How was it done before CNC

[Alfie PeacockParticipant @alfiepeacock58331]

I have a very good understanding with engineering as I use to be a sheetmetal worker in the 70s. My question which has occurred from using my mill and lathe at home is how did production using milling machines work before the cnc and tape.. With the lathe a capstan and automatics were about for years, but how was production done with milling machines, I remember Briidport, Adcock Shipley, type manual mills but they can only do one offs or small batch, and it must of been hard work in those days before DROs arrived on mills.

[Alfie PeacockParticipant @alfiepeacock58331]

[Jeff DaymanParticipant @jeffdayman43397]

Try googling "hydraulic duplicator milling machines". These were used from the 1950's I believe. I saw a row of one type in the 1980's in a plant in New York state that had four spindles coupled to the duplicator so it made 4 parts at once. There were about 10 of these four spindle machines working making aircraft parts in that plant.

Before those, there were rotating duplicators following a hand carved template as far back as the 1860's. The ones I'm thinking of were developed to make rifle stocks fast enough to meet demand for the US Civil War.

Edited By Jeff Dayman on 07/09/2017 04:43:25

[HopperParticipant @hopper]

That's what apprentices were for! Standing at a machine all day turning out the same part over and over.

[Anonymous]

Lots of machines, each one set up for a single operation. There would be multiple cutters on a single arbor so several faces could be machined in one pass. Also multiple parts per pass if the parts were small. Many production mills used levers rather than handles and leadscrews and in later years pneumatic or hydraulic feeds. Basically piece rate workers, and lots of them.

Parts would also be designed to use the machines and tooling available, using as few operations as possible.

Andrew

[JasonBModerator @jasonb]

Probably more use of castings and forgings too rather than hogging things out of a billet.

Edited By JasonB on 07/09/2017 07:57:48

[jimmy bParticipant @jimmyb]

endless fixtures……………..

jim

[Ex contributorParticipant @mgnbuk]

These were used from the 1950's I believe.

Keller electric copy mills were used before that during WW2 to make aircraft propeller blades IIRC. The Kellers used AC motors running continuously & electric clutches controlled by contacts in the stylus assembly for the axis feeds. The stylus traced across a template, with the clutches being controlled to keep the pressure on the stylus in constant contact. With multiple milling spindles, several parts came off for each cycle.

I wired the last Hayes hydraulic copy mill to be built, sometime around late 1982 IIRC. I had been seconded to Hayes (Meanwood, Leeds) for a couple of weeks while at Boxfords (both part of the Brooke Tool Group at the time) when one of their electricians was off ill. At that time they were rebuilding copy mills that made the small compressor blades for jet engines (IIRC the machines were for Pratt & Whitney Canada) 4 at a time. One of the first service visits I made while at Broadbents (which became Broadbent Hayes) was to a Hayes copy mill at a forging company in Wednesbury (I drew the short straw on that one and the wiring of the last machine because I had seen one before !), so those machines were still being made and used into the '80s, long after CNC had become more affordable.

Other components were made with machines that ran simple cycles to limit switches & there were also plugboard controlled versions. At the time I was at Boxford (Sept '80 – August '81) they only had 2 CNC machining centres but had several "point to point" simple cycle milling machines. Multiple drilling operations were carried out with "tumble boxes" (machining fixtures with drill bushes) on gang drills.

Much more part handling, swapping parts from machine to machine with each machine set up for one operation. A bed casting for a South Bend style Boxford (for example) started off as a rough casting machined falt top & bottom on a planer, went to a "Duplex" mill for the milling of the top bed formation (all vees, flats & sides) at one pass using a gang milling cutter, moved to the Varnamo point-to-point section for the undersides of the vees & rack mounting faces milling, rack mounting & leadscrew bracket holes drilling etc. A headstock casting had the vee formation gang milled, then was mounted on a fixture using the vees on a CNC horizontal machining centre with a rotary table, where all subsequent maching was done at the one set-up – much less handling required.

If you want to make a great many parts, all the same, then transfer machines probably still rule. Hattersely Valves in Halifax used rotary transfer machines (Diedesheim or Vogel IIRC) to make brass valve bodies. The parts were held on a vertical axis platter that indexed through 8 or 10 postions. At each position was a machining head. The operator took a finished part from the platter & loaded a blank in it's place – on starting the cycle, the platter indexed one station & all heads completed their cycle. The part progressed around all the maching stations in order, so every cycle saw a blank loaded & a finished part removed. A bit challenging to set initially & used a lot of specially ground form tools, but once set & running the parts came out very quickly.

Nigel B

[Alfie PeacockParticipant @alfiepeacock58331]

Thanks for the replies especially Nigel`s informative post, I think that has answered my question.

Alfie

[Chris Evans 6Participant @chrisevans6]

"Vertical axis platter" as quoted from Nigel's post. Still used today but known locally as a "Tombstone".(not to far from Wednesbury) The toolmaking company I worked for was bought by a die casting foundry so I got to work on jigs and fixtures as well as die making. I did operate a Keller copy mill as well as many other copy mills in my toolmaking days. Deckle/Hayes/Cincinatti/Alexander are just a few I can remember. As for the mould and die work a lot of maths was involved to create the shapes along with fancy cutter grinding and rotary table work. Our saviour was the EDM or spark erosion machine several of which I used over the years. The CNC mill can now do in a week what would have taken a month or more. The CNC is also far more accurate and leaves less hand finishing. Glad I retired having learnt many skills the old way.

[MuzzerParticipant @muzzer]

There are still quite a few cam lathes in use. Our factory in China uses a lot of modern CNC machines but for some well-established jobs, cam lathes can still hold on by the skin of their teeth. The "program" is made by making a suitable camshaft that controls the various tools and cuts and timing. Fearsome looking things – and obviously take a lot of time and skill to set up but there's no electronics involved.

Video here showing one in action.

I also recall refitting an automatic bandsaw that could be programmed to cut a preset number of lengths of stock from a full length. That was entirely done with control relays, time delay relays, counter switches, limit switches and hydraulic valves (to feed and close the vises, control the arm etc). I replaced all the relays etc (about a dozen) and it got a new lease of life. Obviously a bandsaw has very limited functionality but these days it would be done with a PLC. In this instance it simply wouldn't have been worth ripping it all out and starting again.

Murray

[Alfie PeacockParticipant @alfiepeacock58331]

Again thanks for these posts, the Video is incredible I could watch these machines for hours.

[Author]

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