Trying Out The Rapid Turn For The First Time

[Bob RodgersonParticipant @bobrodgerson97362]

I Received the Tormach Rapid Turn Attachment about three weeks ago but due to having to much work on for the mill I have been unable to get round to fitting the wiring,JB and sockets that have to be fitted to enable the VFR to speak to the Turning attachment motor and at the same time isolate the mill spindle.

I finally got that done on Friday last week and have had a few days of playing with it. I made a thingywatchamacallit and it turned out perfect.

Edited By Bob Rodgerson on 24/08/2016 19:07:56

[Bob RodgersonParticipant @bobrodgerson97362]

Trying Out Tormach’s Replacement for the Duality Lathe turning attachment for the PCNC Milling Machine

[Grant NicholasParticipant @grantnicholas81434]

Thats a nice addition to your 1100 Bob. Produced a good finish to. How long did it take to setup on the table?

G.

[Bob RodgersonParticipant @bobrodgerson97362]

Hi Grant,

it took a good couple of hours because this was the first time I have set it up. I had to drill and tap a hole in the spindle adaptor that holds the tool post for a stabilising bar to be fitted and I also fitted a piece of angle bat to carry the tray in front of the mill table at the left hand end so that I can leave it fitted when I use the lathe on the mill. However I would reckon that it will take about 15-20 minutes in the future. The finish it produced was far better than any I would have got from using the manual lathe.

[John HaineParticipant @johnhaine32865]

Very impressive! Mind you, one does get the impression at various points in the video that the toolpost is made of indiarubber, but I expect that's either the lens or the video encoding!

[JasonBModerator @jasonb]

Looks like it will have some uses

Regarding the chatter when doing the bell mouth, when cutting in the direction you have it the cutting width is very wide as there is a lot more of the tip in contact with the work due to the shallow angle on the "back" of the insert. If you were to cut from the outside in then the "front" of the tip will have less width of metal to remove for the same given depth of cut. Hopefully should result in less chatter.

The 0.010" roughing cuts do seem quite fine and are likely whats making the swarf so unmanagable. I also noticed that your spray mist seems to send quite a bit of coolant into the back of the motor.

[Anonymous]

Bob: Impressive stuff! The Rapid Turn looks like a real bit of kit compared to the Duality; I'm really glad I decided against buying the Duality. It's a little disappointing though if the proximity switch wasn't adjusted properly?

That swarf definitely needs sorting, a real birds nest; then you can walk away and let the machine get on with it. I think you have a handle on the issues though; far too low a DOC and the wrong type of insert. Spindle speed seems less important, but I've found feedrate is critical to get the chip breakers working properly. I don't think there was mention of feedrates?

I assume that you had the toolpost from the Duality lathe days? That seems a slight weakness to me. Personally I'd have used a profiling insert, but I'm not sure if the holders would fit the existing tool post.

I'd certainly like a Rapid Turn, but for me it would be a bit of an indulgence as I have other means of turning fancy shapes, if needs be.

Keep us posted on further developments.

Andrew

[Bob RodgersonParticipant @bobrodgerson97362]

Andrew,the Rapid Turn is in a different league to the Duality. The notable difference being the motor size, wirh a 1 H.P. motor and a low and high belt position it should have plenty of grunt to tackle some of the larger jobs, though it has been bought mainly for making custom bolts and studs. The Duality didn't have the threading capability that this does.

Getting it up and running was not without problems,as already mentioned, the chuck came loose from the backplate while I was making the thingywatchamacallit. It took a while for it to dawn on me what was happening. I thought that it was some sort of low frequency chatter at first. I was able to get it tightened up without any problems but that sort of thing should have been checked before despatch.

Also the motor has been wired incorrectly and everything is running in reverse to what it should do, again an easy fix, just swap two wires over, but it should have been checked before despatch. Again it took a while to register with the grey matter that it was running the wrong way, short term I just went into the G-code and put in M-4 to get the correct rotational sense then when I had time I checked in the manual that comes with it and sure enough it confirmed my suspicions.

