Drive Dogs etc

[VicParticipant @vic]

Before the invention of the scroll chuck, when stock was held with a drive dog, how did they accurately make the holes in the ends of the bar for the live and dead centres? Anyone know. Just being nosey!

[VicParticipant @vic]

[Martin KyteParticipant @martinkyte99762]

Are we assuming no 4Jaw chucks too? in which case clock true and drill.

Other wise.

Marking out, dot punching and Drill press maybe.

regards Martin

[JasonBModerator @jasonb]

Possibly started with oversize stock so it did not matter if ctr holes were a bit off as once mounted between ctrs and turned it would become true.

[BazyleParticipant @bazyle]

Also perhaps more items were started from black bar so needed turning to size anyway.

[Martin ConnellyParticipant @martinconnelly55370]

It would not surprise me to find that in a busy shop there was a dedicated role of drilling out centres for the turners. You could set up a drill with suitable kit just for this job and pay someone a lower rate than the fully trained turners. Keep the expensive workers doing the thing they are good at rather than the low skilled jobs of selecting and cutting off stock to size and centre drilling the ends close enough to the centre.

Martin C

[egaParticipant @ega]

Posted by Martin Kyte on 20/12/2022 12:28:04:…dot punching…

And possibly with the use of a bell punch.

[Bill Davies 2Participant @billdavies2]

Lathe Work for Beginners (Yates, 1922) shows a bell centre punch, and a centre drill with a tailstock (presumably Morse) taper.

After finding the centres (e.g., using calipers or a bell punch) and punching the centres at each end, the work would be supported on the headstock 'live' centre, and a centre drill mounted in the tailstock and drilled in the usual way, then reversed and the second hole drilled. I have seen this another book, which I can't locate at the moment.

[Martin ConnellyParticipant @martinconnelly55370]

Bill, your book extract says use a chuck in the headstock to drill the workpiece. The OP asked what was done before chucks were readily available.

Martin C

[Bill Davies 2Participant @billdavies2]

I agree, Martin. My text suggests the earlier method of finding the centre by whatever means (calipes, odd-legs, bell centre) then using a centre punch, followed by centre drilling. The centre punch was the original method of producing the centre holes, hence the 60 degree angle often mentioned, whereas the prick punch was a finer angle to pick up scribed lines. The key point was that the centre drill was held by machine taper in the tailstock, and temprarily supported by the headstock centre whilst drilling.

My memory suggests (reliably?) that I saw a similar setup (in yet another old book) on a pedestal for centre drilling.

Older books mention "Slocombe" for centre drill, but I have only seen this name mentioned, no image of it. I suppose it was the original manufacturer.

Slocombe drill

Bill

[DC31kParticipant @dc31k]

Posted by Martin Connelly on 20/12/2022 16:03:48:

The OP asked what was done before chucks were readily available.

The OP asked about chucks to hold the stock.

I am quite sure you can think of a way to hold a drill bit in the headstock without using a chuck if you put your mind to it (hint, look at Fig. 78 of the same book).

[Martin ConnellyParticipant @martinconnelly55370]

DC31k, the question is regarding work holding for drilling when you don't have a scroll chuck not drill holding.

Martin C

[Bill Davies 2Participant @billdavies2]

In my reading, Vic's post refers to making centre holes for the purpose of driving using lathe dogs, predating the use of scroll chucks. Martin Kyte mentions four jaw chucks in passing, and also the drill press.

Going down the rabbit hole (and attempting to answer my own comment about Slocombe drills), US patent US2481939A (applied for 1945, awarded 1949) shows a modern style centre drill. US Patent 505,013 (1895) mentions a spade-type drill (and also a twist drill or straight fluted drill) to form the centre.

So I might presume that up to that time, some craftsmen might make their own flat centre drill. In the 70's I made a flat drill from a forged end on 1/4" silver steel, turned and filed the end, then hardened and tempered. About 3/8" diameter, I was surprised how well it cut into solid steel without a pilot hole. Most of us are happy to grind our HSS to suitable shapes, such a centre drill is little more work. And if we don't have 'sharp' centres in our lathes, we wouldn't need the little hole for clearance of the point. OK, a pocket for oil, grease or (remember this) tallow.

Bill

[VicParticipant @vic]

Posted by DC31k on 20/12/2022 16:22:23:

The OP asked about chucks to hold the stock.

No I didn’t.

Thanks Bill. Your Bell Chuck suggestion sounds good to me!

[Grizzly bearParticipant @grizzlybear]

I have found Huskies are very good. ( Drive dogs).

Bear…………….

[bernard towersParticipant @bernardtowers37738]

Is it possible that this predates the slocombe drill and spade bits would have been used?

[Dave HalfordParticipant @davehalford22513]

Before scroll chucks I would imagine a cup with 3 or 4 bolts in it to drive the work for drilling the first centre.

There was a humungus 4 to 5 foot faceplate lathe in the old B'ham science museum on Newhall St that 90 angle brackets with bolts to hold the work.

 

PS I like Huskies too, but I can't manage a whole one.

Edited By Dave Halford on 20/12/2022 17:59:15

[Bill Davies 2Participant @billdavies2]

Dave, I think you (or they) have invented the independent (and often) 4 jaw chuck!

Bill

[Dave HalfordParticipant @davehalford22513]

Posted by Bill Davies 2 on 20/12/2022 18:22:35:

Dave, I think you (or they) have invented the independent (and often) 4 jaw chuck!

Bill

So much simpler though.

[DC31kParticipant @dc31k]

Has no-one ever turned up a new handle for a wood chisel?

You centre punch both ends of the handle. Then take the hitting end of the handle, locate that end in a dead centre held in the tailstock and with a drill bit in the headstock (which could be a centre drill bit on a Morse taper, as shown in Fig. 78 of the book above) drill the hole in the end for the tang. Your left hand holds the chisel handle and stops it rotating and your right hand winds the tailstock handwheel.

What works with wood will also work with metal. No chucks were used in the making of this post.

[duncan webster 1Participant @duncanwebster1]

I'm surprised no-one has mentioned a bar square for marking the centre. I have both one like the link and a smaller fixed version. Very useful

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Duncan, I have used one of those "bar square" items quite often, but a vastly better quality one than the one in your link.

As far as bell punches are concerned, I've only ever used one once, and that was in metalwork class at school, but can't remember what we were making for the need to use it.

Regards Nick.

[not done it yetParticipant @notdoneityet]

They may not have had modern chucks like we do nowadays, but I expect they had face plates which could be ‘adjusted to grip/hold material for drilling the ends with their Slocombe centre drills.

Edited By not done it yet on 20/12/2022 21:37:02

[Clive FosterParticipant @clivefoster55965]

The simple centre square **LINK**

https://www.toolbank.com/0/p/FAICSQUARE38

pre-dates the combination square with V stock like that linked to by Duncan. I imagine that would have been a common way for craftsmen to locate teh centre of a round bar for puching to make a drill starter hole. Back in the day a combination square set would have been seriously expensive. Few ordinary workers could have afforded their own.

I've had mine for 50 years and use it so rarely I've almost forgotten I have it. More likely to grab the Starrett combination set I scrimped & scraped up the price for second and 40 odd years back.

Clive

[BazyleParticipant @bazyle]

If you have nice clean round stock a carpentry marking gauge, which most old timers probably would have made for themselves, quickly scribes a square or triangle on the end to guide a centre punch.

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