Member postings for David T

I was watching that same set of castings; nearly pulled the trigger but decided to follow Harold Hall's route instead........

Good afternoon All,

As mentioned in the thread title, this is NOT a question about screwcutting. I wonder how many people will miss that?

I'm not expecting a definitive answer from this thread, more just sharing my confuddlement. My Myford ML7 dates from around 1951. I have no reason to believe that my lathe is a "Frankenlathe"* assembled from donor parts. Recently I found that the mounting screw for the thread dial indicator is tapped M6, but I didn't think much about it at the time. Then last night I found that the mounting screw for the travelling steady is also M6, rather than the 1/4 BSF or BSW that I was expecting.

What is the reason for metric threads on a 1950s lathe? I appreciate that a damaged thread may be drilled out and re-tapped, but M6 is smaller than the 1/4" it should be. Can anyone offer an explanation?

Thanks!

* or more faithfully to Shelley's novel, Frankenstein's lathe

I'm not sure I understand the problem as I don't understand the link between dividing heads and screwcutting. However, if I may be so bold.......

Screw a suitably-sized wooden dowel into the hole. When the dowel is withdrawn it will hopefully have the mysterious thread cut into it. This will give you an approximation of the "male" thread required. Use this to take your TPI and OD measurements, perhaps subtracting a few thou from the OD to allow for clearance. If the thread still doesn't conform to a known standard thread, then make a new screw on the lathe to match the dowel.

At first glance I read this as two additional people literally climbing out of the rucksacks in comical fashion. I imagined it as some kind of scheme to circumvent the admission fee. When I re-read the post I was quite disappointed

Only if viewed from above

Mike, that's very tidy. Are you using the mounting hole for the travelling steady? Sorry but I may just have to copy that.

This was a very popular technique back before hobby milling machines became common. It still is very common amongst the clock makers, especially for wheel (gear) cutting. If you look in the old books (Sparey, Westbury etc) you'll see many examples of how a milling spindle can be used to great effect; the only difference being that they generally used a stand-alone motor for power (battery drills weren't invented yet!)

I believe there was an American(?) design of woodworking vice that used an interrupted screw as a quick-release mechanism.

My vernier height gauge only goes down to 1.5". I use 1-2-3 blocks to the raise the work up off the surface plate then add 1" to the height gauge setting.

Yes, that would be an appropriate question! I confess that I typed my opening post in haste and probably missed some important points.

As of late my need for dividing has been limited to small scale PCD stuff. It was easily accomplished on the BCA, but it did mean having to remove the item from the lathe chuck and re-centering on the rotary table. Not a game-stopper, but not ideal. I also had to cut the stock shorter than I'd like in order to fit it under the BCA's spindle. A dividing head on the lathe cross slide would solve both issues. I expect more PCD work in the future, and quite possibly small wheel and pinion cutting. Any milling "around a corner" I think would be best accomplished on the BCA's rotary table.

Cost isn't a huge problem but naturally I don't want to spend more than necessary. I don't have much stock lying about so I'll have to buy in everything needed to make a HH head. It's still cheaper than the GHT kit but not by much, so it's not a deciding factor.

That Emco head is elegant in its simplicity and would do nicely, but I suspect it's availability and cost will put below the other options.

Edited By David T on 26/07/2018 16:27:12

Thank you all for your replies, they are much appreciated.

Emgee - Yes I expect you are right, they probably are too tall for the BCA. More than likely I'll be using the dividing head on the lathe. I can (and have!) used the rotary table for dividing, but as you say there's always the "other" plane.

Thor - Yes, I never thought of lowering the centre height. Maybe make a riser block for use on the lathe in order to match the lathe's centre height?

Mick Henshall - Thank you for the photos. I find it interesting that the dividing head is clamped to the bed, but still appears to be at centre height with your engraving tool (which also appears to be the HH design). Does that mean that your dividing head sits above the spindle height if used on the crosslide?

Bazyle - As I have an ML7, the GHT castings are at the correct centre height anyway. So from that perspective there's no difference to the HH design. I quite agree on matching the nose to my lathe, I have no reason not to.

Phil P - I remember seeing your Sigma(?) and your dividing head on that "other" forum.... Very nicely done!

Ian T - I've seen someone else post up their Timmins, it looks like it fits the bill. I couldn't find much information on that website though?

One other thing, and again this is probably just me being dense..... The basic GHT kit from Hemingway comes with just a 24T wheel for simple indexing. I appreciate that 24T provides many of the common divisions, but it appears that any other number of divisions requires the full index plate + worm arrangement. Is that correct? The HH design, on the other hand, allows the index wheel (gear) to be easily swapped as required.

Afternoon all,

I'm sure this must have asked dozens of times but strangely I haven't found a direct answer. I must be searching the wrong terms....

I want to make an indexing / dividing head, suitable for my ML7 and BCA mill. The options I'm looking at are the simple Harold Hall design, or the GHT design sold by Hemingway in kit form. Are there any particular reasons to choose one over the other?

Thanks

Being heavier is not always an advantage. I brought my ML7 home in the back of a Clio, then manhandled it through the garden into the shed with SWMBO's assistance. I'm not sure how practical that would have been with a Colchester, not to say I wouldn't want one.....

There is an ongoing discussion about this on the ukworkshop forum. Members are being encouraged to contact their MP (I admit I have yet to do so).

https://www.ukworkshop.co.uk/forums/topic112718.html

That's a nice looking handle. I made mine from the Hemingway kit, I wonder how I ever got on without it.

Now that's a clever idea...

I'm sad enough that that made me chuckle

Edited By David T on 06/07/2018 16:31:21

Not all tailstocks are created equal; the standard Myford ML4 tailstock had a through-hole, but mine was solid and self-ejecting. I rather prefer the knock-out hole as winding the tailstock all the back was quite tedious.

An ML2 has a centre height of 3-1/8", an ML4 is 3-1/2". If I recall correctly, the recommended size motor is 1/3hp to 1/2hp.

Edited to add: The usual advice is that if you need to buy a new motor, it may be beneficial to buy a 3-phase motor + VFD. 

Edited By David T on 02/07/2018 14:32:31

My workshop is screened by trees to the south and is easily the coolest place on our property. It does get rather cold in winter though. SWMBO's wood turning / carving shed is in the direct sun and is like a kiln. As part of a garden remodel we shall be replacing that shed, and we're strongly contemplating a "green roof" for whatever replaces it.

How about boring a short length of stock, concentric to the OD, to be a close fit over the threaded portion. Then run the fixed steady on that? (Similar in principle to a cat head, for those who are familiar)