Author Topic: Chester 626 mill CNC Conversion  (Read 213083 times)

Offline Divided he ad

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Re: Chester 626 mill CNC Conversion
« Reply #550 on: April 06, 2013, 04:13:20 AM »
Quote
Wile on the subject weee rant , rubbing something back and fourth on a sheet of emery paper is NOT LAPPING ,  :bang: :bang: another  engineering term that has been bastardized .


I always said flatting.... But I suppose that's wrong? Since it don't come out flat!


But I ain't changing my vid's... Flatting it is!


Lapping is for cutting 2 part together ain't it?




Ralph.
I know what I know and need to know more!!!

Offline NickG

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Re: Chester 626 mill CNC Conversion
« Reply #551 on: April 06, 2013, 07:44:06 AM »
In the dictionary now it's either I think but as Rob said, I think probably originated from lapping together 2 mating surfaces so they fit each other. I think grinding in valves on a car engine was known as lapping? In these cases which is the lap though? I think the lap is the material in which the abrasive is embedded?
Location: County Durham (North East England)

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #552 on: April 06, 2013, 09:43:42 AM »
Did I mention my Chester 626 mill was a crock of sh*t  :Doh:


Decided to do a bit more checking this morning  ,,,,,,,,and it gets worse  :lol: :lol:

All blue areas are touches ,  Table to compound ,  :palm:
 

Compound to knee ,,,,,,,,,,,,,what the fook !



Lets see if the Y is  parallel with the X axis ,,,,,,,,,,,,,,,,,,,what was I thinking .






Oh well , note to self , build complete machine next time  :Doh:

Rob

Offline Stilldrillin

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Re: Chester 626 mill CNC Conversion
« Reply #553 on: April 06, 2013, 10:48:32 AM »
Aaaawww....... Rob!  :palm:

But. Look on the bright side....... You're the Guy with the nous to fix it!  :D

Commiserations Mate.

David D
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Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline NickG

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Re: Chester 626 mill CNC Conversion
« Reply #554 on: April 06, 2013, 11:09:12 AM »
Well I've learnt one thing from these posts - never, ever buy a Chinese machine of any type again as I don't have the skill to fully rebuild a machine like you have. Terrible, people still turn out good stuff on them but imagine how good it could be with a decent machine!
Location: County Durham (North East England)

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #555 on: April 06, 2013, 11:34:58 AM »
 :lol: :lol: David all I wanted to do was make new gib adjusters  :palm: 

Hi Nick , I totally agree as this is bogstandard for a hobby  import machine, absolutely shoddy workmanship ,cheap crap parts ,bearings ,screws , fasteners all utter rubbish .
 I personally would never touch a far eastern  import ever again .  From now on sticking with used machines from  German ,Swiss ,USA and UK manufactures . 


Rob

Offline micktoon

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Re: Chester 626 mill CNC Conversion
« Reply #556 on: April 06, 2013, 12:07:54 PM »
My heart goes out to you Rob ,
    its one step forward and two back when you find stuff like that...........it is sickening to think that when these things are made its more or less fraud really lol , they just make it look like a milling machine rather than work like one. I wonder how long they would last in a factory working shifts with contact points like that on the working surfaces ...................... What is your master plan to get around the problems Rob ?  Its not justice Rob but as David D says at least you will be able to overcome the problems, someone else with less gear and knowledge would now be thinking of scrapping the thing  :palm:
  I think all you can do is look at it as a challenge and think of it as character building :hammer:  :poke:  :bang: as they say  :scratch: , while your watchers sit back  :coffee: :coffee: and wait knowing it will end up  :drool: :drool: :bow: in the end and we will have all learnt something on the journey , how to fix ...........as well as don't get one in the first palce :thumbup:

 Best of luck Rob and I hope its the last of the nasty suprises for you  :thumbup:
  Cheers Mick

Offline krv3000

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Re: Chester 626 mill CNC Conversion
« Reply #557 on: April 06, 2013, 04:27:05 PM »
well rob it will be worth it in the end chin up it will run one day

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #558 on: April 06, 2013, 04:47:27 PM »
Evening Lads  :)


Well after a sausage sarnie and a brew I decided there was no way I was going to hand scrape a possible 20 thou out casting ,so it was whacked onto the mill for a skim.


Y axis



X axis


I just took the bare min of the faces , just enough to true them.

Try for flatness .




Test for parallel .





Thats a few tenths of a thou over just short of 12 inches .  0.008 mm , a tad better I would say  :coffee:

Rob


Offline doubleboost

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Re: Chester 626 mill CNC Conversion
« Reply #559 on: April 06, 2013, 04:51:55 PM »
Looks the dogs now mate
Have you ever fancied working in China :lol: :lol: :lol: :lol:

John

Offline krv3000

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Re: Chester 626 mill CNC Conversion
« Reply #560 on: April 06, 2013, 05:27:14 PM »
lol by the look of robs ther still in the stone age

Offline Stilldrillin

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Re: Chester 626 mill CNC Conversion
« Reply #561 on: April 06, 2013, 05:43:24 PM »
Well done! I had every confidence in you Rob.  :clap: :clap:

Especially after a sausage sarnie........  :thumbup:

David D
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Still modifying bits of metal... Occasionally, making an improvement!

