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Member postings for Peter G. Shaw

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

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Thread: Making a screwcutting tap
19/02/2010 21:46:05
Hi folks,
A recent project with my grandson resulted in an attempt to make a UNF 3/8 24tpi tap out of silver steel. Lots of things went wrong but we did eventually manage to cut a thread in a piece of aluminium. This is what we did, along with what we know we did wrong, but I'd like to ask, for the future that is, for any other thoughts.

I should point out that one of the reasons for this project was to let the grandson do as much as possible, and to see the rest.

First we took a piece of half-inch silver steel and turned it down to 3/8ths. Unfortunately the only way that we seem to be able to get a smooth, and hence accurately measureable, surface is to rough turn first, then finish turn using high speed and slowest possible manual feed. So of course, the finished surface ended up slightly less than it should have been, and a repeat attempt the same. As it happens, the device that was intended to screw in was itself slightly less, so we continued.

Next we screwcut. In retrospect we should have produced the taper first, so that was yet another mistake. Anyway, I've never had much luck with trying to calculate depths of cut etc for screwcutting and so had to resort to using a nut as a test piece. So this is what we did, and produced a thread.

At this point we tapered the job. That was ok, we used 8° included as per Tubal Cain's instructions.

Then we tried to create a cutting edge using a minidrill with a grinding disc in the chuck. We had looked at other similar sized taps and realized that we needed to produce an undercut under the cutting edge and so we tried to set the minidrill appropriately. We weren't particularly successful and finished up using a file to try to improve matters. Thoughts on how to do this would be most appreciated. Also on how to produce, say, three cutting edges.

Having got this far we then hardened it. Ok we didn't bother with the one hour per inch as per Tubal Cain and others, but neverthe less got it very hot and then quickly dunked it in cold water. This was followed by tempering to light straw, although here again I suspect we may have heated it too quick and possibly had some of it nearer brown.

We tried it out on a piece of aluminium, slowly increasing the drill size until we could get it to cut, which it did after a fashion. After cleaning up, we found that the original device it was meant for could actually be screwed in, albeit tightly, so in that respect it was more or less successful.

Grandson, by the way, was absolutely delighted with the result, even though it wasn't perfect. To him, it was the act of screwcutting in the lathe and then hardening and tempering the silver steel, none of which he has ever seen before.

So, thoughts please.

Peter G. Shaw
Thread: Simpler the Better -what do you use?
19/02/2010 19:55:08
In DesignCad, one has to choose either a "normal" straight line which can then be at any angle or an "ortho" mode which forces the line to be either vertical or horizontal depending on which way it is drawn. I don't recall it disabling any of the snap commands.
 
Why would one do it? Because, certainly in my drawings, there are a lot of lines drawn either vertical or horizontal and it is far easier than attempting to do the same using the other line drawing command. One can, of course, use absolute, relative or indeed polar co-ordinates as necessary to do the same. Often I find that I need to draw a temporary line from say the elevation to a side view to ensure that the two drawings are lined up correctly. To do this I first draw line B at roughly 90° to the proposed line A and somewhere past where it is expected to go, then draw line A from the originating point to line B using snaps for the start and finish. This then tells me where the side view should be and I can then draw as necessary. Once the side view is started, I can delete both the temporary lines, both of which were drawn and used without any need for accurate measurement.
 
Regards,
 
Peter G. Shaw
Thread: Blown X1 Mill speed control
07/02/2010 19:58:31
Hi,
 
Somewhere I read that Machine Mart, who supply a lot of Clarke stuff, have a very good spares parts catalogue. Perhaps that could be a good place to try.
 
A few thoughts are that the maximum working voltage of the device isn't high enough. Again I believe I read something about this in conjunction with Arc Euro Trade and the X2 series mills. Perhaps there's another avenue to explore.
 
Also, what about the power handling capacity?
 
Regards,
 
Peter
Thread: Gib lapping article
25/01/2010 16:38:13
Try MEW 146.
 
If you haven't got the mag, & no means of getting it, I could scan and email to you.
 
Regards,
 
Peter G. Shaw
Thread: Tongue in cheek
25/01/2010 16:22:22
The late Tubal Cain/T. D. Walshaw, in an article in ME (23 May 1997) said that in Europe at one time, the "foot" varied between 9½ and nearly 19 English inches! Also that in France, there were 8 different "feet"!
 
