Member postings for Harold Hall 1

It depend Rod how basic you want you information. However, there are four basic articles on my website being, Direct Current, Alternating Current, Electronics and Electrical motors. You will find the four listed on my website index here.

Harold

I am in the process of adding videos to my website with the purpose of bringing to a wider audience the workshop projects that appear to be overlooked. In contact with another workshop owner very recently I commented, that whilst typically my Grinding Rest and Basic Dividing Head were being made in quite large numbers but for my QCTH I only knew of a very small number being made, he being one of them. He pointed out, something that I had not considered, that the grinding rest and dividing head appeared in my books giving them a very wide audience.

Even so, my QCTH often gets a mention on the numerous forums but is bypassed in preference to a commercial product.

Another reason why my QCTH not being taken up is that the design is often misunderstood, typically, that it uses a round post into a half round channel which it most certainly is not. For this reason, the first part of the video is devoted to explaining how the design was developed and how it works.

Another section shows how the half round channel is produced by drilling and reaming a hole on the join between two holders held back to back, being very much quicker and easier than removing a lot of metal if going down the dovetail route.

Another section, for me at least, is the most satisfying as it shows how accurate the system is. I have taken multiple measurements for both the vertical (height) and horizontal plains, taking them at 50mm from the end of the holder to exaggerate any error.

Vertically, the result was much better than 0.01mm (0.0004&rdquo with the horizontal test not being quite a good but still within 0.01mm. My contact mentioned above had also carried out tests with very similar results.

I realise that most on the forum will already have QCTH's but would appreciate it if at least some could give the video a viewing. Thanks in advance.

The Video can be accessed via my website here, click on video, top left.

Incidentally, I have 22 videos prepared but will only publish details on this forum of the few of particular interest. I have also one produced for my grinding rest showing the setups for sharpening a lathe knife tool, with the intention of creating others for endmills (both end and side), slitting saws, dovetail cutters, boring tools, drills four facet, etc.

Harold

Thanks Norman

I agree Richard, T slots are much easier to use than plain slots. When I devised my "alternative to a four jaw chuck. **LINK** using a T slotted base. I realised when complete that I now also had a T slotted face plate, so much easier to use in most cases than conventional faceplates. Also, being heavier, easier to balance.

Harold

I have made the CES tilting angle plate but as is almost always the case with commercial angle plates, fixed and tilting, the provision for securing workpieces on it was limited. three slots in this case. Fortunately, the casting was very substantial and thick enough to include tee slots. So in addition to the three vertical slots I added three horizontal tee slots.

See my efforts here here

Harold

My one and only clock was to a design by John Parslow being publishe in the ME magazine starting in issue 4322 and was in around six alternate issues. If you are interested then it can be seen here .

Harold

Thanks Andrew, that is very interesting. From my tables 3.4mm drill results in a 70% depth thread and 3.5mm very close to 60%, so with 3.6mm I would assume around 50%. Could you give us an approximate idea as to the depth of thread. This leading to the advice to those unsure, that one should err on a smaller drill for threads that are less in length than the threads diameter. Even here I would not go for more than 80%, normally no more than 70%.

On a general point regarding published information, it has always concerned me, coming from a non metalworking environment, how information is listed as exact. The drill for this thread IS "ab", the speed for machining 20mm diameter mild steel IS "cdef" and yes I have seen tables listing speeds to four significant figures. For me it is a case of , the drill for this thread CAN BE "ab", see notes at the end of the table.

Harold

Thanks Neil for your comments regarding Tubal Cain's value for 8BA but unfortunately I did not make my comments clear. Rather than talking about actual values I was commenting on his general principle to use drill sizes larger than were quoted in most tables and that 60 to 70% thread depth was adequate for most situations, even quoting less than 60% for some.

When I was producing my "Metalworkers Data Book" I calculated the drill sizes myself on that basis for all the common, and less common, threads.

On a wider range of data, I found a number of errors in Tubal Cain's "Model Engineer's Handbook" as I did in other publications, even British Standards. Unfortunately, in the attempt to get the project finished, as it had become very time consuming, I did not make a note of the errors found.

Harold

I agree with JS 3.3mm or 3.4, even 3.4 gives 70% thread which is plenty for all but the most arduous situation. I also agree with his suggestion for using roll thread taps. For metric threads I hardly ever use anything else. No swarf left in the tapped hole and the screws just float in. You do of course need to use larger drills, even here I tend to go up one size in some cases.

Since I took note of Tubal Cain's (not the Youtube variety) suggestions on drill sizes for tapping holes I have never broken a tap.

Harold

Sorry Rik, I should have done this in my earlier post.

Thanks for the complementary comments regarding my grinding rest design and web site and for adding the links to it.

By the way, how's the glass cabinet going.

Harold

Well done Rik you really have made a fine job of it. Are you going to make a glass cabinet for it? I have seen many versions of my rest some made from aluminium because their mini milling machines were not up to the task for some of the machining. Another gave the rest a galvanised finish.

Just one point about the calibrations on the operating knobs these are purely to enable the user to put on very small amounts, say 1/2 to 1 thou, with confidence as that is about as much as should be ground of at a time. With the knobs being so beautifully finished you won't even see them turning. just joking.

Harold

If only!

Thanks Kwil

Harold

Ady. Following your prompt regarding me adding a link to this forum on my website I have now done that. As I said, I would then feel I should also add links to the many forum that I make occasional comments on and whose members publish links to my website within their comments.

I had though the number of forum was 15 but getting out my list and comparing it with the stats for January I found a few more and the list actually is now 30 forum. No doubt it will grow as I will check the stats for the next few months.

