What Did You Do Today 2019

Can you crimp or solder on about 1/2 of thin wall brass or copper tube to the end of the Bowden cable to stop the fraying?

Bit scary!

Big problem with using metal cable for strimming is the amount of energy stored in the spinning wire is proportional to its density and Steel is over 8 times heavier than Nylon. When a steel cord breaks it will have much higher striking power, whilst the fragments make more effective projectiles, travelling more than 8 times the distance of Nylon bits of the same size.

As the guard on a strimmer isn't as complete as a rotary motor, I'd be wary of using Bowden cable in one. It's a lot riskier than the plastic wire recommended in the manual.

Dave

I spent today preparing an engine exhibit for the rally season, I bought it last year to go with my collection of 30 VDC and 15VDC generators, built under licence by BSA to charge radio battery sets for the British military. The new one was built in America and is 15VDC and 240 VAC 85 watts, its fitted with an external flywheel to balance the rpm.

Initially I had no spark from the magneto so pulled a spare parts engine from stock and removed the coil and fitted that to the new engine then cleaned the points, the fuel system needs looking at as it will only run with full choke, chances are its the fuel filter/one way valve, then new grandson arrived so cleaned up and spent time with him, apparently I stunk of petrol.

Martin P

Hi, today I did a test lift of my Warco Major milling machine. Firstly I made a suitable lifting beam to fit the machine, which is just a 660mm length or 75mm square hollow section which is drilled at each end to take an eye bolt and a short piece of the same section was welded on the same side midway between the eye bolts. The short piece locates into a square hole in the underside of the casting that moves up and down the column. Two pieces of self adhesive rubber are stuck each side of the short section, so as to act as a buffer between the casting and the lifting beam.

A test lift was then done to test my setup and to ensure that I would get enough height for the stand needed. It may not be apparent in the photo below, but the tube that the chain blocks are hanging on, is only about 60mm or so below the ceiling, making difficult for any other way.

Needles to say, it went very satisfactory indeed and I have a little extra height to spare if needed.

Regards Nick.

Edited By Nicholas Farr on 31/03/2019 00:07:01

Nicholas and Martin -

One of the delights of the MSRVS Rally in Tewkesbury is the venue being close to the Abbey, so a striking clock, and the ringing on the Sunday morning.

I was in Alston, up in the Northern Pennines, for a weekend a couple of years ago, and was surprised to hear a definite melody from the church bells on the Sunday morning. I remembered it as a hymn-tune, but also remembered a friend who is a Tower Captain telling me tune-ringing is not done in England. (She told me this when showing me the bells in her local church, in Somerset.) So I investigated: the tower is no longer able to take manual-ringing stresses so the peal was converted to a carillon. I can't recall when, but I think it must be unique in this country.

A break from the workshop today; caving instead.

Only not quite away from model-engineering as we were using a winch I'd made from, among other materials, some lengths of scrap 7-1/4"g track rails long past their best for railway use; and I collected some angle-iron from a club clear-out to make a trolley for my small horizontal miller! (So I can push it back against a wall when not in use, as my workshop is becoming quite cramped.)

Also realising I may need thin, non-magnetic shim / feeler-gauge material for setting the Myford mill's DRO pick-ups, I went round the house with a micrometer, investigating assorted plastic items...

A lid from a "bread-grease" tub, a B&Q store-card, even last year's British Caving Association membership card (similar to a bank card but without the chip and embossing). Best not cut up the B&Q card but otherwise, all viable shim material <1mm thick!

Hi all, a few years ago a chap that I worked with tried the Bowden cable trick, 2 minutes in & a 4 inch piece detached itself & penetrated a nearby fence, end of experiment!

Meanwhile back at the ranch I stumbled on a ready supply of the black acid proof plastic used as seperators in large lead acid batteries, about an eight of an inch thick & bound to come in handy for something, which turned out to be, that after tiring of faffing about with cord in strimmers I set to & crafted a diamond shaped plate with the grooved pins that Mr Flymo used to attach the plastic blades on his machines, blades available in shed loads for pence at a car boot near you, long lasting, take seconds to change, result!

robjon44

Made some pulleys and converted the mill to Poly V. 2 step pulleys and VFD gives top speeds of 2900 or 1160. Beautifully smooth and quiet now, no rattling intermediate pulley or wheezing size A belts.

