Member postings for derek hall 1

Some years ago I made the "basic" knurling tool from Hemingway Tools and I use it with straight knurls as I prefer that to diamond. This tool was easy to make and use, gives great results and is a very worthwhile addition to my workshop.

Regards

Derek

Hi, on my Emco FB2, the drawbar has an M10 thread on it.

But I agree with Nigel B's comments - not advised to resort to a hammer and drift.

I wonder if the MT chuck you have fitted has a 3/8th BSF or BSW thread - guess it depends on how old it is

Regards

Derek

I would rather not get into the debate about which is better the graduate engineer or time served, but I recall a phrase a long retired work colleague who was an ex chief petty officer with 22 years with the navy. He said....

"Someone with a degree is someone who can work out the square root of a jar of pickles but can't take the lid off"

Made me laugh then and still does!

Derek

Apprentice time served ONC/HNC I went to local tech colleges when they existed - otherwise known as the "The Toothickfor University"

The thought of going back to fiddling with shims to get a tool up on centre height....urgh! backward step in my opinion.

QCTP works for me if you use it correctly.

Maybe for interrupted cuts or taking large cuts then you may have problems but +1 for the gibraltar tool post, use that instead for these occasions.

I agree though with John Baron above though but again it depends on what you are doing with the lathe...

Regards to all

Derek

Regarding statistics........BAH....maths for politicians !

Only got to look at the farce that is Covid stats, differs country to country, no real definitions of terms and as usual anyone can do what they like with stats to get the results they want.

I studied some maths stats with the OU and found it very interesting how the data can be manipulated.

Anyway sorry to go off topic...

I worked in Sewage Treatment for Anglian Water several years ago - when I tell people this everyone says it sounds awful, helped by experience of dropping a bolt in the raw untreated incoming sewage and putting my hand in and pulling out something that commonly occurs in sewage instead!

Point I am making that the job was reasonably well paid but not many wants to work with waste water so should I have been paid double for working in sewage?

Off topic I know, but I always wondered about when and why that connection between average salary x 3 = what you could have has a mortgage was done away with. It was the link between affordable houses but now its virtually impossible for first time buyers, especially in Cambridge.

Regards

Derek

We have a fair number of assemblers building fairly complex electro-mechanical equipment and they do a 40 hour week for about £12 an hour.

Most of the work looks (and is) repetitive and tedious, however most are happy with working 10 hours a day Monday to Thursday and having every Friday off. They say they go in auto mode and other than chatting to each other during work, most of them are not seeking more challenging or responsible jobs even when it is offered.

Horses for courses I guess.

Regards

Derek

Yep, the website opens ok for me as well...and I see the collets advert.

Hi everyone,

As the person who started this thread I am been following the comment with interest and thanks again for all of your input.

I "think" we have at the answer to the question!

But here is another question, what about the material of the cotters?. I have always made them from brass to lock onto steel shafts, but Hemingways mention the cotters should be made of steel for the Quorn, as steel is more effective at locking. While this maybe true I will probably make mine out of brass for my Quorn as I have not had any issues with brass cotters and steel shafts on other equipment...

Regards

Derek

Hi everyone, thanks for your input !

I was just wondering if there was a "sweet spot" in the centre to centre dimension (i.e. offset) or if there was some optimum offset between the bore and the split collet

I have just spent 30 mins looking at my GHT books building the universal pillar tool and building his dividing head as there are copious amounts of these split collets on his designs.

In the Hemingways instruction in building the Quorn the offset is given by:-

D = bore being clamped, d = the diameter of the clamping bolt that sqeezes the two collets together (NOT the diameter of the collets as I presumed it to be)

D/2 + d/2 + 0.02" = the centre to centre dimension for the split collet and bore.

Now I checked this with the GHT articles on his kit and his offset is 0.01" larger than suggested by Hemingway, that is:

GHT method is:- D/2 + d/2 + 0.03 = the centre to centre dimension of the clamping bolt and bore.

So both methods seems to suggest that an offset anywhere between 0.02" and 0.03" is the optimum

Without boring you too much more, GHT does say that "while the clamping effect is very powerful, the 2 halves of the collet may not separate when the clamping pressure is removed. This is down to one or both of these reasons (a) the offset between the bore and the clamping bolt is too large and (b) the shortening of the back of one of the collets was insufficient".