I contribute to most of the English speaking forum but only very occasionally. I have also contributed to a couple of the non English forum using Google translate, (hilarious results with some languages) and reply in English asking that someone would translate it for the local language, has worked on the few occasions I have tried

The list can be found on my website here

Harold

Tim

Have a look on my website at the lathe back stop here and open up the drawings listed on the last page. Forget all the rest but view parts 3, 5 and 6.

Now consider parts 5 and 6 being placed into the end of the mandrel bore and secured by part 3. This is the result of part 6 expanding part 5.

We now have a fixture in the mandrel with a hole through it that could take the draw bar. If a handle or nut is placed on the thread on the draw bar and at the outer end of 3 it could be used to close the collet in the normal way,

On opening the collet the draw bar will start to move out of the collet and therefore out of the assembly.

If now the draw bar had a suitably placed collar on it towards the collet end it would eventually contact parts 5 and 6 stopping the bar coming out further, as a result starting to eject the collet.

I see no reason why this would not work on the majority of lathes but whether it is worth making the parts as, as some say, a light tap on the bar will extract the collet if not over tightened.

Harold

John

I accept your edit and feel a link to my website for details of the book plus a link to My Hobby Store for purchasing it would have been the correct way to go.

However, in this case, to my surprise, and no doubt yours John, My Hobby Store do not list the book, actually only listing 2 of my books.

If you are interested in the book Nick you will find it widely available on the Internet.

Harold

If I may be allowed, once more, to publicise one of my books, you may find my book "Dividing" of help Nick. This covers amongst other things, the mathematics of using a dividing head/rotary table but also lists all the available divisions using the hole numbers in common division plates, and for wormwheel ratio's of 40:1 60:1 and 90:1 . For more details regarding the book, see http://www.myhobbystore.co.uk/search.asp?k=harold+Hall&x=23&y=2 here.

It also includes simple methods of achieving low number divisions and more complex methods for higher numbers.

Ady, if you remember, last time I mentioned my books, or was it a page on my website, you prompted me to add a link on it back to this forum, I have not forgotten. However, with there being at least 15 forums that I visit, and wanting to make a good job of the task it I am finding it difficult to find the time. I do though still intend to do it.

Harold

Edited By John Stevenson on 16/01/2016 16:32:11

I was thinking along the lines that Steve and Mike suggest but see they have beaten me to it. However, the link Mike gives for Hemingway kits has heavy duty alloy castings for the faceplates so the machining process will be a little different, but of course the set ups will be the same which is the main purpose of the exercise.

Another possibility is that Hemingway's Quick set face plate also includes an angle plate using an iron casting so this is much the same as the College eng, one but a little smaller. Perhaps Hemingway would be prepared to supply you just the angle plate, worth a try.

Details for machining this faceplate, and the angle plate. is covered on my website here , machining the angle plate being much like the process I describe in the book.

Harold

Thanks Ady for the prompt, in fact I do do as you suggest for personnel websites similar to mine. I did also have a link to the ME/MEW website on my home page. Initially, I only intended my website to be a show case for my many pastimes, this can be seen by the fact that pastimes such as live sound recording, cabinet making, pencil sketching, etc. have all low page numbers. Similarly, for personnel pages such as our holidays and being members of the Salvation Army.

However, as most readers will know, the website has grown well beyond those initial ideas and the home page has been edited on numerous occasions with the link to the ME/MEW site going AWOL. I will therefore Ady again add a link to the forum. I feel though that having done that I have a responsibility of doing it for the other forums I am a member. My present list has fifteen forums on it and I know there are others that link to my website, some non English speaking. So as they link to my site then I will place a link to there's. I can create the list from the data I receive for visits to my website.

As this will no doubt increase the list to twenty, plus, I feel a page dedicated to the links would be the best approach. As I am very busy at the moment (hence the delay in replying to you comment Ady) I cannot promise to do this till the new year but once done I will come back to let the thread know.

As an aside, the link I see from a forum in many cases gives a link back to the actual page on which the link to my site exists. This is good as I can see immediately the subject being discussed. This site though, with a few others, lists the link as coming from the home page. Because of this I have to use Google to see what is being discussed relative to me.

Harold

If I may be allowed to publicise two of my books which are intended to introduce the newcomer to the lathe and the milling machine. These, have both plans and instructions for making workshop equipment, and progressing from the very simple to relatively complex items, in so doing moving the novice from beginner to quite able machine user.

The books are, “Lathework, a Complete Course” and “Milling, a Complete Course”.

See my website here and here for details.

If you wish to take up Neil's suggestion of a H10 or V10 Stuart engine and would like to make a quick start then you could take a look at my pages regarding making these. They are though based on using a lathe only but most of the milling task methods can easily be transferred to the milling machine. The article can be found here. Other wise follow David's thread as it progresses.

As a relatively newcomer to metalworking you may fine my website as a whole worth looking at, it has around 500 pages of metalworking info. The best place to start is at the book style index. With individual questions you cannot do better than to pose them on this forum, the members are very helpful.

Harold

Used on a surface plate in an inspection department for checking a dimension on a number of identical parts, note the small lever on the top for raising the plunger making it easy to place the component for checking.

Harold

Thanks John, Richard and Mick

Chris, You could also consider my off hand grinder attachment here

This only sharpens the end cutting edges but in most cases it can considerably improve the cutters performance. Personally, I think it could give the EMG-12 a run for its money, but I may be biassed.

For my Sharpening book and the Milling milling book, both of which have details of the more able grinding rests, see here and here

Harold

Edited By Harold Hall 1 on 18/10/2015 16:55:56