remember reading an article some years ago from Pilkington the glass makers, describing how this technique was far cheaper than the traditional way of making Plate Glass.

Keith

Very early on in WW2 was formed the Machine Tool Commission, tasked with listing all the machine tools in the Country, down to small commercial workshop/Garage level. It had the power to requisition any machines not being used and transfering these to places that needed them.It was quite common for Garages to be given contracts to make engine parts,etc. I started as an apprentice with Drummond Bros in 1947 and they were still proud of the fact that their senior design engineer had been on that Commission from the start. One of the decisions made by them was to move the production of the Drummond M to Myford, to free up production space at Drummonds for the large auto lathes and gear shapers that was their main products.

.Keith

Thanks for the replies. I was begining to think I might have been caught out with a nasty.

Keith

I have received an e-mail from Alibre saying that the latest update of Windows 10 contains a bug that makes Alibre Design and Atom 3D unusable and that downloading Alibre 2018,2 corrects this and is required for all that update Windows 10.

My Pc has already updated to the latest version of Win 10, so I have installed the updated Alibre 2018,2.

My Norton Virus software advised against it ,saying it has insufficient knowledge of its safety..

I am suprised that no other mention of this has been noted on this forum and I hope I have not walked into a problem.

The download does not delete the previous version ,so you get another 372 MB of disc space used.

Keith

I have a British designed and made Merco 61 mark 2 engine of 1965 vintage. It was the stunt engine to have in those days, powering the first three planes in the world championships of that year and that has cheese head fixings identical to my mystery engine.

Keith

Edited By KEITH BEAUMONT on 24/09/2018 20:30:47

Help Jason ! I thought I was loading four photos of this engine.

Keith

Recently I was given this engine. It has been in an open box under a bench in a friends shed for 40 plus years and was in a very dirty state. It cleaned up very well and after a strip down and rebuild it is in very nice condition. Surprisingly there was no corrosion inside.I have searched various engine galleries without finding any engine that looks the same. The crankcase has been machined from solid and there is no backplate,so all assembly is through the front..The thin walled steel cylinder has integral cooling fins and two inlet ports plus a boost port through the piston Front bearing is plain but is a light alloy bush not bronze. The prop retaining flange is very unusual in having a series of drilled holes that look as though they have been drilled free hand. The plastic bodied carb has a brass disc with + / - engraved ,to alter slow running, something I have not seen before. Other than the curious prop driver all machining is first class and I wonder if it was a prototype, or a short run manufacture. I will be interested in anyones thoughts and opinions if your memory goes back far enough.

Keith

Edited By KEITH BEAUMONT on 24/09/2018 17:11:39

Edited By JasonB on 24/09/2018 17:25:14

Most of the backlash is not caused by the screw, It is movement of the two fixing screws that the instructions tell you to just nip up to tilt. Ignore this. Wind the slide fully back. loosen all three screws. gennly tighten the centre one and then tighten the other two,gradually in turn until they are tight. This will prevent any movement of the screw nut when winding.

Keith

Robin

,Machine cone as before,part off at half length. Repeat for second half. Super glue the two halfs together.

Keith

Thank you all for your comments.

Neil, The test stand is as Rod mentioned. I found the cap head screws on the left side got in the way of the throttle arm in a lot of cases ,so I c/bored them flush on that side.

Clice B, Good luck with your Vee twin. If you have not already done so, I suggest you read my previous where I relate my problems with compression ratio and the need for long nuts to hold the heads down.

Keith

Hi Geoff and Emgee.

The prop used at the moment is a 12" x8", which is the only one I have at this sort of size at the moment.

When flat out it nearly caused a crisis, pulling the workmate stand across the floor, hence the sack of rock salt laid across its base. It clearly has a lot of power.

Keith

Thanks Rod.

Keith

Have recently finished the Jones .605 glow engine.Pictures should be below. Castings and drawings from Hemingway kits.It is an 80s design,before the requirement for silencers, but I did a small mod to allow the fitting of a standard OS unit, which has taken that ear splitting crackle out of the engine sound. Pity, but I have to think of my neighbours It is a thirsty beast while being run in. A 6oz tank full gives a 5 minute run time. So far It has clocked up an hour of rich running with 5% fuel. An occasional 10 second burst flat out registered just over 15000RPM,so the Schnuerle porting, the setting out and drilling / filing of which, certainly strained the grey matter, must be in the right places, It is an easy starter,and was quite easy to get the needle valve and throttle settings about right. I am at present trying out different plugs.

If there were a longer reach plug available in the 70s it might suggest that the Jones .605 build notes. which were published from 5th May1978 in ME, did in fact refer to the use of a "long reach"plug. The combustion chamber is dome shaped and has plenty of room for it to protrube. Interestingly, the Chenery Vee-Twin four stroke,of 1983 vintage,also qotes the need for "long reach" Chenery originaly ran the engine with spark ignition,but due to comlaints about it interfering with TV , he changed to a long reach glow plug with no problems. My experience with the the one that I have made is that fitted with the OS F type plugs it would not run continuously. Machining 0.030" off the heads was the answer.

We still have no explanation why Aero plugs just have the type No on the packaging,but model car plugs, as per my OS LC3, have "long reach" on the packet, although they are same length as an OS No 8 aero plug

Keith