Here is a list of all the postings Eugene has made in our forums. Click on a thread name to jump to the thread.
|Thread: What did you do Today 2018|
Murray, I don't know if you've seen the "floor tile levelling clips' that are now available, they make to job so much easier it's untrue. Google Ebay and / or Screwfix. You just ease the tile up or down a bit using a wedge arrangement and when the adhesive has set, break them out.
Edited By Eugene on 18/02/2018 20:17:46
|Thread: Myford M type half nut Thread form?|
That's pretty much the technique Geoff outlined in his article, as developed by Steve Papworth.
Looking at my bobbin, if I bored out the old threads, there would be precious little left, if anything. I'll have to do some carful measuring, but the Mk.1 eyeball says it won't do. For that reason Geoff made a complete new arm.
Probably the pre war Drummond machines had a lot more meat in the sandwich than post war 1946 Myfords have.
That's really helpful, thank you.
Thanks for the offer of help, I may well take you up. There are any number of projects in view at the moment, so it doesn't matter if this goes on the back burner.
Before today all I knew of the half nut was that the backlash was around .080" I took the assembly off today and had a closer look; official verdict is a severe case of cream crackeredness, I bet close to half the thread thickness has gone.
As you warned in your article, there is very little meat in the "bobbin", so it looks like a new bracket / assembly of some kind. The leadscrew itself looks to be in fine fettle.
Hopper, thanks for your input. When you say "modified arm" did you attach the bobbin to the existing arm in some way? Geoff went the whole hog and fabricated a new arm that had an adjustable interface for the bobbins' final fit. Looking at it this morning I thought it would save a bit of time to use the existing arm, nor would it be too difficult to build in a bit of adjustment.
Onwards and upwards,
Edited By Eugene on 14/02/2018 15:55:30
Thanks to all.
I spent six hours driving up and down the M6 today, so I had plenty of "creative thinking time" available.
The thing got a bit more clear in my mind, and you've confirmed what I worked out. Grinding the tool still bothers me a bit, but there is another project in view that requires a straight thread, only an external one this time; I can play around with that first and get a feel for the job.
Dave, I've seen the softened acetal method described before, but didn't fancy it somehow; can't really say why, perhaps it's not "authentic" enough, but thanks for the link anyway.
Brian, the man who never made a mistake never made anything. I find this a great comfort shortly before the hammer hits the thumb.
Lads and Lasses,
I'm looking to repair a worn leadscrew half nut on a late model Myford M type, probably following one of the methods published by Geoff Walker.
This requires making a new half nut in phosphor bronze; although I'm not very experienced in screw cutting I think I've got the basics on how to do this, but there is I think, a problem.
I'd assumed the 3/4" x 8tpi leadscrew thread to be an Acme type, but looking at it, I don't think it is, there seems to be no flank angle at all, just a plain square thread. That implies no commercially available thread cutting insert, at least I don't see any, so I'll probably be making my own. That doesn't fill me with much confidence, my tool grinding skills are pretty rudimentary, and this cutter needs to be very accurate.
Guessing, grinding a suitable HSS thread cutter is just a matter of making up something like the business end of a parting off tool of appropriate width (whatever that is) and cutting to the appropriate depth (whatever that is) at the appropriate helix angle (whatever that is).
So what thread form is it? Anyone have accurate dimensions of the original factory issue? Given that I'd much prefer to buy a thread cutting tool rather than try to bodge one, is anything available? Am I missing something?
Thanks in advance,
Edited By Eugene on 13/02/2018 09:26:10
|Thread: Bench Grinder advice|
In particular i have been looking at the record range.
Probably the best you can do is just look. My experience with a Chinese made Record grinder was pretty dismal.
Horribly out of balance, very poorly machined spindle, flimsy light that fell off, an all round dog. I chucked in the skip after putting a hammer to it to prevent some innocent skip diver from demolishing himself.
Arc Eurotrade sell their "Allwin" 6" and 8" bench grinders for a bit more money than the Records, but they are much superior. I use a 6" in conjunction with Harold's simple grinding jig and find it a great combination.
I've also had a second hand Warco 8"... very sturdy and smooth machine, but a bit of a lump for what I wanted.
I wouldn't use any grinder that wobbled at working speed, the potential for a catastrophic accident just isn't worth it. If your Clarke does so I'd either sort it or bin it.
|Thread: What did you do Today 2018|
Managed to fit the motor / countershaft assembly to one of my M type lathes after the move from Wales.
