Member postings for Harold Hall 1

Edited By Katy Purvis on 01/06/2015 11:17:26

Having written for the magazine over many years I have found
it necessary to keep an index for the magazine, essentially 
for my own articles but have of course added them all. I 
have therefore thought that it may be of help to others and 
have added it onto the web, the address being
www.homews-mew-index.co.uk

Whilst it contains all the articles,  letters, trade items
and tips are not included, search facilities are also not
included except by using googles site search, assuming
google eventually searches the whole site, it runs to 60
pages. No additional programs are required. 

The index therefore only complements other indexes such as
that at www.cahw.co.uk

Its main strength is it is divided into 168 areas so that it
is possible to view all records on a given subject together,
ideal for the viewer who has an interest in a particular 
subject. 

Even so, if the issue of a known article is being sought, 
knowing the subject matter it should come up with the 
details required. 

Also, typically, where an article is explaining how to 
machine cast iron using a Vee block as the subject, it is
listed twice.

Harold Hall

I have just by chance come across Fred Townroe's original comments regarding my article on the filing machine. The situation is that all the drawings were provided and have been left out in error by the publishers.

I to was also unhappy with the publication of the series as I had asked for each sub assembly drawing to be published in the issue that the assembly was described, if this had been done it would have been more obvious that part drawings were missing. Unfortunately, the sub assembly drawings were published in the first issue separate from them being described.

It is a pity that Fred had not contacted the editor at the time, rather than commented about it in the forum, as the omission could have been corrected much earlier. I will now contact the editor who will decide how the error is best dealt with.

The brief answer to Goran's original question is Yes, I have, but looking at my name that should be obvious. Those who read my articles in MEW will have seen very many illustrations of it being used.

I do not though think mine is the be all and end all in QCTH design but as Bill Pudney comments it shows that there's more than one way to skin a cat!!

A few comments about the design may be of interest to those coming to this thread.

The original was developed to limit the amount of milling required firstly to minimise the time taken to make them and secondly making it practical for those who only have a lathe and drilling machine.

The time element should be obvious as drilling a hole through two holders clamped back to back will take no more than a few minutes, milling dovetails on two holders would take considerably more, perhaps a half an hour. If one intends to make a large number of holders that is a considerable saving. I would though recommend the hole to be reamed as drilled holes can be a little barrel shaped, though mine work adequately.

A technical aspect of the design is that the length to width ratio of the half round location is around 4 to 1 whilst most dovetail holders this will be around 1to1 maybe less. This should make it pull into place more precisely but there are other considerations. If you are unsure, consider a longish piece of 10mm diameter held in the three jaw to a depth of 10mm, then place it in 40mm, I know which will be running more accurately at its end.

Of course, with commercially made dovetail holders having a good finish, may be ground and hardened then they will move more freely over the two mating surfaces than ones made in the average home workshop. Of course if power feed to the milling machine table is available then it will be less of a problem but hand feed will cause furrows if the feed is slowed or even stopped.

It was also suggest that a square key to be used but the two curved surfaces coming together act as a mini inverted dovetail whereas the corners of a square would tend to dig in.

If I where making a set again with the experience gained I would just ream my drilled holes that make the locations and increase the throw of the clamping cam by just a little, though I think I have included this in the drawings on my web site.

I do not normally visit the forum, I do not have the time, but will keep my eye on this thread should any comments need answering.