Member postings for Richard Parsons

Unless the die says otherwise with words like ‘Start from this side’ stamped into it, ALLWAYS start from the side where the details are written ie the maker’s name, the die size etc. 

Edited By Richard Parsons on 11/08/2010 08:14:46

Hello John,

Thanks for that reference. Although I have been subscribing to MEWS since 2004 here in Hungary (and before that in the U.K.) MEWS No 108 is missing.

This would have been about October 2005. In 2004-5 the publishers of ME/MEWS were using a Swiss distribution company for the Euro Post. Summertime distribution in 2004 was bad –well there were holidays, so they would be short handed and the batch for Hungary was very small! It was forgotten –dimmed-. The same thing happened in 2005. 

Later in 2005 the distribution company was involved with a nasty swindle involving an Italian outfit. The Swiss authorities just cancelled the distributor’s licence and dumped on them from a great height. They should be ‘out’ in a few years time (with good behaviour). The Swiss are very strict.

I cannot get a copy of MEWS No 108 as there are none left. The Swiss just shredded the blooming lot and the publishers had to use up their surplus to satisfy demand.  

That is why I did not know about this article. 

If any one could scan in and message me a copy of the article I would be delighted.

I used to be interested in 1/10 scale rifles. An acquaintance of mine was building a WW1 13 pounder in 1/5^th scale and showed it at a local model show. He was nicked and given 6 months by the local beaks. He actually did 9 months in the lockup as he then went to Crown Court where the Judge directed a Not Guilty verdict as the gun was incomplete, could not chamber any known round and the use by the local police of a technicality of being a dismantled weapon was ridiculous. Had he finished the thing before he showed it and had sent it to a proof house and got a certificate of ‘Inability to Prove’ it could not have been a gun. By the way a certificate of ‘Deactivation’ is no good because to give this it means that the thing must at onetime been able to fire.

When he asked, in court, for the thing back, as it was not a gun, he found that the ‘beaks’ had ordered its destruction along with all his books, drawings etc about guns. The Prosecution claimed that the man ‘had an unhealthy interest in guns’.  Her honour the judge nearly ate her own wig in her anger. So be warned. Those who now manage us do not know or care about the law. I got rid of all my books PDQ on guns gun-smithing and any related subject I trashed all my models etc.

Edited By Richard Parsons on 29/07/2010 07:53:22

Some moons ago I wrote a challenge to the Editor on a similar topic. I what it said was that if you could read the rotational speed and (position) of a shaft (say of my milling machine) and factor this into a stepper motor which could then drive a shaft with a gear blank on it. Behold you have a gear hobbing machine.  The problem for me my ‘electronic’ stopped with the introduction of the pentode valve. Any one out there want to design the black box to do it?

The advantage of hobbing is that you only need one hob for each Module/Diameteral pitch and that is cut as Rack’. With gear cutting you need several cutters for each Module/Diameteral pitch depending on the number of teeth you are cutting.

The problem with the Savonius Rotor is that they are slow and low powered. They are cheap, easy to build, omni-directional and unlike the Darrius rotor are self starting. My pump gives me about 10 watts in a 6M/Sec wind it pumps about 40 litres/hour.

The overlap on the drums is variously 25 to 10% according to various authorities. It is a good idea to Google for Savonius rotor power output. It gets rid of the junk.

I once built two from dog food cans to get rid of moles in someone’s lawn. They had a little clicker on them which transmitted noise into the earth. Old Molewarps don’t like noise as he cannot hear the wyrms. A few days of that and they packed their bags and went elsewhere.

Edited By Richard Parsons on 23/07/2010 15:50:45

Hi   

Have a look at the thread called 'The use of adjustable reamers' I think you will find the answer to your problems.  Remembers reamers are really scrapers and are greedy beasts.  Aluminium can be sticky stuff and will clog the blades so do not try to take out too much. When compressed, the swaff, can become harder that the metal it came from. This would leave a rough surface.

Steve - Hi there. This is an old old problem. Search as you might you will not find the cause EXCEPT for the plug! Get a brand new plug. A plug will work well for hundreds of hours and then fail if it is left for any time. I have had this happen many times with garden tools, scooters, and chain saws all of which had been laid up for some months.

Dick

Many long years ago I think there were often adverts on the cover. Does it matter what is on the cover? It is what is inside that counts!

There are four ways of doing this. Three of these have been written up in the Model Engineer/ Model Engineer’s Workshop.  For your 1/8” square holes in the buffer the best method to make up a punch broach. You make a tool which slowly graduates from a 1/8” round to a 1/8” square over length (in this size) of about 25mm. You then machine a series of cutting faces about 1 to 1.5 mm apart on it from the round end to the square end. Harden it and tonk it through the 1/8” hole you have drilled. This was written up in the mid 90s in Model Engineer.

