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Member postings for John Haine

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

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Thread: Which milling vice
05/09/2010 18:35:54
Here's a suggestion - buy some good angle plates and make/buy some clamping kit, and some 123 blocks.  Though I bought one of the common 4 inch swivelling machine vices when I got my VMB, I actually use it much less than other forms of clamping.  In particular I've got a "webless" angle plate, ground all over, I got for a song off a market stall, which has also got a fence bolted on one end - gets used all the time.  Quite to fit to the mill, true it up with a square rather than having to dial it in, dead accurate, doesn't suffer jaw lift, can hold quite big chunks compared to the vice.
Thread: Magnetic Milling Machine
26/08/2010 10:16:55
I had exactly this problem with my Myford VMB.  It seemed that the quill and to some extent some cutters had become magnetised.  I made a demagnetiser which is a bobbin using a short length of plastic drainpipe big enough to accomodate the end of the quill, about 5 cm long, end cheeks made of thin plywood, wound with about 500 grams of 23 gauge enamelled copper wire (a complete spool bought from RS Components).  This is fed from the mains through a 100W lightbulb to limit current and also provide a tapered "inrush"current - when the mains is switched on the current is very high becasue bulb is cold but it dies away as the bulb heats up.
 
Technique is to sit the bobbin on the mill tableon steel packing with a slug of mild steel in it (because the quill won't touch the table at extreme downfeed).  Bring the quill to press on the slug, switch on, then slowly raise the quill out of the magnetic field.  One application fixed the problem and I've never had to repeat it.  Glad to supply photos of how it was done - depending on your location could loan the kit (assuming it would fit your quill).
 
John.
Thread: How to accurately bore a milling spindle on an old lathe
13/08/2010 17:47:30
Another way to do this is to make a double-ended MT2 arbor - ie 2 make tapers back-to-back (assuming your lathe h/s is MT2 as well). It may be possible to do this by joining two off-the-shelf MT2 arbor blanks, but I made mine from scratch.  You first chuck some 3/4 free-cutting and turn the best MT2 taper you can; then remove it from the chuck, remove the chuck, and mount the workpiece in the h/s socket by the taper, holding it with a drawbar.  Now turn the second taper MT2 and also drill and tap for a drawbar.
 
Then bore an MT2 hole in the spindle stock material and ream it to size/finish.  You then fit the double-ended arbor in the h/s, and mount your blank spindle on the end sticking out, hold it by a drawbar (ie.a bolt) and turn the outside to be concentric with the MT2 socket you just made. Sounds long-winded but it didn't take me too long and it all worked.  If I can find it I could lend you the double-ended arbor I made?
 
John.
Thread: Myford alternative
30/07/2010 21:29:12
I've got an S7 and it turns stainless without sweat,  even big stuff, just use carbide tool, keep the speed down and take sensible cuts.
Thread: Book on Clocks
19/07/2010 09:57:54
It isn't a how-to book, but the title that got me interested in horology and tells you most of what you will ever need to know about how clocks work is "My Own Right Time" by Philip Woodward.  I have had my copy for well over 10 years and still am getting more out of it.
Thread: Adjustable v-ledges
14/07/2010 10:13:16
Fixed part of the slide has the dovetail where the gib strip goes not parallel to the other side of the dovetail, by an angle that equals the taper of the gib strip.  Then by adjusting the logitudinal position of the strip you take up clearance.
Thread: Need for recomandations on cut off or parting tool
11/07/2010 09:27:32
Q cut is good.  Best IMHO is the rear cutoff tool designed for Myford and sold through Kirjeng.  Regularly use this as explained by GHT parting off under power feed, never had a problem.  Not sure if it could be adapted for the C6.
 
 John
Thread: Lathe Drive Motors, 1ph or 3ph?
05/07/2010 08:35:12
Norman, was it Power Twist belting that you bought please?
 
- John
Thread: Highly sought-after Aciera F1 and Sixis mini-mill
21/06/2010 17:56:23
If tensioned at highest position to balance weight, will be over-compensated at lower position, maybe likely to make mill more likely to snatch when plunging a drill or mill?
 
