Member postings for Terryd

Hi Graham,

You are truly optimistic if you think that 6" diameter tube of those dimensions will be anywhere approximating round, good luck,

Regards

T

Hi Jason,

Wouldn't it take a bit of cleaning up though if it is to be a component on view, say in a Stirling cycle engine which appears to be the sort of application from the drawing.

Regards

Terry

Hi Matt,

I'm not giving here any recommendation but can say the following with some experience. I have used Posilok and ER collets and can vouch for the holding qualities of the latter. A bonus is that not only can they be also be used for work holding but they are not dedicated sizes as are Posilok collets. It is often forgotten, especially by amateurs that ER collets were originally designed specifically for milling cutter holding and it is the ability to comletely collapse along the whole length of the collet on to the shank that gives them such holding powere whereas normal collets close on a relatively small area due to the cone effect i'e. it is only the end of the collet that actually locks onto the shank when closed..

Regards

Terry

Hi Andy,

Properly applied TiN coatings are long lasting and do not wear off. TiN is in fact a very hard wearing ceramic, not a metal. It is the poorly applied coating on cheap tools which wears off, probably by not reaching the very high temperatures needed for proper deposition. Perversely the thinner the coating the better, as the thicker coatings can flake. It is calculated that TiN coatings can help the tool keep its edge for more than three times longer than normal and it has a plus that it prevents metal deposition during machining causing the phenomenon known as a 'built up tip' which can be a real problem in turning steels and other tenacious materials.

Of course on re sharpening the coating is removed but that merely means that the HSS core is exposed as in uncoated tooling so nothing is lost. 'Throw away' tooling is essentially a term used for industrial (HSS and carbide) tools where re sharpening is not cost efficient, most HSS types can be sharpened by an amater using a tool and cutter grinder, hence the second hand market in these.

I have good quality milling cutters and drills which have seen quite a lot of 'action' without any noticeable reduction in the TiN layer.

Best regards

Terry

I would agree with John. If you try to drill one slice of material you will likely get a triangular hole, especially on the larger ones. Use a good quality superglue, not a Poundland 'five for'.

Regards

Terry

Cheers John,

But I've already used too many of those .

I must admit, despite trying to stave off ageing (tried to give it up with smoking but no deal ) I am the one on the left, the other is my first grandchild, now 3 1/4 ,

Best regards

Terry

Edited By Terryd on 11/11/2012 12:33:34

Hi Bill,

You do need to surround the job with refractory, this will retain heat allowing for a quicker temperature rise (so's not to exhaust the flux) and a better spread of heat throughout the job. The best refractory is not normal firebrick or old storage heater bricks. These are intended to absorb heat and relaes it slowly, it will take a longer time to heat the job and can lead to flux exhaustion. The best refractories to use are the softer, white refractory bricks containing a high proportion of perlite (not pearlite). These will absorb little heat and reflect much back into the job, as a reverberatory furnace does thus shortening heating time and saving gas as it is more efficient.

By the way, solder will follow the heat, experienced professionals will heat the whole job, then concentrate on a small area to start the solder flow and move the flame around the joint to be made and the solder follows. In silversmithing for example it is important to use as little solder as possible while obtaining a sound joint. Work will be ruined by the excess solder that I see in model boilers. It have often seen model boilers that look as though the maker was trying to increase the thickness of the end plates with silver solder . I know that the working pressures are not the same but no one want to be scalded caused by a failed joint on a coffee pot or hot water jug handle - yes, silver ones are still made in the great British tradition

Best regards

Terry

Hi Chris,

Glad to be of some help in clearing the fog, but sorry about the multiplicity of posts. As I said my PC was acting rather strangely last night, perhaps it was tired. In fact I had to restart it on several occasions.

There is an error though in my main posting in that I inadvertantly wrote that the metal used for the matrix is Tungsten, The usual material for 'cementing' tungsten carbide for 'sintered' tooling is cobalt. Sorry about that but my only excuse is that i was also tired at the time. Also, TiN coatings are used on Carbide tooling at times, especially on 'inserts' hence the gold colour you often see. Other coatings are also used - often based on titanium, which explains the other colours that you see, but the basic material, tungsten carbide,is the same.

The problem is that users often shorten names, hence machinists (and catalogues) will properly talk of Tungsten Carbide while others call it just carbide, it is the same with Titanium Nitride (TiN - not Tin), which is often just referred to as titanium coated. Despite the howls of indignation to some of my recent posts, I still think that such confusion as yours could be avoided by proper use of terms snd good spelling.

By the way, 'sintering' (sorry to introduce another term) is simply the act of heating powdered materials to high temperatures under pressure, this bonds the matrix together. It is also described as 'cementing'. With Tungsten Carbide tooling, TC powder is mixed with say cobalt powder and heated to very high temperatures at high pressure in moulds to form the tips that you see in catalogues.

I hope that explains a bit more of this technology and is not too confusing. But my advice is to stick to HSS tools and learn to grind them, it is quite simple - see here for a useful guide.

Best regards

Terry

Edited By Terryd on 11/11/2012 11:59:19

Another rogue post

Best regards

Terry

Edited By Terryd on 11/11/2012 00:25:09

Hi Chris,

Sorry about all of the postings, I think I might have caught a virus - PC gone a bit haywire

Best regards

Terry

Edited By Terryd on 11/11/2012 00:24:29

Hi Chris,

Sorry about this it will be an essay but I hope it makes sense and helps.

HSS = High speed steel. A special tough, high carbon tool steel usually alloyed with cobalt (a metallic element, hence cobalt steels) which gives it high wear resistance. It is used for many tools including drills, milling cutters,lathe tools etc. It needs special high temperatures for hardening and tempering and will retain its cutting edge even when running red hot. It was the general; purpose tool steel until the advent of carbide tooling. It is also available as round or square sections to grind your own lathe tools etc but can be bought in preshaped sets for use on lathes etc.

