Member postings for Neil A

Our experience at work with Hylomar was that the solvent would affect the O rings causing them at first to swell then, as the solvent dissipated, they would shrink to a smaller than original diameter and leak. You can try letting the solvent evaporate, but it is a bit of a hit and miss method. Mostly miss in my view and probably best avoided.

A new O ring without any sealing compound is really the way I would go. The old O ring has most likely taken on a permanent set over the years and so has lost all of its nip. I would measure the O ring groove to try and determine what the original size was rather than the old O ring.

Neil

They are not really what I would call a "differential screw adjuster". As you say, they usually have threads of different pitches and are the same hand to make fine adjustments.

These are just like the threads in the middle of a pair of spring bow compasses, or track rods on a car. As you wind the screw the "nuts' on each end are either pulled together or pushed apart. An adjusting screw, but not differential. Perhaps the description sounds more technical for an advertisement than simply calling it a left and right handed adjusting screw!

Neil

I have just finished machining the cylinder and the covers for a Stuart 10V engine. It's been hidden under the bench for years in its original packing. In some ways I could have wished I had left the length of the cylinder a bit oversized to accommodate a slightly longer spigot on the 3/4" diameter of the covers.

To my mind a spigot length of only 1/32" is a bit mean. It means that the lathe tool has to have a sharp corner as there is no room for an undercut on the diameter to clear the corner of the cylinder bore. You cannot put much of a chamfer on the bore otherwise you lose the location. I suppose that I could have cut a relief into the face of the cover rather that the diameter, but I did not think of that solution until after I had finished the machining!

As it is, I have made my spigots a rather "full" 1/32" long and intend to adjust other dimensions to suit. The 5/8" diameter spigot at the other end of the lower cover is no problem as it is long enough to accept a small undercut in the corner.

My original Stuart Turner drawings for the engine had the dimensions from the cylinder centreline to the port face and the port face to the exhaust port missing. All the dimension lines, complete with arrows are there, just no numbers. I have a copy of the original Edgar Westbury book of the build, which a got at the same time as the castings, but even he got at least one of those dimensions wrong. I notice that the latest version by Andrew Smith has some anomalies on the dimensions, so do check thoroughly before you cut metal if you are using either of these books.

Neil

Freezing point of alcohol is -114.7 degrees Celsius. Most domestic freezers only go down to -18 or there about. I don't think you will have a problem there.

I think I would try the freezer first, less danger.

Neil

I was interested to see the comments on the use of the dry moly spray, I'm not sure that at the current price I would buy another can, but you never know. The only thing that has stopped me actually using it on the change gears is the thought of degreasing all those teeth before being able to spraying it on. It needs a clean surface for it to be able to stick successfully.

I might have a go at the gears that are used for the fine feed and see how long it lasts, probably a long term test, otherwise the can will most likely stay on the shelf.

Thanks to everyone for the input, being retired, this forum is now the only place that I have to bounce my thoughts off others and get their opinions.

Neil

When I first started work in a mechanical design department the section leader, who had worked in the office since the early 1920's, quite often referred to "full or bare" dimensions when discussing a design. It was then left up to you to decide what that tolerance would be. As has been said, it harks back to the early days of manufacturing when precision measuring instruments were not always available.

For me it depends on what you are working on. In woodwork I would take it to be either one side or the other of the pencil line, depending on how blunt your pencil was. In metal work I would be be thinking more along the thickness of the engraved line on a good rule, certainly less than 1/64".

I have only really seen it used for linear dimensions, I don't think I have ever seen it used for diameters, which are usually described as "machine to a good fit", what ever that might be?

If you find it on a drawing, it is a case of looking to see how the relevant parts interact with each other and then deciding on your course of action. Model design drawings are not "tablets of stone". Unlike industrial design drawings, which require good reason and lots of paperwork to modify or change, our model designs can be modified to suit your particular requirements or machining limitations, provided that you understand how the design actually works.

I find that the use of some of these old-fashioned terms can be quite enlightening and sometimes amusing in these days of following a design rigidly to the letter. I like seeing them on old drawings, but that's just me.

Neil

I had exactly the same reaction to the Covid booster that I had on Wednesday as Mark. I was also planning to do some work the next day, but ended up wrapped in a blanket to keep warm for most of the day, my wife also had a similar reaction. I usually have no reaction to my vaccinations. I can only assume that the current preparation is a bit more aggressive than the last ones. It was a Moderna vaccine by the way.

It's a bit frustrating when you have planned to do something. Thankfully it didn't last too long.

During a sort out of my shed I can across a can of Dry Moly Lubricant Spray made by Ambersil. I have used this in the past on worm gear applications and I wondered if anyone had used it for the teeth of change gears on a lathe instead of thick oil or grease?

The data sheet gives open gears as one example of its use, it also states that it will prevent scuffing and reduce friction. It sounds ideal for change gears but I have never seen it mentioned in any of the lathe handbooks or any forums.

Does anyone have any views on its use, I'm just interested to know.

Neil

When I started using a lathe many years ago, I found 'Using the Small Lathe' by L.C. Mason very useful. It is available as a reprint now, not very expensive, from Teepublishing.

My copy is very well thumbed and nearly falling apart from use.

Neil

I don't know why someone would make that part without the support.

It might be of interest to you to search for "A0 Bonelle TCG" this is a fabricated version of the Quorn tool grinder with a built-up part. Could save some work.

Neil

It has actually been two years since I first posted this question and I had not realised just how quickly the time had past. After a lot of time wasting on my part and various "lockdowns" I finally settled on an Amadeal AMABL180 lathe, this is the 180 version with the brushless motor which I had not realised was available. I have been using it for some months now and I am quite pleased with it. It has done everything I have asked of it.