(I always knew that bit of useless information would come in handy someday.)

Regards,
 
Peter G. Shaw
Thread: Belt drive for mini mill / x2 sieg arc
20/01/2010 17:07:26
Hi,
 
If this turns out to be a duplicate posting, please accept apologies - not sure where the original went.
 
I'm not sure what you mean by "the third main gear in the head." Do you mean the third set of gears on the intermediate shaft and the mandrel? Because if you do, then Arc Euro Trade do sell metal replacement gears.  (Look under one of the lathe spare parts, C3 I think.) 
 
Like you I have broken these gears, and have put replacement plastic ones in, but this was before I discovered the metal gears. I have bought the metal gears ready for next time, and as far as I can tell they are exact duplicates.
 
Peter G. Shaw
Thread: Tachometer design
17/01/2010 16:03:14
Hi folks,
 
Recently I used a cycle speedo from Halfords to measure the rpm of both my lathe and mill.
 
There were problems, eg fastening the magnet onto the rotating shaft, above 30kph (equivalent to 300rpm) it only measured every 5rpm, and above 60kph (I think) it only measured every 10rpm whilst above another speed it became intermittent.
 
Calibration involved setting the device to kph and setting it up as if it was measuring the speed of a particular sized wheel (1777 was the value I used I think). With these values it gave direct rpm readings.
 
Changing the wheel size value means that the device can be used for different rpm ranges, but then it will involve some calulations.
 
On the plus side, the device was readily available (removed from the bike to have a new battery fitted!), and reasonably easy to use. And it met my requirements.
 
Regards,
 
Peter G. Shaw
Thread: Mystery Steady
09/12/2009 22:09:53
Don't know what it is, but it's given me ideas for a fixed steady for my lathe.
 
Many thanks,
 
Peter G. Shaw
Thread: Seeking article on Bench Drill upgrade
29/11/2009 21:40:08
Ooh, I've gone over all funny like!
 
Seriously though, glad to have been of help. And yes, I have aften found that another mind can think of a different way around the problem.
 
Regards,
 
Peter G. Shaw

29/11/2009 14:52:44
Hi Edward,
 
These articles may contain the info you want. I have not looked at the articles them selves, but simply referred to my homeproduced database. They seem to refer to quill backlash elimination.
 
ME 19 May 89 page 621 & 05 Jan 90 page 51
MEW40  Jan 97 page 20
 
These articles refer to modifying a drill press into a cheap milling machine, hence may also help.
 
MEW33  Jan 96 page 12
MEW35  May 96 page 66
MEW92  Aug 03 page 52
 
Hope this helps.
 
Peter G. Shaw
Thread: true Space
21/11/2009 19:55:32
This appears to be the thing with TurboCad in that it IS very difficult to get started with, indeed, certainly a few years ago they were giving V.4 away free so that people could learn on it before committing themselves. Later, I noticed that they have a so-called Learning Edition which seemed to be a cut-down version of V4 (which itself was pretty dreadful!)..
 
The idea of setting up Layers first is always a good idea. I use:
 
1 Outline
2 Centre Lines
3 Hidden Details
4 Dimensions
5 Drawing Text
6 Title Box
7 - 10 Construct 1 - 4
 
I often find that I need to use some temporary lines in order to draw other lines. These lines are not required in the final drawing and can be deleted when no longer required. This is the purpose of the Construct lines.
 
Any complex program will require a lot of study and learning (trial & error?) before one can get the best out of it, but it is my belief that some programs are easier than others in this respect. For me TurboCad fails completely in this respect, whereas Design Cad does not.
 
FWIW, the most complex drawing I have done with Design Cad was to draw a gear wheel complete with involute sides to the gear teeth (albeit with a slight modification as per Ivan Law's book Gears & Gearcutting). I have also set up an animation showing how a spur gear meshed with an internal gear.
 
Regards,
 
Peter G. Shaw 
Thread: Which Cutter Grinder?
21/11/2009 19:40:26
Hi Ray,
 
First of all, an apology. Contrary to what I said, WSP 39  does NOT have anything in with regard to grinding rests.  I have absolutely no idea why I mentioned it. Please, please accept my apologies.
 