TiN = Titanium Nitride a very hard ceramic used to coat tools, especially HSS tools to add extra hard wearing propertiess to the tooling, it is that gold colour you often see on milling cutters and twist drills these days. It is the same as titanium coating. because of its gold colour it is often used a coating in jewellery. Sometimes only the high wear areas such as the tips of drills are coated

Carbides are carbon based compounds which are very hard but brittle. They are mixed with metals, pressed into shapes and heated until the metal melts and cements the carbide particles together to form a very hard but less brittle matrix. hence its correst name is cemented carbide. The metal gives toughness to the matrix i.e. it is less brittle. Tungsten is often used hence 'Tungsten Carbide'. This is still quite brittle so small tips are brazed onto steel shafts which absorb the shock loads somewhat to produce carbide tipped tooling. Shaped tips which have several cutting edges are often used in lathe and milling tools and when blunted can be turned, or indexed and the next cutting edge used, they are held on a steel shank with special screws. Hence replaceable, indexible carbide tipped tooling.

Many folks use carbide tipped tooling these days but it was really intended for high speed, fast metal removal, production work, the fast removal shortening production times It is quite expensive (at least for me) but in production work the cost of tooling is negligible compared with production time and labour costs. It is not usually worth trying to sharpen carbide tooling,

I prefer HSS tooling for my lathe and mill as it is relatively inexpensive, easy to keep sharp and gives excellent finish on smaller lathes etc. It is easy to touch up and keep sharp once you have learned how to grind the angles, but as only a few basic shapes are required for the vast majority of the work we do this is not difficult.

Best regards

Terry

Hi fizzy,

When I had a garage workshop fire a couple of years ago the firefighters were only worried if there was any acetylene in the garage. I had Propane, Butane and Argoshield but they were not bothered about those. Acetylene bottles can be very nasty in a fire. We used oxy acetylene gas welding at most of the schools I taught in and we had to keep the bottles in a ventilated lean to with the gas piped in, and of course flashback arresters.

I was fully insured under my household policy and the Insurance company had no problem with my bottles. However my insurance policy for contents actually covered all losses in detached outbuildings as well as the main house up to the limit of the opverall cover, in my case that is £75,000, while many only offer limited cover for out building contents - £2000 or £5000 are common limits. it is well worth the extra few pounds a year to get that extra cover, you should also make sure that the overall contents cover is high enough.

Best regards

Terry

Edited By Terryd on 10/11/2012 12:26:54

Hi Norman,

when you do get a video - no need for a camera now that most mobile phones are very capable of good video - the best way to post it here is to upload it to YouTube and then get the embed code from Youtube and use the icon above the message compose box to embed the video here. If you're not sure how to do this just ask. Here's an example

The OP asked what steel is weldable and machineable and did not state the application.  In the absence of an application I would not suggest using the wrong spec. Using his keywords  a simple search found the information below in just a few seconds, It does not take an expert to understand it.   - click on the image

Learning to research in the quest of knowledge is the best education, too many students now only know how to 'ask teacher' which is one reason we fare so badly in international education tables.

Best regards

Terry

Edited By Terryd on 10/11/2012 12:00:55

Hi Graham,

If the Meccano Bush wheel o/d is large enough for your needs you could modify the boss by filling the existing bore by silver soldering a bit of 4mm brass in there and re boring to 1/8", otherwise open the bore to say 6mm and make a suitable sleeve, Loctited in place. You could always make an adaptor with a bit of 6mm brass, blind bored to fit your motor shaft and the end turned to 4mm to fit the Meccano boss, or drill out and remove the Meccano boss and fit a home made one.

If the 'bush wheel' isn't large enough, 2" dia or larger Meccano sprockets which have holes are available for a couple of pounds, again you would need to modify the boss, you could use a circular plate and add a home made boss. the bosses on used Meccano parts are often loose and collectors fix them by spreading the end of the boss with a steel ball using a vice as a press (fit a grub screw to prevent the thread collapsing), or with Loctite.

PM me if you would like to try some of these solutions, I could find a few bits for you to experiment with.

Best regards

Terry

Hi Mike,

As most people know, I am omong the first to offer help, and the link in my previous post actually took the OP to the correct information which I took the trouble to find for him. As only 10 posts are on show here on the home page the great majority of folk ask for help which is not available elsewhere or is very difficult to find. Steel specification table etc are widely available. I must admit I wouldn't be minded to offer help to you if you ask what tap drill you should use for a given thread just because you couldn't be bothered to find a table , but if you were lost on a machining technique etc that would be a very different matter.

The OP had already consulted steel specification tables to find out that EN1A is unsuitable for welding and I am sure that a little extra research would have found his answer very quickly and not have to wait a day before finding the information.

Best regards

Terry

Hi,

Being as you found EN1A unsuitable on the suppliers specification list why not try there, or Google it and you'll get the answer in seconds. One search ("weldable bright steel" - 5 secs) found this - scroll down.  I really don't understand why folk don't try Google first, I feel that one should only post here when not able to find an answer elsewhere.

Terry

Edited By Terryd on 10/11/2012 07:43:36

Hi Chris,

The reason I am looking at the 'Brooks - Stent' is that it can be built from readily available stock materials so no expensive castings. I can add to the bits as I wish and when can afford to buy the odd esoteric materials such as precision ground bar. I suspect that my version will differ somewhat from the original though in the cause of economy.

Best regards

Terry

Hi Chris,

more food for thought, Harolds book is here for a good price (new). I have built the HH model and it is quite good but I intend to build the Brooks - Stent, which was serialised in MEW numbers 16 and 17 or thereabouts, as a project. There is a build here.

Terry