The next method is to make and use a Rotating Broach.  This was written up recently in (I think) MEWS but I just cannot drop my hand on it. Hungarians cannot leave anything alone so God knows where it is. There was this morning also a picture of the tool somewhere on this website. It will graunch out almost any shape you can make the tool for, but it takes a rigid and powerful lathe to drive it at any speed.

Third way, which was written up in MEWS about 3 years is to use a drill based on a Reuleaux curve. This uses a Warrington coupling but will not drill a pure square, the corners are rounded. I made two 1 for me and 1 for a company, which had a problem. They had a problem with a 12mm square hole in a casting about 25mm deep. It should have been cast in but it weren’t. just after they had shipped the first dozen or so Suzuki decided to send the castings back (the model was not selling).

Edited By Richard Parsons on 21/07/2010 16:57:15

Your chuck must be either larger or smaller than your rotary table.

I chose a 3” (76mm) chuck whose body was smaller than my 4” (100mm) rotary table.

Here is how I did it.

1. I took a lump of 3/8” (10mm) plate bigger than my table and centred it in my 4 Jaw
2. I drilled and reamed a ½” (12.5mm) hole right through it. This will be needed later.
3. I machined a hollow about 1/8” (3.2 mm) deep to be a nice fit over my rotary table.
4. Reverse the plate in the 4 jaw holding it from inside the hollow you have just machined using ½” hole to centre it accurately.
5. Bring up a tail stock centre to stop anything jumping out of the chuck
6. Machine the outside of the plate to bring it round.
7. Machine the face to form a stub about 1/8” long which is a snug fit into back of the chuck you are going to use.
8. Remove the work piece
9. Next make a small mandrel to fit into ½” hole and into the chucks own back plate.
10. Use this to line your  the chuck’s own back plate and your new adaptor and spot through the retaining screws to hold the chuck to the adaptor. Use counter sunk screws.
11. Finally mark drill and fit the hold down screws into the slots on the table.

I would attach a picture but Windows Vista is still playing up (Comeback NT4 ALL is forgiven). Windows software updates are not released they escape

Dusty – I agree with you PB can be the very devil, but it can be machined if you use sharp tools with negative rake, take it slow and gentle. With most brasses and bronzes most of the problems (including reaming) stem from being too ‘wholesale’ and trying to emulate ‘industrial production speeds’. Does it matter if it takes you another ½ hour to do the job? Listen to the tools a nice hissing noise as you cut and all is well and use plenty of cutting oil to lubricate the cut. 

 Andy -yes I know but this was the thread I was aiming at.

 Getting back to reamers ‘ream to fit’ Rule 8. You can always take out more but it is the devil own job to put metal back in to the hole. As the my friend the Chinese inspector Mr Wun Thou Wong says ‘Softly softly catchee monkey’

Edited By Richard Parsons on 11/07/2010 09:59:50

Adjustable reamers are really scraping devices. They scrape out small quantities of metal from holes. They are not as rigid as solid reamers and should only be used to take small cuts.

There are usually two types.  The 5 bladed reamer and the 6 bladed reamer. The 6 bladed can be measured to determine the hole size, 5s cannot.

To set the reamer up for he first cut, put the reamer into the hole and adjust it until it just begins to grip the hole. Then increase its size by ¼ of a turn of the collars. Always make sure that the top collar is tightened down. Make your first cut. Repeat this by increasing the size of the reamer by no more than ¼ of a turn of thee collars. Measure the hole frequently. Measuring the 6 bladed reamer gives you an idea and only an idea of the hole size.

GOLDEN RULES

1. NEVER turn the reamer BACKWARDS – can You break/chip a blade.
2. Never put more than ¼ turn on the collars, reamers are greedy beasts and can easily seize up. (Not nice)
3. If you get a jam loosen the blades and pull the reamer out and start again. Remember a jam will leave a number of ridges and these have to be cut away or you will get another jam.
4. Make certain that the collars are tight.
5. Clean the reamer after each pass.
6. If the reamers grips, STOP and ease/reduce the cut.
7. Do not push down on the reamer too hard or it will gripe or jam. Take it slow and easy
8. Measure the hole‘s diameter frequently.
9. On each turn try to stop in a different place.
10. Use oodles of cutting oil.

As I have very few metric reamers I use expanding reamers quite frequently.

Regards

Edited By Richard Parsons on 10/07/2010 18:09:53