Secondly, the two rests described in WSP 35 & WSP 38 do indeed appear to be different. 38 is describes by HH as "A Simple Grinding Rest", but it does have accessories for endmills, square & round workpiece holders, slitting saw sharpening, etc. There are also other tool sharpening devices. FWIW, the No. 38 rest seems to use a ball around which the rest is swiveled to obtain the various angles, whereas No. 35 seems to use a combination of slides/dovetails and swinging arms.
 
Hope this helps, and once again, sorry for the duff info.
 
Regards,
 
Peter.
 
ps As it happens, I have bought every one of the WSP books, and have found the vast majority of interest. Certainly I have absolutely no hesitation in recommending the HH books, along with those by Tubal Cain.
 

Thread: Can't find what I'm looking for!
20/11/2009 19:49:26
First of all, the gib strips I have seen have all been the same design, ie a rectangular bar with chamfers on two diagonally opposite corners. I'm saying this to be absolutely certain of what we are talking about. In addition, the adjustment screws all seem to bear on a "hole" partially drilled in said strip.
 
Now, on one machine, possibly the Hobbymat but can't be sure, there was a transverse diagonal groove into which one of the adjustment screws located. Also, I had a suspicion that the Myfords used the same idea.
 
On my present machine, the dimples for the screws are rough, dead rough. And I'm not too sure how accurately located they are in respect of the position of the adjustment screws, which themselves are Allen head grubscrew types with a squared off end . The gib strip itself is somewhat rough. So the intention is to replace both the gib strip and the screws with better fitting items. And this where the idea of the transverse slot or groove comes in. Incidently, although there is a locking screw, it does not have anything to locate in.
 
Reading Circlips message above, I'm now thinking I may have misunderstood the purpose of the slot or groove in that it seems that it may be a device to assist in locking of the slide. This does make more sense to me because on the one I remember, there was just the one groove, but I can't remember whether it was for locking or not. It would make sense for it to be locking because the groove would make a weaker point which would then bend easier.
 
 Your comment on the ball bearing size does make a lot of sense since the original article I read used a 2mm diam ball, whereas my slides use 6mm screws, hence I would have thought that perhaps a 4 or even 5 mm diameter ball would have been better. 
 
 I don't have a ball ended cutter so would have to make do with a drill point. Mind you, I could write off a drill bit and round it off!
 
Ok, I think that initially reassembly with existing items is on the cards, followed by replacement with better stuff.
 
Regards,
 
Peter
19/11/2009 22:06:39
Hi all,
 
I'm in the process of  re-building my Warco MiniMill (at long last - don't ask!) and am trying to add some improvements as I go along.
 
One such improvement is to clean up the dovetails as per David White with his X1 mill - and by heck they need doing. Eg, the visible slides of the column were reasonably, but the invisible slides on the matching part looked as if they had been roughly ground down with an angle grinder. Anyway, next step is to add some more gib adjusting screws, a new gib strip, and some small balls between the screws and the gib strip.
 
Now, Circlip recommends a slot in the gib strip. But I think that somewhere I've seen something about using a V shaped slot as done on the Myfords which perhaps seems rather better than Circlips presumably rectangular slot. But can I find it? Can I heck!
 
I've been back as far as MEW 138 (Feb 2008) looking in Scribe a Line. I've scoured any thread that might seem appropriate on these forums, nothing doing. So does anyone have any idea about this? Is my memory correct? Or is it a figment of my imagination? If the latter, then fair enough, I won't object if someone tells me that, but please, someone put my mind at rest.
 
Regards,
 
Peter G. Shaw
Thread: Which Cutter Grinder?
19/11/2009 15:36:59
I wouldn't have described Harold Hall's jigs as jigs. Indeed Hall himself describes them as Grinding Rests for use with a D/E grinder. They do include adaptors to enable the sharpening of milling cutters.

It all depends what you want to do. If you want a kit of parts, then you will have to buy, eg the Worden, but if you wish to make from stock materials, then Hall is the way to go.(And possibly cheaper as well.) Workshop Practice Books 35 (Milling A Complete Course), 38 (Tool and Cutter Sharpening) and 39 (Model Engineer's Workshop Projects) refer.
 
