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Member postings for Ajohnw

Here is a list of all the postings Ajohnw has made in our forums. Click on a thread name to jump to the thread.

Thread: Engineer's Blue
21/10/2015 22:20:34
Posted by duncan webster on 21/10/2015 21:39:33:

Rouge is iron oxide, not lead. Still widely availabl in powder form. Don't know how finely it is ground. Also used as a very fine abrasive for polishing.

I didn't say it was.

As far as iron oxide goes it's available very finely ground. One of the rock people on ebay has it but seldom sells as it's so messy. 1 or 2 um, maybe less as I can't remember. Hence the raddle I used been based on red led oxide. It's not messy and doesn't stain.

John

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Thread: Honing HSS tools
21/10/2015 19:12:02

OTT lapping ? Maybe not if I could automate it.

opticalalox2umlappedtantung.jpg

It's tantung not hss but that makes no difference. Where it's black no light was reflected back into the camera, the surface is too smooth to do that. The shiny part of the side just shows a reflection of the surface it's on. The scratches on the side are the remains of what was pretty fine grinding. The scratches on the top from the stone I use. The shine was put on with 2um aluminium oxide. 3/16 sq toolbit. It now cuts paper pretty easily.

John

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Thread: Damascus steel
21/10/2015 16:14:53

This is on original Damascus steel - the real thing. with plenty of technical detail.

**LINK**

This also mentions it along with the same problem, no one really knows how it was done and also the modern european way of making it - or something simllar

**LINK**

John

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Thread: Myford lathe values.
21/10/2015 15:46:43

There is more than one value - if in poor condition often less than what people pay for them.

Asking for a value borders on the how long is a piece of string question - it varies.

John

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Thread: Motive power for a toolpost spindle
21/10/2015 13:43:53

The er16 collet holder arrived today. There are only a couple of ebayers selling er16 C16 200mm extensions. I went for the one with a hex nut to avoid special spanners. Much to my amazement the shaft is only a few microns out from 16mm. -5 at one end -1 at the other and a bit of a bulge in the middle that may be +1. The end where the main bearing would go shows the least error.

Only thing is that 16mm bore ball type bearings are thin on the ground. Weird as there are loads of 5/8". There are needle rollers but given how well Pultra bearings last if looked after I am wondering about sintered bronze. Maybe over 16mm bore and include a wear sleeve. That would just need a collar and thrust bearing at the other end. There are plenty of 16mm oil seals about.

John

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Edited By John W1 on 21/10/2015 13:44:48

Edited By John W1 on 21/10/2015 13:45:53

Thread: Damascus steel
21/10/2015 12:20:24

I understand that damascus blades were made in a similar fashion to the samuri ones Clive. A mix of iron and steel. Shotgun barrels too but the mix of sizes of iron and steel forged up were far more complex to get the various patterns. Some are then chemically treated to get various colours. There is an interesting example part way down this page. Might be called OTT damscus steel - done for ornamentation. It's initial aim was to combine the properties of the metals used.

**LINK**

John

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Thread: Honing HSS tools
21/10/2015 12:09:24

There are some white aluminium oxide slip stones about that will do it. Some are sold for dressing diamond wheels.

You will find what is needed by googling slip stones. The one I use is dark brown/orange, 3/8" square and about 4" long and rather fine. The white aluminium oxide ones are generally coarser. The best type is often called india stone.

The diamond hones are fine but at their best used with honing oil. The slip stone clog up with hss over time as they are usually used dry. The diamond hones can be used to clean them up.

The one I use is probably natural India stone. It knocked a big hole in my tool bonus when I was an apprentice. Various grades of aluminium oxide should be as good. The modern version can be bought here

**LINK**

John

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Thread: Damascus steel
21/10/2015 11:34:05

The OP might find some info around here or could even ask the person who maintains the site

**LINK**

It does mention the early use of citrus fruit juices. There may be more info around.

I used to shoot shotgun with some one who use one with a damascus steel barrel and thought there might be more useful information in that area. He was a brave person. The barrels have been known to burst. It had a semi shiny finish. Some others are rather spectacular. Very light and too much kick as a result for my tastes.

If I became interested in this I would want to forge my own mix of irons and steels.

John

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Thread: Newbie with an old Boley lathe
21/10/2015 10:43:26

winkWondering why some one might do something like that - maybe to get 2 levels of leverage for different drill sizes that fit well in the hand. Maybe they didn't need the one on the end or couldn't be bothered to fit a knob.

Noticing your post after I made this one - not sure I would do anything about the handle either - rather use the lathe and sort out any problems.

John

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Edited By John W1 on 21/10/2015 10:46:37

Thread: Damascus steel
21/10/2015 10:31:22

I'm sure it would leave a dull blade Jason that will also rust pretty quickly. Even the fumes can do this.

From watching Samurai I wonder if the OP has the process wrong. I'm thinking in terms of the bags of talc used on the blades. Maybe an etch is used and the blade then polished. The etch will enhance the pattern and then it's a case of how much so that it's still visible after polishing. I would have thought that there was some correct info on the web some where. Try searching with a .co.uk on the end or .fr if you can handle that language.

I'm sure I have read that quenching blades in people's bodies is a bit like case hardening.

John

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Thread: Newbie with an old Boley lathe
21/10/2015 10:14:48

I wonder who bent the lever on the tail stock ? I think I would get it off and straighten it. Like many of this style the tail stock has a nice long stroke.