Apart from those niggles it is a great bit of kit and will prove worth while to me.

One thing I don,t like is the proximity to the front of the headstock casting of the two mounting slots in the baseplate. It is impossible to get an open jaw spanner onto the nuts on the Tee slot studs they are so close. I presume they are positioned here so that the attachment can be mounted as far back as possible on the mill table. This would be needed if you were doing any work that involved using a tailstock.

I will probably cut some extra holes in the baseplate and do away with the central hold down fitting because it is in direct alignment with the nose of the chuck and effectively steals 1" of throw.

I will post on progress when I get round to making some vernier timing sprockets for vintage motorcycles.

When I was playing with it making the thingywatchamacallit I didn't pay any attention to feeds and speeds, other than to go very conservatively with the DOC so that there was no chance of a stall out which used to happen regularly with the Duality.

P.S. I enjoy reading your gliding posts, I used to work for a drilling Manager that had a half share in a glider at Aboyne in Aberdeenshire, his partner in the share I believe was a british champion in aerobatics or long distance gliding. I marvelled at the distances that they used to achieve sometimes going as far south as Leicestershire on thermals only.

Another acquaintance used to fly gliders out of Millfield in Northumberland, he, like you used to fly the club tug aircraft, eventually this led to him obtaining a commercial pilots licence and he is now flying for one of the Major airlines.

My son is currently at Oxford Air Academy taking an ATPL. He is off to Phoenix in October for the flying part of the course. I have had to lend him the money to do it, hence me still working after retiring from the Oil Industry

[Bob RodgersonParticipant @bobrodgerson97362]

Hi Andrew, I forgot to mention that the tool post was part of the original Duality set up. The only modification being the addition of a stabilising block that needed a hole drilled and tapped so that it can sit directly behind the tool post and stop it from moving. It is an area that could be greatly improved by making the collar that fits around the spindle housing much more beefier and with multiple positions to enable gang tooling. I'm pretty sure I will look into this when I get more time and make something that is better and sturdier.

I have kept the 4th axis attachment that was fitted to the duality and I reckon I can easily make an adaptor that fits into the collet draw bar tube to extend the spindle to the rear and fit the attachment to it thus giving me 4th axis capability without having to take the work out of the mill.

[John Stevenson 1Participant @johnstevenson1]

It's a shame after going to all this trouble with the Rapid Turn that they never fitted the 4th axis option, instead plumping for a manually operated index plate on a CNC ?

[Bob RodgersonParticipant @bobrodgerson97362]

Hi John, I'm with you on those thoughts. The attachment itself is so simple. Just a headstock set in an alloy casting wit a 5-c collet and drawbar arrangement for work holding and a proximity switch for RPM feedback to the controller so the additional arrangement of adding 4th axis capability wouldn't have been that difficult.

I suppose that I have all the components necessary to adapt a small lathe headstock and tailstock complete with 4th Axis facility if I wanted to, the only real problem would be the weight involved.

[MuzzerParticipant @muzzer]

I see, so it can do speed synchronisation (with the table movement), to allow single point turning – but not positional control of the spindle at zero speed. So it's lacking a position encoder / resolver and uses an induction motor with encoder for speed control. I see that it uses the spindle VFD to drive the Rapid Turn (you swap the connection over), so even if you managed to get it working as a 4th axis, you'd need to fit a second VFD for the spindle.

I suppose this makes it simpler and cheaper to implement but as you say it seems a pity not to have gone for a proper 4th axis solution. But a 1HP servo drive and motor would have cost a lot more.

They say "RapidTurn™ transforms your Tormach PCNC mill into a 5C chucker lathe.", so it's basically a lathe rather than a 4th axis. They already do (low speed) 4th axis rotary tables, so I suppose you could say they have it covered already.

