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Gallery / Re: 5C Collet Chuck finally in service.
« Last post by Joules on April 19, 2018, 06:09:34 PM »
Yep, got a few square and hex collets here.  I will probably set the chuck and plate up on a bar then see how much it needs balancing.   Not expecting to run at high speed, plenty of meat on the backplate to get the static balance right without messing the chuck body.
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Gallery / Re: 5C Collet Chuck finally in service.
« Last post by awemawson on April 19, 2018, 06:02:48 PM »
The nice thing about 5c collets is you can get not only round, but also square and hexagonal ones  :thumbup:

If you are running high speed it is probably worth machining the few thou body run out off to get better balance

( no point if your work is all low spindle speeds)

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Gallery / 5C Collet Chuck finally in service.
« Last post by Joules on April 19, 2018, 05:56:00 PM »
I had this sitting around for a while.   It was going on another lathe but I ended up getting a D1-4 backplate so it could go on the big lathe.   So glad I got round to doing it, I just clocked the runout on my collet to about a tenth of a thou.  The chuck body runs out by several thou but the collet and register seem accurate.  I was expecting to need some play to get it this accuate, maybe I was just lucky.  The back plate was a bitch to machine though, countersink all holes prior to tapping and clean up with a fine stone to clear any burrs.  Now to build up my 5C collet collection, love the versatlity of emergency collets.
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Project Logs / Re: New Tractor Shed
« Last post by awemawson on April 19, 2018, 04:17:27 PM »
Hardwood in almost any form is always very welcome Pete  :thumbup:
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Project Logs / Re: New Tractor Shed
« Last post by Pete. on April 19, 2018, 03:59:41 PM »
Aww Andrew you should have told me you were looking for some decent hardwood, I just skipped some huge mahogany window frames this week.
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CNC / Re: Electricuting the lead screw
« Last post by eskoilola on April 19, 2018, 01:51:45 PM »
@eskoilola
if you haven't read the link I provided, <snip>
Actually I DID read the article(s) and this seems to be somewhat what I want to do.
- I want to maintain the manual controls touch and feel as much as possible
- I want to have the thing to be a "fly by wire" - probably G-code compliant
- I want to do this as far as possible with the original controls
- I want to have sex with my lathe ....

What I would really hate is a big bunch of buttons and some reverse polish notation aka Sinclair scientific calculator from the 70's - it was a really sexy gadget at it's time. Had one and hated it all the way.

For example. At the moment there is a automatic feed on/off lever. That lever would be really easy to modify to be a forward/reverse feed control. On center position (positive lock) it would allow manual control with apron handwheel or the handwheel at end of the lead screw. When away from the center the feed would be equally faster to the desired direction.

Same kind of thinking would go with the cross slide. This time the feed would be controlled with the ex-half nut lever which would now be repurposed for that function.

That Slo Syn motor can do (per spesification) 10.000 steps / second (aka 2500 Hz) - quite amazing for a large stepper like that. I am pretty sure that the torque is an overkill - which is not bad. That 10.000 steps/second amazes me as I also have done my fair part of stepper drivers. The best ones had a switching power supply with constant current output. This means that the voltage rises with the drive frequency. These could easily do 2.000 steps/second but after that most of the steppers went berzerk. That sort of speeds also require acceleration time. Assuming that the ball-nut I have has a 3 mm pitch (same as the current lead screw) the max speed would be then 150mm / second. It is enough for most purposes. I have never measured the pitch of the ball-screw but if my memory serves me correctly - it is more.

When it comes to accuracy there is one unspoken element in the lathe, the compound. You figure it out from there. Auto-feed in the compound ... Hmmmm ..... Maybe a angle sensor and whatnot.

As PK very nicely put it - all this is really cheap - one just needs 10.000 worth of equipment to do it  :beer:

Further more - all this is purely academic as long as I am on my assignment here and my home is there. That being said - well thought is halfway done.




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Project Logs / Re: New Tractor Shed
« Last post by awemawson on April 19, 2018, 09:58:56 AM »
The weather is improving and things are drying out, which means I could attempt to shift the stock pile of topsoil from the field to round the back of the Tractor Shed. It was still a bit gloopy, but will dry out far faster now it is piled in 14 pyramids round the shed rather than one massive pile in the field. An estimated 28 tons - probably need a bit more by the time that is spread about.

Went pretty well until I reversed the digger into a Willow Tree and flattened it  :bang: In all fairness it was on it's last legs anyway after a friends cattle had taken a liking to it back end of last year.

We are holding an 'Open Tea' on Sunday in support of the local Hospice (St Michael's) and we are a bit short of outside seating - now a recent visit to the tip liberated a pair of cast iron Bench Ends, just short of the slats - I was sure that I had a big oak beam I could slice up but it must have been used on other projects, so before I started moving earth I sliced up some scaffold planks and gave them a coat of varnish - not as good as oak but they'll last a couple of years or so.
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CNC / Re: Electricuting the lead screw
« Last post by JHovel on April 19, 2018, 05:38:37 AM »
@eskoilola
if you haven't read the link I provided, there is provision for and a design for an "electronic half nut" for this ELS controller. It works just as you describe: you move it a certain amount in either direction and it moves the apron at a preset cutting speed. You can move it a bit further and it accelerates progressively to a defined 'jogging' speed. Pretty much like you would use the apron handwheel. He used the analogue input of the control chip to achieve this with a simple potentiometer. I used an electric wheelchair handle with pot to do this.
Finer control is provided by the manual pulse control on the panel. The whole thing is very functional.
It also has a port to connect it to a full CNC controller, should you want to use MachIII, G-code or whatever to operate the lathe.
The ELS by itself just gives you better control over feeds and cutting depth, and includes all common threads, all common tapers and taper threading in memory. It withdraws the cutting tool at the right time and allows nice consistent cutting and threading at the correct speeds for the tools used. Cutting threads a high speeds with nice fine depth of cuts automatically is very nice - and a bit exciting when they finish against a large shoulder!
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The Water Cooler / Re: Legislation Outlaws Home Workshops
« Last post by Fergus OMore on April 19, 2018, 03:20:38 AM »
Poisson D'avril or one man's mete (meat) is another man's poison( Poisson)

It 'a-puns like that

N




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The Water Cooler / Re: Legislation Outlaws Home Workshops
« Last post by awemawson on April 19, 2018, 01:47:10 AM »
Matthew,

Look at the date it was posted, April 1st, All Fools Day  :lol:
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