 Regards,
 
Peter G. Shaw

Thread: true Space
19/11/2009 15:27:04
My only experience of pencil drafting was in the craftwork classes at school a good ½ century ago.
 
Then, about 15 years ago, I needed to draw some plans for the local council so settled on Draft Choice for Windows. This was an easy to use and understand shareware 2D CAD program which happened to have an excellent (for me) manual which gave an excellent introduction to CAD. Unfortunately, with improving computers, the program became more and more unreliable, hence was scrapped.
 
Tried TurboCad, and found it very difficult to use after DraftChoice, so eventually plumped for DesignCad. This program is a 2D/3D program and for me, was very similar to Draft Choice hence the changeover was quite easy. Design Cad, if you can find it (not easy because it is now owned by IMSI who also own TurboCad which IMSI seem to push in preference to DesignCad) can be found at about £25 for a reasonably up to date version.
 
Design Cad encourages drawing at full size, with scaling to fit the paper being applied at printing time. Whilst Absolute drawing is easily available, I find it much easier to use a combination of Relative drawing coupled with snapping (a method of, eg, selecting the end of an existing line to start another line).
 
One thing I like about CAD is the ability to experiment, or design if you like, on the screen without having to waste reams of paper, and whilst for something simple such as a rectangular bar with a slot in it, CAD is well OTT, designing something more complex is a lot easier with CAD.
 
So, to return to the original posting, I doubt very much that I will be using trueSpace (and anyway, it's now been discontinued by Microsoft who own it) especially as I already have a CAD program with animated 3D facilities - if indeed I do need that facility.
 
Regards,
 
Peter G. Shaw
 
Thread: Cutting male threads
13/11/2009 20:55:41
re Tubal Cain's model Engineers Handbook & thread data.
 
There is a useful book by Tubal Cain in the Workshop Practice Series. No. 12, Drills Taps & Dies which covers a lot of useful stuff about threading.
 
Regards,
 
Peter G. Shaw
Thread: Metric vs Imperial - Practical or Traditional?
11/11/2009 13:01:50
I too was brought up on imperial. Indeed when studying Telecomms Principles we were still using cgs units which eventually became mks.
 
For myself, I decided one year that a kitchen cabinet I was making would be done completely in metric - which was how I changed over as it were. Later, I bought an imperial micrometer (for use on a Maxi engine). Then later again when I got involved in engineering I decided that I would only use metric equipment.
 
Ok, I do have imperial drills, but have decided to go totally metric so as they break/wear out, they will not be replaced.
 
These days, I now automatically think mostly in metric, but can still use imperial - indeed, if measuring something I use whichever system has the nearest graduation mark.
 
Like other people, I don't see it as a problem, after all conversion is easy. What I would suggest though, is that anyone starting from new in this hobby possibly needs to consider going totally metric as certainly in the UK, everything else is slowly going that way.
 
Finally, a comical story.
 
About 15 years ago I wanted to build a porch and so I contacted the local planning department. Very helpful except And she kept saying it. Fair enough, I was quite happy and it was easy for me to do.
 
Then, one day, whilst discussing something, it happened!
 
LP: "Of course, we're not really bothered about the odd inch or two."
Bit of quiet, then-
ME: "Er, excuse me. What are these inches you have just mentioned?"
Dead Silence, then I slowly burst out laughing.
 
After that, we got on just fine.
 
Regards,
 
Peter G. Shaw
Thread: Overheating grinder
08/11/2009 11:20:26
Hi everyone,
 
Thanks for all the comments. Obviously more research and thinking by me required.
 
Regards,
 
Peter
06/11/2009 22:08:16
Meyrick,
 
I do have a single point presumably diamond dresser and had been thinking about using it, but have also been wondering about how much I would need to take off to regain the sharpish corners. Certainly on the coarse wheel it would be quite a lot, say 3 mm. The fine one wouldn't be as much, but due to drill sharpening using a Picador drill sharpening jig (there are others around very similar) the side of the fine wheel must be slightly concave. As a result, I've been considering changing the wheels anyway.
 
Two thoughts are some sort of cup wheel (I think that's what they are called) and/or trying to use 6" wheels rather than the 5" as standard, but this size may put too much load on the motor. Any thoughts?
 
Also wondering about going diamond.

Regards,
 
Peter
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