One or two things to get use to, such as the cross slide graduations being related to diameter rather than the radius of the workpiece which is what I am more familiar with. The Gates 5M drive belts are a bit of a culture shock compared to the more usual Z or A section V belts, I even checked the Gates website to see how they were rated for power, how things have progressed.

Many thanks to everyone who gave their experiences with the lathes that I asked about, it did help me with my final decision even if I did not end up with either of them! I probably did not ask quite the right question originally, I should just have asked what experience people had with the lathes. I think small lathes are always about what compromise you are happy with making. I decided that the short distance between centres was one that I could live with as I don't make very large models.

By the way, does anyone know why faceplates always have such large slots? I machined one for my very first lathe, a Flexispeed, with much narrower slots and that was the one I always used. I still have that lathe tucked in the corner, it always got pulled out when I had a small job to do and did not want to break down the other lathe.

Neil

It was too hot to do any real machining today, so I took the time to sort out some aluminium bar that I had. On the shelf behind the bar I found a bag that contained some cylinder head fasteners that I must have kept from when I changed a VW Polo cylinder head gasket about 25 years ago!

Out of curiosity I thought that I would check what thread it was just in case it was in anyway useful. It turned out to be M11 x 1,5 pitch. What interested me was the fact that I was able to see where the thread pitch had stretched as these are "torque to yield" fasteners. Well, torque to just past yield and into the plastic stage, hence only use once. I have to say that I was quite surprised to be able to actually see this just using a thread pitch gauge.

I can now happily toss them into the scrap bin in the knowledge that they are of no use what so ever.

Neil

I don't think that Loctite 638 is a suitable adhesive for flat surfaces, it is really intended for bonding cylindrical parts. Perhaps an alternative adhesive such as Araldite or maybe Superglue would be better, although your jointing faces for the upper part seem quite narrow.

I think that you will have a better chance of holding the unit together if you are able to use some small fasteners between the parts. I was thinking in the order of say three M3 each side centred quite close to the 25mm bore for the upper part and perhaps two m6 for the two lower pieces. Remember that a single 8.8 M6 fastener can give you about 1 ton clamping force.

Always problems to solve!

Neil

The Flexispeed is the same as the Cowell lathe, the grub screw in the centre of the three step pulley has to be released so that the pulley turns freely on the mandrel. Then the back gear cluster can be rotated into engagement. You may find that you get increased end float on the mandrel, I never really solved that problem on mine.

The mandrel on the Flexispeed has a reduced diameter rather than a flat where the grub screw tightens onto.

Neil

I hav sent you a message.

Edited By Neil A on 15/05/2022 20:44:42

As originally built, the Flexispeed spindle runs directly in the cast iron of the headstock. That is unless someone has already done a modification and fitted separate bushes, always a possibility.

I don't think that the rate of oil flow through the bearings is a very good indicator of the degree of wear in the bearings. The bearings on the headstock of the Flexispeed are not a complete circle, being split for adjustment at the front. This discontinuity tends to wipe the oil film off and so increase the oil flow.

I would be more interested in how much measurable movement I could detect in the spindle. Tightening the adjusting screws can reduce the free movement, but it does alter the shape of the bore a little. Should not be a problem unless it really is badly worn.

The maintenance instructions state that given proper lubrication and run below 1000 rpm the bearings should have a long life. Having said that, The speeds on my machine with the pulleys supplied by Flexispeed, North Walsham, are approximately 1420, 815, 460, 355, 203, 115. Not quite in line with their own recommendations.

The instructions for adjusting the bearings are to tighten until a resistance is felt, then back off 1/8 of a turn. Then repeat for the other bearing.

I'm sorry that this does not really answer your original question, but I have added it just for information.

A photo of the headstock bearings might be interesting.

Neil

I would recommend the Nylatron GS that Stueeee has suggested. I have used it for bushes and have also had very good results. Machines without too much trouble.

Neil

I have always used a straight 30 grade oil for the bearings on my Flexispeed.

Unless your machine has been modified, the mandrel runs directly in the cast iron of the headstock. Because of this the maximum mandrel speed should not be too high, the instruction leaflet mentions 1000 rpm, mine runs at a maximum of 1340 rpm and I have had no problem.

Don't wind the adjusting screws down too tightly, only enough to take out the play, you don't want to break anything.

The Flexispeed uses the small end of the 0 morse taper for the mandrel and tailstock. I think Cowells might be the same, but you would need to check.

Neil

You could always go out and find a branch of a tree with the right curve, just as they used to do for ships frames many years ago, to get the grain running in the right direction. But don't let anyone see you cutting it off !!

Neil

One product I have used in the past with success before painting is "Jenolite Rust Converter". Not particularly cheap, but very effective. Seems to be based on lactic acid.

They also do other treatments for rusted surfaces, but I've not used those.

Neil

Just out of interest I have measured the spindle nose thread diameter on my Flexispeed Meteor 2 lathe.

I know that mine has a 1/2' x 16 BSF thread, the thread OD is 0.497" the locating register is 0.498".

I wonder if you might actually have a Simat 101 lathe, this was a later version of the Flexispeed and has a 14mm x 1,5 thread.

One indication of which model you might have is the pitch of the lead screw, the Flexispeed is 8TPI square thread, the Simat 101 is 14TPI and I think it might be a vee thread.

There is always the possibility that the spindle has been swapped at some time to take advantage of a more readily available chuck by a previous owner, you never know.

Hope this helps.

Neil