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Member postings for fastdave

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

Thread: Basic threading
05/09/2020 10:38:07

After long hours, winding my self made mandrel handle on my new (old) Myford, I found that very light cuts were the answer to not breaking carbide tips, and made up a PTFE model - I cut the inner 18x 2.5 with three taps, then cut an outer 1" x 8 tpi, then parted offf, leaving a 6mm collar - worked a treat - now tramp on to 33 x 3.5 - cut the inner, started the outer thread, and half way through, stupidly realised I was cutting 30mm bar, as I had done for the 1 x 8tpi - Duhhh! But it's been a good learning curve for the Myford - amazing range of gearing with very different setups for the above threads. Thanks for all your help guys. ( and I don't think I'll be parting with the old Clarke 530 - it's a much heavier beast!

Dave, Fife.

18/08/2020 15:33:27

RDG woops - Oh, sorry, we have a 7/8 one as well - it might just be wrongly titled - we'll send you another, and check it's right before we do............I no stupid after all.........

18/08/2020 15:23:38

Thanks Andrew - I cut the thread into a 1" rod, which started as 1" - the backplate I ordered from RDG says 1" x 8tpi - am I being stupid - the max ID of the backplate is about 22 - not the inside on the threads - it's even smaller - I just need to know, and you are cementing my doubts that this is a 12 x 8tpi....

18/08/2020 14:49:54

I have just cut a 1" x 8tpi on the lathe, then pulled out the backplate it was to fit. nowhere near - I used 1" rod - the thread - no problem - the diameter of the backplate thread maximises about 22mm - does this mean a 1"x 8tpi is not 1" at all? - Help! What diameter should I be using - a table I looked at said 7/8. How?

Thread: Chucking out
31/07/2020 12:19:28

Thank you Hopper and JasonB, - run out at 4" = 0.14 mm -

the jaws on this one really don't need reground, and I sent the old chuck back to the seller.

The chuck is threaded, yes, and on a backplate, which I imagine just keeps the guts together - I did think about skimming the bush at the back of the thread, but the other chucks work.

I think I'll take comfort in Hopper's phrase about an old chuck - I'll keep it right with the tailstock.

Thanks guys - your usually helpful selves!

Dave, Fife, Scotland MM7ASN

31/07/2020 11:19:51

Hi folks,

I tried very hard to get to the bottom of a chuck wobble - I knew it wasn't seating, and pursued various efforts to grind the jaws, but the whole thing was badly worn - back to the guy who sold me the 1966 ML7 - another chuck at a price - Toolmex this time, not the original Pratt Burnard - but at least the jaws met, and it was in good condition.

I have to say that what made me certain the chuck was at fault, was the fact that I could true the same steel bar in the 6" 4 jaw chuck - all this with no tailstock support.

New chuck - at the jaws, pretty true - deflection at 4" out - wobble again.

Buy 2MT parallel bar - 11" long - also, since mouth of spindle looks pretty bashed, a 2MT reamer, and hey, RGD, I'll just have a 2MT tailstock spindle chuck adapter - extra check for the chuck - now wait

- Ahh, good, one day delivery - ream headstock spindle, insert parallel - and absolutely true - wind my way through all the tests I can muster - bur when I put the parallel in the wrong way round - into the chuck, - there's a wobble.

I now put the steel bar in, wobble still present - slide up the tailstock, dead centre - true as a die.

Am I being unreasonable in expecting this ole' ML7 to be true on a 4" 3 jaw chuck without support - I never had any of these problems on my old Clarke 430 - and it's not going anywhwere fast until my confidence in this increases.

Anyone got anything other than strong drink or vallium?

Thread: ML7 3jaw pratt burnard
20/07/2020 13:23:53

For me, Fascinating development of this thread. One can see why we would want to repair rather than replace, and I shall certainly be pushing on with lots of the above - one thing, though, no - one has suggested milling the jaws.....

Thank you all for great data,

Dave, Fife, MM7ASN (RSGB Callsign)

19/07/2020 18:33:00

Wow, you must be nimble fingered Alan - I'll have a go.