That 70 year old, half horse Higgs motor is a bear of a thing. Very heavy, very big, unbalanced, and not a symmetrical surface or hand hold on it. An absolute pain in the hacienda to conjure into position when you're on your Tod. What we used to call "a right trusser". Shifting the lathe body onto the stand was a doddle in comparison.
Does anyone have a grasp of the total weight of a standard M Type, plus cast iron stand plus the motor and countershaft? Felt like a block of flats when I tried to shift the whole issue; I fitted some heavy duty castors which solved the problem, but without them I'd be lumbered. Or lumbagoed, one of the three.
Edited By Eugene on 05/02/2018 23:58:46
|Thread: replacement for Dewhurst switch|
I'm just wiring up one of those Chester switches. The wiring as supplied is as shown in Jon's pic, (minus the terminal block) but in the latest iteration the wires are not all black. The mains input wires are the short black pair attached to terminals 6 and 8.
Be aware that throughout this switch, contrary to domestic wiring convention a red wire does not indicate "live" nor does black indicate "neutral".
The pair of red wires coming from the centre terminals of the rocker switch are one set (i.e. one is live and one is neutral) and are used on one of the two windings on the motor. Similarly the black wires coming out of terminals 7 and 5 are another set for the second winding.
I've used coloured tape to identify the various polarities as in the pic below.
This is the rear of the rocker switch showing the pair of red leads that feed one of the windings on the motor.
To check which of these is the live or neutral, I first wired terminals 5 and 7 (the black pair) to a lamp. With your live mains input attached to terminal 8, terminal 7 is your live to the lamp. The lamp lit when I switched on. Then I removed the neutral and substituted on of the red leads. It didn't light up, so it must have been another live feed. Changed it for the other red, the lamp lit so I'd positively identified the neutral.
It all sounds complicated but when you study the switch unit it's pretty simple.
Two other things I'm going to do is make much better provision for earthing than the old Dewhurst did: there was no earth to the motor casing at all, just to the switch body, plus add in an emergency stop button.
Tried to embed the pics but the album function wasn't having it.
Hope this helps, Eug
Edited By Eugene on 05/02/2018 23:24:53
Edited By Eugene on 05/02/2018 23:29:52
|Thread: Bench Grinder|
Once again Arc Eurotrade is your friend.
The Allwin 6" comes at a reasonable price, is well made and doesn't wobble all over the place. The rests are no much better than any others (they are however adjustable) so I made Harold's simple grinding rest and haven't looked back. Usual encomiums ...
|Thread: UK Men's Shed of the Year 2017|
Just over a year ago we moved from the Welsh hills to near Ludlow in Shropshire to be a bit closer to civilisation as we are both around 70. The Welsh Health Service wasn't scoring big points.
I also made the decision to withdraw from the world of gun dogs and gundog training which is the pivot around which our social life has revolved for thirty years. I don't want the responsibility of looking after dogs any more; if we see an ad in winter for "cheapie three weeks in Spain, loading on Thursday" we want to be able to go, and you can't easily do that with six dogs in the kennels.
All of which means that whilst not exactly feeling lonely, I could manage the company of some other old farts interested in producing things like swarf and shavings. Ady's post prompted me to look up the local Shed movement and hey presto one is in the making just over the hill in Cleobury Mortimer. I'm going up to meet t'lads on the 11th of Jan for a progress report, pint and a natter.
So thanks Ady, good on you for jogging my elbow.
Edited By Eugene on 27/12/2017 10:53:51
Edited By Eugene on 27/12/2017 10:57:04
|Thread: Rust removal methods safe for cutting tools / precision parts?|
A warm solution of boric acid powder / crystals is a cheap and very effective rust remover.
It really penetrates the rust deposit and is safe to use. I've used it on cast iron plane bodies very successfully. The only drawback is the danger of after rusting; best to water rinse, WD40 spray big time, and then use a spray oil.
There is a potential for hydrogen embrittlement on hardened parts with the electrolytic method, but wether it actually occurs is moot. I spent a long time studying the phenomenon and knew no more at the finish than I did at the start; an unpredictable business.
|Thread: Funny Old World....|
What a snip.
The Starrett level alone is worth the dosh you paid. Keep the Myford slide (or flog it) then weigh the rest in with the tat man and your'e in an "obscene profit situation"! If thet old Grayson does clean up, someone will have a bit of fun learning how to use it. Well done you.