If Paul wants to get rid of the chatter he would be wise to find some one who is capable of finding out what is causing it. It might be just a case of adjusting the slides so that there is a VERY slight drag. The other cause when some one hasn't used a lathe before can be blunt tools and or too fine a feed. More general play means that heavier feeds / deeper cuts are needed to get rid of it but that can only go so far. Above centre tools can also cause chatter especially on carbide tools as the clearance angles are so small.

John

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Edited By John W1 on 21/10/2015 10:16:49

Thread: Engineer's Blue
21/10/2015 09:59:22

As far as I know micrometer blue is an old style oil paint but may be ground more finely. I'd hazard a guess that it could be made by mixing oil paint with a grease such as vaseline.

A much older alternative that I have used is raddle. The name comes from rouge but it was made by mixing very finely ground red lead oxide with oil. If finely ground rouge is available it might be possible to make some. I doubt if that will be red lead oxide now. Actually raddle is much easier to use than blue. A thicker coating can be applied so there isn't any need to use such a thin coating of blue that it's hard to see it.

The easiest answer to marking out blue is to scribe a heavier line. This might still be a problem for older eyes. If a marker pen is used there is no need to cover everything with it - just where lines need to be scribed. No marking out blue when I did my apprenticeship. Some interesting tasks like filing to a scribed line but only reducing it's size by a factor of 2. Mostly on sheet metal work. It's possible to work to around 0.001in that way. Plenty of raddle as they also owned a battery factory so the lead oxide was easy to get.

John

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Thread: Groove for round belt pulleys
20/10/2015 22:42:36

I knew I had seen round grooved pulleys some where - HPC catalogue. Specially for polyurethane belting.

John

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Thread: Newbie with an old Boley lathe
20/10/2015 17:43:01

The only thing confusing about posting photo's on here is which albums icon to click. Use the green one and click create. Also use that one for anything you want to do with your photo's including adding more.

The other confusing thing is that the shot needs to be in the album before starting a post that you want to put it in.

When that's sorted out just click the camera icon on the post you are making and select the photo.

Or if somewhere on the web the one next to it in the same group and paste in a link.

John

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Edited By John W1 on 20/10/2015 17:44:02

Thread: Groove for round belt pulleys
20/10/2015 17:36:11

You can run then really tight Neal. That's why I think it's best to give them a miss, cause unless they are getting towards that they slip with very little load on them.

V belts tend to tighten with load but I do wonder if that happens on the miniature types.

John

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20/10/2015 15:27:07

I'd guess TC obtained his views from the English version. Neither are supposed to bottom but I find that hard to believe on the American one.

It also mentions that some think curved faces are undesirable.

Personally I feel for anything home made that could use a V belt the smaller width ones that SimplyBearings sell are preferable. There are also sewing machine belts of a similar design to these in polyurethane but the drive doesn't seem so strong and the top of the belts are noticeably wider than the top of the V.

John

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Edited By John W1 on 20/10/2015 15:27:50

20/10/2015 12:17:06

I think I'll just leave people to figure out what happens when these systems are used under load.

ropepulleys.jpg

I have seen something similar for leather belting but can't remember where. These are for manilla rope.

Anyway it would be tricky to work out on belts with different rates of compression with load but going on the above I would try the English one with no chance of it bottoming. On the other hand the belt coming out of the V may be "sticky"  of the angle is too acute.

John

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Edited By John W1 on 20/10/2015 12:19:41

20/10/2015 10:57:57

I have seen a round profile at the bottom of the V on older stuff but the modern belts are pretty compressible so it may be tricky to get it right. I think there is info in older copies of Machinery's.

As pressure on the belt needs to increase under load I think Tubal Cain's figures make sense. A more acute angle will help with that.

One thing I do know is that round belt into a old L1 (light 1) profile as on my Pultra is pretty useless for anything other than very light work on rather small diameters - what ever diameter goes into it.

John

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Thread: ER25 collet chucks that fit a myford spindle nose
20/10/2015 09:56:41
Posted by julian atkins on 20/10/2015 00:18:24:

as a fellow Dore Westbury owner and user, John's thread is of considerable interest to me especially as my Myford collets are all to imperial sizes.

i have a special head for the disposable carbide 1/4" dia shank cutters. i was lucky enough to get a further supply of these cutters at the Bristol ME exhibition last year.

cheers,

julian

I often use an ER16 2 morse collet holder on mine or 2 morse collets from arc euro. They do part sets for milling. The draw bar thread is too big for a DW so I either drill and fit a tapped sleeve to suit or add a short length of all thread with tapped hole to suit the DW draw bar. So far I have managed with the all thread. They are just loctited in place. I use the ER16 holder because it's easier to see what going on especially with small cutters.

I want to try a much larger cutter so am going to try ER25 and the myford fitting should be stronger than 2 morse plus less projection. I've no idea if the mill will handle a 100mm face mill. If not back on ebay and try another size.

The sort of fit that is needed is something of the order of 0 clearance to some 1/10 thou interference. The nearest standard I am aware of is ansi light interference fit number 1 but lathe registers are generally bang on size.

John

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19/10/2015 23:26:13

It might not go on Michael. I know from one of the suppliers that they did have some problems with them. That must have been several years ago. Be interesting to see if it's been improved.

Out of interest I do have an ML7 spindle from when I reconn'd one. The register is bang on 1.250" even via the vernier on the mic.

John

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