From ( in the old workshop)

to

I also made a top hat washer to centre the draw bar in the spindle bore for better balance at the new higher top speed.

Rod

Interesting Rod, been thinking of doing the same on my Sharp mill.

Do you get any 'flap' with such a long belt?

Re brittle strimmer cord, I moaned at my local mower repair place about the short life of coils of strimmer cord. They recommended storing in an ice cream tub in water. Seems to help but of course it soon dries out when left on the strimmer.

Belt flap seems well controlled even when working hard. I put this down to very low stretch, good flexibility and good wrap around the pulley ( unlike the round flexithane belt on my new milling spindle, I need to make a bigger belt cover )

Rod

I cannot answer for Rod, but I have converted two different machines to PolyVee drive and both were transformed in terms of smoothness and quiet running. On has quite a long belt run but does not flap at all.

Ian P

Many thanks for that Rod, I had put off this mod thinking I may have to incorporate an idler in the middle.

If I could be cheeky and ask you to PM me with the belt length and pulley ODs that would be much appreciated!

Regards

Peter

Today I added a new tool to my mill.

I am at the stage of painting the parts of my traction engine and for the flywheel, clamped a piece of round bar in the mill chuck as a pivot. Then used the DRO and a pen in the chuck to mark the outline of the black circle as a guide for applying masking tape prior to spray painting.

Additional colours were added with a Beugler striping tool held in the chuck.

Great day for EDMES. Signed agreement with Community Association for building our track. Of course this doesn't get it built so anyone in Devon with time on their hands is welcome to come along.

Today the tool chest I treated myself to, was delivered. I intend keeping it in the house to store all my valuable measuring equipment away from the damp of the garage/workshop.

Started cleaning some calipers and dividers I've had for years. Dunked them briefly in B&Q brick cleaner to remove traces of rust and other crap. All went well until these outside calipers were done. They had been soaking for about five minutes when PING ! The spring cracked across the top. Has anyone any theories why this happened?

Brick cleaner contains hydrochloric acid. The acid will preferentially attack grain boundaries and/or pre-existing cracks. Once the acid starts to eat away material it creates a stress raiser; result is PING.

Andrew

Man, that's neat.

How are you getting on with the Beugler? I bought one some years ago, although I haven't actually used it yet. I've heard of mixed results; I suspect that the paint viscosity is critical?

Andrew

Anthony

Could be hydrogen embrittlement, higher strength/hardness materials are more susceptible. I'm not an expert but basically the material absorbs hydrogen atoms which results in material becoming very susceptible to brittle failure and unable to sustain it's normal/design loads.

It can be cured buy heating the component over several hours at something like 200 deg but must be done very soon after the hydrogen embrittlement occurs, If not done in time then the heat treatment is not effective.

It's normal practice for High tensile components to have hydrogen enbrittlement prevention heat treatment done after various plating processes etc were the material may have absorbed hydrogen atoms.

Nigel

Edited By tractionengine42 on 02/04/2019 10:33:17

Could be, but I think Andrew's suggestion is more probable. I have a set of B&Q dividers and whilst they work they can't be described as high-quality. Not unlikely that the bow-spring was flawed from new or that it was damaged in use causing the force exerted by the spring to concentrate on a crack. Very likely the acid was the last straw: it opened the crack enough for it to propagate, and the spring destroyed itself by lever action.

Somewhere I've an interesting graph comparing the tensile strength of steel rods identical apart from finish. From memory a polished rod is about 10% stronger than an unfinished rod, and a super-fine rod is about 10% stronger again. The reason is that tiny surface imperfections can concentrate stress severely at a point, enough to cause local tearing, which further concentrates the stress. Obvious that cutting a sharp notch in a rod will weaken it, not so obvious that polishing improves them.

Polishing to increase strength isn't that common. I think because it's usually cheaper to use a bigger rod than to polish small ones that might get scratched.

Dave