Member postings for thomas oliver 2

The toolrest looks Pultra style and some of of the collets look decidedly like my Pultra tailstock ones, which have an exact 8mm shank, but the thread might be 7mm x 0.6mm or 17/64in x 38tpi. Some Pultra watchmakers lathes also had this size in the headstock.. My collets are stamped "Conflex" and the size in mm on the end face.

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If you want a complete record of all threads, go to the www.watchman.dsl.pipex.com/thread,html website and download the 8 pages. Measure diameter and tpi and go list to identify any thread. I have a small Dormer Tap and Die handbook. In the Metric Coarse list a 3mm thread is given as 0.5mm pitch. In the Metric Fine list 3mm has a pitch of 0.36mm but under this is given 3mmm with a 0.6mm pitch which is coarser than the coarse thread, Similarly 4mm is given with two pitches in the Fine list, the second again being coarser than the 4mm coarse pitch Can anyone explain this? The 3mm Coarse at 0.5mm pitch is decidedly a fine thread. I have never come across a 3mm Fine thread yet. The 6mm Coarse is decidely a coarse and hence a weak thread, but some Chinese engines have the 6mm fine thread used on the carb, intake.

10 UNF thread is a few thou bigger than 2 BA and 5mm is a few thou bigger again, but they all have virtually the same tpi.. Thus a 10 UNF screw will fit a slack 2BA thread etc.

It seems to me that my favourite method of cleaning up rusty nuts and bolts - using a steel wire wheel on the buffer has been used here - witnessed by the rounding off of all sharp edges T. O..

Surely even if a nyloc nut has been used, it can be used again, provided that it goes back on stiffly. The same applies to the other types. If they are doctored and go on tight , then they are unlikely to loosen off. The proof of the pudding is in the eating.

Many moons ago, there was an article in the ME mag re a New Yorker who renovated a small twin cylinder steam engine and fitted it in a quadricycle with motor cycle wheels. He took it out into the New York traffic. When he stopped at the first lights the other drivers were shouting comments like "where did you get the big rollerskate". The laugh was on them as when the lights changed, they were out dragged easily to the next lights.

Loosenut, if you observe the 3rd shot from the bottom you will note that the top of the legs looks as iff the trunk guide has been cut away.. The tops of the legs look peculiarly thin.. On closer observation, I note that in fact the feet of the original casting have tapered packing fitted to achieve the correct splayed angle.

I note that the feet of the standard are tapered and the legs wide spread. It appears that the standard may have been adapted from say a Stuart 7A and split and splayed out to fit a diiferent base. It looks like a Bitza.

There should be a little lever on the top of the dashpot which oil.when rotated controls a disc valve and the lowering action. The oil is not too critical - I think I used ordinary engine oil. My machine is well worn but still ploughs its way through thick steel. The addition of outboard support allows the cutting of short lengths a la Myfordboy design. A piece of equal diameter material in the jaws also helps to grip short lengths.

Sorry - I see the point has been covered, except that all said lecturers statements were backed up by experimentation and measurement. One such that I performed mysellf was to prove the validity of the 118deg. angle gorund on twist drills. This turned out to be the angle whiich gave penetration with the least downward force.

My lecturer at Tech College was well esteemed and he had an explanation for the advantage of rear parting. In normal front parting the reaction forces are against usual less sold casting above the front bearing, In the rear parting mode, the reaction is downward into the more solid casting of the headstock which reduces vibration and chatter.

It is not too difficult to mathematically determine how much packing would be needed under one jaw of a 3 jaw chuck to hold square stock centrally, based on square root of 2. I have done this on occasions. Another method I have used it to machine the corner off one of two short pieces of steel angle to achieve the same result.

It is not too difficult to mathematically determine how much packing would be needed under one jaw of a 3 jaw chuck to hold square stock centrally, based on square root of 2. I have done this on occasions.

I think you will find that the round stays of the average umbrella are 8BA size exactly - if you can find one on the local scrap dump. 2.5mm MS welding rod is the correct size for 7BA studs which are widely used on the smaller Stuart Steam Engines.

For a neat result the cleading needs to be tapered in section to fit on the round boiler. I once witnessed a demonstration of cutting wood for a scale Sopwith Tabloid on which the finish ot the wood straight from the small saw table was superb. The saw blade was actually a 3 in metal slitting saw. I had this problem for a boiler about twice the diameter of the Stuart. I fitted a 3 in. narrow slitting saw in the lathe chuck and rigged a table to fit in the 4-way toolpost. I achieved a similar finish and the strips fitted nice and closely together.

It seems that none of you are model flyers as glo-plugs are obtainable in both 1.5v and 2v - the latter being operated from a single lead acid cell. Most 1.5v plugs are heated with a single sub-C cell which provides more current and is very adequate.

S.H.Muffett - very high quality gears.

I support the last post for John Ward. I bought a slotted crsoss-slide from him some years ago and it was very well made and half the price of another well known firm.

Rings must be expanded by the absolute minimum. To do this, cut three narrow strips of tinplate and make a right angled bend near one end of a short length. Arrange the strips aroung the piston then slide the ring down over them. When the ring is over the groove, remove the strips and the ring will spring into the groove.

I obtained my castings supplies from a firm called Foseco way back. I never had a sign of pourosity using their degassing tablets over many years, and the sand was Mansfield sand. I did not like the oil bound sand as it was smelly, got burnt and a lot was wasted. One or two pointers were omitted from the description. To prepare the sand water is added until a squeezed handful of sand will just fall into two halves. If it stays together it is too wet. If it crumbles it is too dry Split patterns are easier to use than doing it oddside and useful for repetition. After placing the drag upside down on the moulding board, sifted with parting powder from an open weave bag. Half patten placed in and sifted with powder from an open weave bag. I then used a household cooking seive to seive sand until the pattern was covered, then I just chucked handfuls of unseived sand until half the box was filled then a gentle ramming with a broad rammer. I always got an excellent finish to the castings by seiving. Drag then fully filled, rammed. and "strickled" with a straight edge. Box reversed, pins located, gates cut with a tiny trowel made from tinplate and top box located. A little rubber blower used to remove surplus sand around the pins. Also used to get rid of any unwanted sand inclusion inside before closing up. Sharp edges to be removed as far as posible from the in and out gates to using forefinger, to stop the molten metal washing sand into the cavity. Cope and top pattern put in place, sifted with powder, filled and rammed. When boxes are opened a cavity is cut below the runner to form a little reservoir, and the top opening is tapered out to make a funnel shape and help pouring. To remove pins and pattern, the pattern is "rapped" to loosen then very carefully lifted out. The runner and riser can if necessary be extended upward with tubing to give a better head. Boxes should have peripheral key strips inside to stop collapsing of the sand. You may note that commercial boxes are fluted for this purpose. A leather apron and gloves are useful for safety and a full face visor. I got good results at first with some old pistons broken up in a sack with a large hammer. I hope the additional pointers will help beginners and add to an excellenty shot listing.