[Anonymous]

Bob: Thanks for the additional information. I had a read through of the Rapid Turn manual on the Tormach website. The unit looks to be a solid bit of kit. One question I had has been answered; it shares the VFD with the mill spindle. Presumably there's a terminal block and changeover switch somewhere? Is it automatic or do you have to remember to change over? Of course in an ideal world it would do 4th axis as well. But I guess that would impact on the sales of rotary tables, and also considerably increase costs for the Rapid Turn. So I think Tormach have positioned it pretty well. I've used my 4th axis quite a lot. The Rapid Turn looks good and I'd love one to play with. But since I have a repetition lathe and hydraulic copy unit it would be duplicating capability to some extent.

It's some years since I flew at Aboyne; we used to go every year starting in the early 90s. I had some excellent flights there, and after a couple of false starts eventually did my diamond height twice in one week. It was quite intense flying, a lot of gliders in the air, challenging weather and narrow runways. I've seen more wheels up landings there than elsewhere put together. The main issue was that we never found a pub/hotel that did good food and good beer. You either got a good real ale and so-so food, or great food and 70/- or 80/- beer.

Likewise I've been flying at Milfield since the early 90s, when they were on the old site at Galewood. I've had some excellent flights at Milfield too, including my best height (23000 feet) and the roughest tow I've had in the UK. It's a great club, good facilities and friendly members.

PM me the names of the people you knew, it's quite possible I knew, or at least knew of, them.

Good luck to your son. I used to get asked why I didn't become a commercial pilot. It never really occurred to me, I was far too obsessed with engineering.

Andrew

[Bob RodgersonParticipant @bobrodgerson97362]

BobHi Andrew,

I cannot for the life of me remember the surname of Martin who used to fly out of Millfield. All I know is that he graduated from Pattern Flying Model Aircraft (at which he was excellent) to flying gliders from Millburn and eventually building enough hours to enable him to get a licence to fly the Tug. From there he progressed to commercial aviation. He would have been in his early thirties at the time he was flying the Tug at Millfield shortish medium build with dark hair.

I think he was a maintenance Engineering Manager for a Pharmaceutical company based in Morpeth. I,m not surprised you got a rough tow out of Millfield if the prevailing wind is anywhere out of the west you must get an awful lot of turbulence in the lee of the Cheviot hills.

Going back to the Rapid Turn, it doesn't have a switch but you have to instal a Rapid Change kit. Basically it's a JB that takes the power wires from the VFD and they terminate at a socket. You remove the JB from the spindle motor and replace it with a plug. The rapid turn also has a similar plug. There is no switch, instead you have to change the settings for whatever is installed after shaping the plugs over, all very simple in the set up screen.

[Anonymous]

Thanks for the info on the installation and motor drive changeover. It seems pretty well thought out.

I think that the worst turbulence at Milfield tends to be southerly or south-westerly. The wave can set up at the head of the College valley, so quite local to the club. But you have to tow through the rotor to get there. At least you get some advance warning as you can see how the tug is reacting to conditions and can anticipate the control movements required.

I have a recollection of a Martin flying the tugs. If I recall he is now chief tug pilot? I remember him because we both got a b0llo0cking off the duty instructor a couple of years ago. He had asked me if I wanted a tow behind the Eurofox to explore the wave. I said yes, so we lined up and were ready to go when the duty instructor demanded we stop and re-position as we were about to tow off with a pretty stiff crosswind. Didn't worry me, and presumably didn't worry the tug pilot, but one has to do what one is told!

I've sent you a PM as well.

Andrew

[MuzzerParticipant @muzzer]

Bob / Andrew

Dunno if you have been following Threadexpress over on Youtube but he recently bought a Rapidturn for one his Tormachs and has been having a few thoughts about how to improve it. He seems generally impressed so far.

Murray

[Bob RodgersonParticipant @bobrodgerson97362]

Hi Murray,

thanks for the heads up on Threadexpress. I have responded to his very interesting postings on youtube,. I am still in the very early stages of exploring the Raid Turn but have had thoughts on gang tooling and extended distance between centres. I have a tailstock ready to fit, I just need to make a raising block for it. I am however struggling, between one or two big projects, with diameter control of the workpiece but I will get there given time.

[Author]

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