In addition GHT mentions that this offset is important and is recommended that it is held to within 15 thou (0.015"

Well I have lots of these to do on my Quorn so I feel confident that this offset works without stuffing up any castings!

Thanks again for your time and of the jigs and your suggestions. Just got to get prepped for all those ball handles next !!!

Kind regards

Derek

Thanks for all the great replies everyone, maybe its not a critical as I thought!

What a font of knowledge this forum has...!

Regards

Derek

Hi, I have previously built the GHT Pillar Tool and his dividing head, both using the split cotter method to clamp shafts or spindles with good results.

I am now building a Quorn and I am going to use the same method rather than slitting the castings and using a pinch bolt.

In all cases that I have examined the calculation of the "correct" offset distance between the centre lines of the shaft/spindle (to be locked) and the clamping bolt are different. This is not only for GHT's tooling but the Quorn.

In the Hemmingway drawings for the Quorn, it indicates that the "overlap" or offset to create the clamping effect from the cotters is half the diameter of the bar + half the dia of the clamp bolt + 0.02" (thou).

George Thomas' calcs are slightly different and he explains why this overlap when using split cotters is fairly critical due to the clamping effect and self release when the clamp is slackened off

So is there any guidance on best practice on this?

Incidently GHT used brass cotters against steel spindles, Hemmingways say better efficient clamping is obtained with steel cotters against steel spindles...

Looking forward to some enlightening replies !

Regards to all

Derek

I fitted the Hemingway upgrade to the leadscrew dial on my Myford S7 some years ago. It's an easy and useful upgrade but I find the resetting pinch screw always seems to end up in the opposite side to the user I.e. in the most inaccessible position!

Regards

Derek

Wow that's a mighty machine. You must have a huge workshop !

I used something like this in the shipyard during my apprenticeship, it looked a heavy beast, top heavy and must have been awkward to move.

The fitters shop was on the first floor where the radial drills where, when the yard closed in the 1980's all the machinery was auctioned off.....so it most have been possible to move it, dont ask me how though I had left by then.

Good luck!

Good video....and no annoying background music!

Regards

Derek

+ 1 for CUP Alloys. I agree with all the other companies mentioned so far, can I recommend Power Tools Direct who sell amongst other things genuine "Python" wooden file handles at reasonable cost.

In addition M Machine metals, Hemmingway Tools and Westfield Fasteners esp for stainless steel cap hd, grub screws, buts and washer of all sizes.

I agree with Bill D, we are fortunate indeed to have the support and expertise of suppliers for our needs.

Regards to all

Derek

After many years of using a very basic tailstock die holder, I decided to get the imperial and metric set as per Jason's link. Recommend....a great piece of kit in a purpose made wooden box.

Yes I could have made something similar but with so many projects to make on my list and so little time......

Regards to all

Derek

Easiest and quickest way for the UK to save energy is to turn off alternate floors of office lights.

London city for example with its towering office blocks lit up like a xmas tree for most of the night probably most of them empty as the occupants have either gone home after their days work or are now working from home....

Those that work nights simply "hot desk" to a floor that is lit.....

Regards

Derek

Great post Dave and all true.

I work for a UK company but now owned by a faceless American consortium, their mantra is profit first quality of product a distant second.

Some of our equipment is manufactured in China, but the Chinese wages are increasing, the Chinese worker wants western luxuries, colour TV, car etc, and it is increasingly there is a shift for many Western manufacturers who use China as a cheap place to make their "stuff", to relocate to other countries such as Vietnam and Indonesia.....and even back here to the UK...

Yes I know it's not a model engineering topic but it does sort of affect where we buy "our" stuff from..

Regards

Derek

I suppose if you buy a mill/drill machine you can do both!

I have an Emco mill and very rarely use it for actual drilling, I would not want to be without my 40 year old sealey 1/2 inch 5 speed pillar drill.

But horses for courses.

If space is tight then you obviously need to assess what sort of work will you be doing and what machines give you the flexibility to do that.

Regards

Derek