19/07/2020 18:07:08

OK, I think I'm getting the idea - the jaws are pushing against the sides of the holes.

I just made an attempt, encircling the middle of the jaws with a bronze ring which I knew to be round - and each cut seemed to do little, or make it worse - so I gave up and came back to the forum.

Now racking my brain to find something to use in trad spider form!

Ho do you align the dremel, or is the concentric motion the instrument fro self centring the grind?

Many thanks, Dave

19/07/2020 16:15:05

Thanks Ro, I had actually looked at this thread, and that made me think there might be a more precision way to true the chuck, but if it's a tried and tested method, I shall go for it.

Two things though, -

one - I don't have anything like the spider device which you display, Hopper, and I am a bit baffled, for if it is possible to overpush the jaws in one direction, how do we determine the precision of the other - not too sure I got my head around that one, although I can see how making them rigid works, what if they're rigid in the wrong direction, opposite to your criticism af holding the outside?

two - Is the dremel spinning? and if so - do we align it to one jaw before entry? or simply gauge it and run it through? - still sounds a bit iffy, or am I just overthinking this whole approach?

Many thanks for your thoughts,

Dave, Fife, MM7ASN

19/07/2020 11:52:04

Need a best as opposed to a best as for this one - help please.

I have even watched u tube on grinding out a bellmouthed chuck - I have one which is old and has seen some abuse, and grip is poor. To eliminate the bearings and the spindle, I plugged in the 6" 4 jaw chuck - and it turns beautifully and parallel - even looking at the jaws, they're in a poor state - so also are the outside set that came with it.

It just feels crude to insert a round grinder and spin the chuck, also someone suggested using a boring bar.

Both are within my scope, but I can't help but feel that some ingenious engineer is going to come up with a tried and tested method, or at least confirm the use of the above method/s.

Any takers?

Dave, Fife, MM7ASN

Thread: Message from the prime minister
17/07/2020 07:54:29

See- engineers do have a sense of humour!!!!

Thread: VFD/Lathe fault
09/07/2020 17:05:45

'have made installing smaller VFDs practical for folk with little specialist experience'

Don't mean to sound elitist, but that's why we have 'qualified' electricians. I went to work as a leader in a multi skilled taskforce for one of the Diagio outfits. I found quickly that electrical craftsmen moved quickly from one discipline to another, but mostly the mechanical guys had an inherent fear of what they couldn't see.

Healthy fear in my eyes - I have had brain jolting shocks, mostly from others carelessness, the worst being a factory foreman who came in and switched all of the machinery on to start the day, whilst I had a 'DO NOT TOUCH' notice pinned right in front of him - I got such a belt from 440V that I shouted out - very loud - involuntarily - yes, lucky me - I didn't die!

But let us not stop there, for have we not given the village idiot mobility, issuing driving licences willy nilly - most people could not tell you what the highway code is, never mind individual parking rules - but you're right, I digress - the point is that all of these devices have manuals with pages of health and safety and restrictions, before the technical stuff starts - electricity is not measured in thousandths of inches or millimetres - it is a silent invisible killer.

Dave, (I'm sorry to bring this up after such a happy ending), Fife.

09/07/2020 09:15:52

Brilliant - we all heave a sigh of relief - What a good end to a problematic week!

Dave, Fife.

08/07/2020 09:52:49

Ron, I've tried in the past, adjusting IF coils on a radio, to find I made things worse, and the fact was that no - one had adjusted them at all, it was much more basic - cost me an RF generator (costly item).

We may be barking up the wrong tree with the settings.

Dave, Fife.

08/07/2020 09:50:00

I'm with Dave on this one, really, but Let's localize the fault, to use one of the most worthwhile phrases in faultfinding.

Can you connect the motor straight into the VFD? It's just a matter of U,V and W connections from where they are just now, straight into the box - there are several ways of connecting, from terminal strip to ring terminals, but the essence is still U,V,W. - Since the VFD seems to run without the motor (I think I got that right), I am becoming very suspicious of the motor. Can you get to the terminals, disconnect and put an Ohmmeter across each winding? they should be about the same.