I think the least you can do is buy the dog a couple of cans of Butchers Tripe!
|Thread: Will I ever need a reversing switch?|
What is wrong with Dewhurst switches?
My first lathe, also an M type, had a Dewhurst fitted, and nothing else. So there was no NVR facility which I now regard as fundamentally unsafe; so too did the late Sir John of Blldgeport. Using it I managed to brush my hip against the lever and start the motor as I was attempting to change speed by shifting the Vee belt. Thus my body was against the revolving chuck and I had my hand on the belt. Not a comforting thing to experience.
And don't believe a chuck won't unscrew itself; I've had it happen. Circumstances .... big face plate on the spindle with an end mill in the spindle MT1 taper. I was using the face plate simply to ensure that parts held in the milling slide were square on, there was no work or tooling attached to it.
Inadvertently through tiredness or inattention I selected "Rev" rather than "Fwd" ; the face plate promptly unscrewed itself and dropped onto the end mill, so it didn't fly off the machine, but the cast iron thread was demolished, and the plate rendered useless. Fair to say I was running at warp factor 10 to get the mill closer to it's proper cutting speed.
Sir John would no doubt have applied the epithet "Clumsy bastard" and he'd have been right, but I was a very raw hand then and knew jack.
I see the metric thread point now, I didn't before, We need to keep the gear train together to ensure the thread geometry stays put, (the thread indicator dial being of no use) but the tumble reverse negates that. So the need is to reverse the whole shooting match, not merely the chuck ..... got it.
I think I'll fit a reversing switch, just in case I ever do need it, but not that cursed Dewhurst thing! Once bitten and all that. Something like the Crompton in John Swift's reply looks to be the thing.
Like I said, it's a beginners question, thanks for the help and input.
Edited By Eugene on 19/11/2017 21:26:44
Lads and lasses, beginners question ....
I'm refurbishing a Myford M type lathe and I'm now at he point of fitting a new motor and it's associated switch gear. Given that the spindle is threaded and so chucks can only work safely in one direction, what use is the normally fitted reversing switch? (These are traditionally the Dewhurst type but I won't have owt to do with them.)
I have a tumble reversing gear, so the lead screw rotation can be changed at will.
So, what use a reversing switch to me? Isn't just wiring the motor through a simple NVR switch enough?
|Thread: English dialect|
"On the scunt" was common enough usage in the factories around Smethwick when I was a young man.
In similar vein we had "rough as a bear's a**e", and "sticking out like a bulldog's b******s". An easy sliding fit was "Like the skin orf a donkey's d**k".
I did say we were common!
Edited By Eugene on 17/09/2017 11:53:02
|Thread: Aircraft General Discussion|
Cader is on "The Mach Loop" a designated low flying area. "Mach" isn't a reference to speed, just a shortened version of Machynlleth, the nearest town.
Enthusiasts park themselves on the mountain and make videos to post on Youtube as per .... https://www.youtube.com/watch?v=rB4HVn6Rnmk I tried to embed it, but it didn't want to play ball.
Just to one side of the lake is the Tyn y Cornel hotel; many a time had a lunch there watching the show. About half an hour from home when we lived in Wales.
Edited By Eugene on 30/08/2017 10:37:36
|Thread: Bending and welding acrylic sheet?|
No, but smoking in the presence of chlorine-containing vapours is not conducive to long life and happiness.
How true. I've seen the result, hence the precaution.
Just to add ..... when the maintenance / fabrication guys made a few smaller barrels (hexagonal I think about 9 inches across flats), they used a home made strip heater something similar to the one John described.
However instead of a fixed bed one side was hinged; all they did was just lift that side, hold it steady at the required angle and switch off the heat. There are DIY versions described on YouTube.
From memory the edges were then held together with a big, cemented, exterior lap joint using another bit of angled Perspex strip.
Edited By Eugene on 12/08/2017 20:28:27
Mike posted, "I've always understood that perspex can be solvent welded with chloroform."
Indeed it can. I used to make up 5 litre batches of such cement in the lab. for making Perspex plating barrels. These get a tremendous physical battering, but I can't remember a joint failing in normal use. The construction was all lap and housing joints.
The method was to heat the chloroform up in a large glass beaker and dissolve powdered perspex in it.
Can't remember the quantities off hand, but I always made sure the fume cupboard was working before I started the job, and got the cigarette smokers out of the way!
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