Thread: Converting S7 pxf to CNC
20/06/2010 20:20:53
I'd mentioned before that I had converted my S7 lathe to CNC, inspired by the series on converting an ML7 in MEW.  As someone was asking for details I have now taken some photos and written a bit of explanatory text for them, which I'd like to put on the site if anyone is interested.  This would  need the ability to add files which has been mentioned in another thread - any chance of this please, moderator?
 
John.
Thread: G-Code in a downloadable form
20/06/2010 10:08:03
Extending this suggestion (an excellent one by the way), as there is already a facility to upload jpg files, why not simply allow all file types and also allow anyone to upload files such as g-code or dxf as well as the webmaster to post files associated with articles?
 
I for example have a simple Excel spreadsheet for calculating belt lengths and pulley spacings for toothed belt drives.  Would be happy to add this.
 
Most other machining forums (e.g. Yahoo!) allow this.
 
John.

Thread: Highly sought-after Aciera F1 and Sixis mini-mill
19/06/2010 19:28:43
An alternative is a Spiroflex extension spring -
 
These are used in things like modern sash windows and for closing sliding vehicle doors.  I have yet to get the company to reply to my enquiry!  
 
I used to own an F1 which I inherited from my father (he bought it from his company when they closed down - they made electron microscopes), with quite a lot of accessories.  Beautiful machine (though leadscrews very worn), but much too small for model engineering.  I got a good price for it and bought a Myford mill.
 
John.
Thread: Lathe Drive Motors, 1ph or 3ph?
30/04/2010 15:05:07
Can anyone recommend a supply for the Fenner drive belts for the S7 please?
 
John.

Thread: Single Phase motor speed control
29/04/2010 20:18:57
That sounds a good idea.  I did find some Scott transformers on the internet - made in India and look like they weighed a couple of tons!
28/04/2010 13:29:59
Update - see Wikipedia
 
 
This says that actually the windings are identical so the motor should be balanced.
 
The transformer is called a "Scott Connected Transformer" =
 
 
...and it might be possible to buy them as a standard item?
28/04/2010 13:19:57
An interesting question.  In theory a capacitor start and run (CSR) motor is a 2-phase machine, where the quadrature drive for one phase is derived through the capacitor.  You can derive a 2-phase supply from a 3-phase one using an appropriate pair of transformers, so it ought to be possible to run a 2-phase motor from a 3-phase VFD.  Two problems in practice - the VFD output won't be very sinusoidal so the transformers might not work very well, and the CSR motor won't be very well balanced as the winding the capacitor supplies only has to generate enough flux to get the motor started (I think). 
Thread: Stepper Motor General/Basic Question
25/04/2010 19:55:29
If you want to run the motor fast but for an exact number of steps then you need to be careful about how it is accelerated and decelerated.  I remember being at Leeds University where a lot of the basic work on stepper motors was  done (see the classic textbook by Acarnley) - every day one would hear wailing like a WWII siren as motors were run up to high speed then down again to stop at an exact position.  The pulse frequency profile to do this is not trivial and you would be better using a computer to generate it I suspect.
Thread: Does Anyone offer a Lathe Add-on CNC Kits?
19/04/2010 21:49:37
I have converted my S7 (later PXF model) and it was fairly straightforward.  I followed basically the methods in the MEW articles last year by Tony Jeffree but with slightly different and simpler mechanics.  Closely followed his electronics (though that's my profession) and had no problems.  I'm hoping to write up what I did as a couple of people have expressed interest.  Used Mach3 as the controller.  A few teething problems but pretty successful overall.
 
John
Thread: The story behind logging in...
19/04/2010 08:31:25
Sometimes what you copy and paste gets a spurious space inserted as it is sent to you.  Then the system thinks that what you have pasted as a password has an extra character and doesn't recognise it.  If using the copy/paste method (which I do all the time) always check that what is pasted has the same number of characters as you can see on screen before you copy.
Thread: Milling Machine
09/04/2010 21:16:46
Get the biggest mill you can afford/fit in and not a lathe accessory.
<< First < Prev 269 270 271 272 273 274 275 276 277 278 279 Next > Last >>
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