If you live near me, I'll do it for you - if you are not confident, grab an electrical pal who knows his stuff - if you solve it in the meantime, - Well done!.

Dave, Fife.

Thread: ML7 refurbishment
08/07/2020 09:38:05

Very interesting Dave - I tried all of these experiments before I re - read to find you said - DON'T - so insurance are coming back to me about smashed Window, dented mill, wrecked pillar drill, brickwork damaged, and I can't handle all of this from the ambulance - no idea what the lathe itself looks like! - (reaches for vallium and Vodka to intake Laphroiag from bottle!!!smile d

Seriously, being from an Electrical/ electronics background (Everything from TV experiments with MOD projects, to HV electrical, and after many apprenticeships, Gas, air and petrochemical A.P. (writing safety programs for all of these disciplines)) I have found, in the past twenty years, that Electrical people are not always the superior beings that they give themselves credit for.

If one reads from any of the Electrical regulations, 15th, 16th, 17th and so on - then pick up just about any article from MEW, the eloquence, precision and interest which is and remains with people from a mechanical background, becomes quite patent.

Yes, I fully acknowledge Logie Baird, Watt, Henry, Faraday, Tesla, Westinghouse, and many electrical geniuses I have met in my career, but I stand by that statement. I was disappointed in Electrical engineering - not Mechanical.

I am overwhelmed by you guys, electrical or otherwise, on these pages - no - one is supercilious, sarcastic, or smartassed - try the Linux forums, and you'll see what I mean!

Many thanks to all of you, oh, and Malc, I have that screw thread chart - I was looking for a photo of your gear arrangement - on my old clark machine, it gives a different set of gears for normal running aside from the screwcutting tables

Dave, Fife.

07/07/2020 08:38:28

Excellent! Thank you guys - Malc, could maybe use the picture, Dave - and before we get any comment, it applies to the old 56k connection on the internet - I got, I think it was T2 or T5 connection, which was actually 2 lines, and one could double up to get 128k if my memory serves me (and it usually doesn't) - in the olden days, this was lightning fast!!!

Dave, Fife.

06/07/2020 22:27:11

Much good data, won't need the photo Malc, that info is good,

Dave, you sound like me giving senior craftsmen, electrical and mechanical, a toolbox talk, and you're absolutely right - you musta been in H&S!

The others are right in their thinking, I do lose power with a 315 3 phase dual voltage, star connected - nice motor though, an Electramo - I've had it for years at the bottom of the bench - it was a spare wrongly diagnosed as bearing fail - I even bought spare bearings (SKF).

To put your mind at rest, I have always worked with precision instruments, am never heavy handed (sometimes to my detriment), and drive a 1991 Honda VFR like I drive my Honda CG125, proportionately that is. I had to reduce the 'jack the throttle and overtake that guy who just went passed' which I knew would eventually land me in the undertakers! in other words, I don't do speed any more, and although I am not a satanist, I understand too well what you mean, I was grinning away as I read your reprimand - if only everyone had that simple caution!!

I won't change it, and ordered two vfr's the other for my old Clark lathe - but that's another story,

Anybody need a perfectly healthy old AEI 240V 1/3 hp motor?

Maurice, Do I infer that it was the thread, rather than the smooth bore that was the problem, or was the thread on the backplate? The thread on the spindle nose is too big for a tap.

Thank you all - long live model engineers workshop!

Dave, Fife.

Thread: Oscilloscope kits - any recommendations?
06/07/2020 16:58:03

Go with the moderator mate, save yourself money and KMoon is incredibly clever - I have used several of their innovative devices - I have Hameg scope and all sorts of radio analysis equipment, but Kmoon takes value for money - I got one of these little scopes - way acurate enough by it's very nature, and a little signal generator (same people) - totally impressed - scope even comes with a probe!

Dave, Fife.

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