Offline Mayhem

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Re: Chester 626 mill CNC Conversion
« Reply #562 on: April 06, 2013, 11:37:34 PM »
Excellent work there Rob.

Offline doubleboost

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Re: Chester 626 mill CNC Conversion
« Reply #563 on: April 07, 2013, 05:36:48 AM »
You need to get Bob to look at that clock
It seems to be "stuck" :bow: :bow: :bow: :bow: :bow:
I wonder if my mill is the same  :doh: :doh: :doh: :doh: :doh:
John

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #564 on: April 08, 2013, 02:32:59 PM »

I wonder if my mill is the same 
John

20 Tabs , a sausage sarnie and a brew I bet it is  :)




The fun continues  :lol: , with the compound slide all squared up it was trial fitted to the knee casting , as expected I knew i would have to machine some from the top of the Y dovetail , But the gap was not even  :scratch: I could get nothing in one side and a .0025 feeler in the other , odd



so a bit measure up . :Doh:

 


Oh well it need machining anyway . set up on mill using the four corners as reference points  to get it level both ways .I have to be careful of what gets machined away as it all has a knock on effect.   






with that done a light skim was done to true the face .



Now i checked all four corner points , all crack on .




now the middle , remember this machine was less than a year old when I bought it .




both sides have a nearly 3 thou bend in the middle and its not wear .its Fooking CRAP machining  :bang:




Rob

Edit : missed photo out
« Last Edit: April 08, 2013, 06:07:22 PM by RobWilson »

Offline doubleboost

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Re: Chester 626 mill CNC Conversion
« Reply #565 on: April 08, 2013, 03:12:55 PM »
Nice set ups Mate
I like the machine jack :thumbup: :thumbup: :thumbup: :thumbup:
At least the new mill came in handy
John

Offline loply

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Re: Chester 626 mill CNC Conversion
« Reply #566 on: April 08, 2013, 04:56:42 PM »
Rob,

Forgive my ignorance but isn't the surface which you appear to have machined a clearance surface? I thought the ways were the bits on the bottom? I can't imagine it's designed to contact both on the top (the bits you've written on with pen) and the bottom (the bit your mic gauge is sitting on), so what am I missing?

Rich

Offline loply

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Re: Chester 626 mill CNC Conversion
« Reply #567 on: April 08, 2013, 04:58:52 PM »
Having looked at it more closely I think I realise that it is just a 6-surface bearing, must be complicated to scrape in!

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #568 on: April 08, 2013, 05:22:43 PM »
Hi Rich

Your correct the top is a clearance fit and dose not contact the compound , but because I had machined the compound bearing surface flat and true .

  they did  touch , as I new they would , I had to take 20 thou off the compound  , so I   machined the knee dovetail to clear the compound slide so the slide bearing surface can sit down on the knee bearing surface . Now that the top surface of the dovetail is flat I am just using that surface to shows how bent the Knee way bearing surface is .

I have to box clever here as I dont have much material to play with . Also pre made parts will have to be altered  :palm: I really should have inspected the machine before I started .  note to self there .

Rob

Offline micktoon

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Re: Chester 626 mill CNC Conversion
« Reply #569 on: April 08, 2013, 05:27:55 PM »
  Hi Rob  :palm:   what can you say , it looks like a case of what can you trust to be right in the first place to then use as datum point  :scratch: , do you think any of this type of thing is due to them machining castings before they have time to season and settle the stresses out ? or they just machine them by eye and that will do for the quality standards they operate on. I am sure you will get it fettled in the end  :thumbup:
 looking on the bright side its making the effort you spent getting your new mill sorted out and making that flycutter..... worth every god dam second  :ddb: :bow: :bow:

 Cheers Mick

Offline doubleboost

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Re: Chester 626 mill CNC Conversion
« Reply #570 on: April 08, 2013, 05:30:57 PM »
Mick
Never mind season, they will be "machining" them still warm from the sand  :jaw: :jaw: :jaw: :jaw: :jaw:

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #571 on: April 08, 2013, 05:43:37 PM »
Hi Mick

I never thought I would need the flycutter to fix the 626 , just made it as an in fill project , thought it may come in handy some day  :palm:, pleased I did make it now .

New mill is worth its weight in tabs .


Rob
« Last Edit: April 08, 2013, 06:13:55 PM by RobWilson »

Offline Jasonb

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Re: Chester 626 mill CNC Conversion
« Reply #572 on: April 09, 2013, 02:51:27 AM »
So Rob given that all the flat surfaces were machined with a bananna cutter is it fair to assume that all the angled faces of the dovetails will no longer be true to your new flat faces and all have to be skimmed?

J

Rob.Wilson

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Re: Chester 626 mill CNC Conversion
« Reply #573 on: April 09, 2013, 03:51:20 AM »
Correct Jason , I will hand fit the dovetails . There is one saving grace in  that they actually got the dovetails parallel.


Rob


Offline Pete W.

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Re: Chester 626 mill CNC Conversion
« Reply #574 on: April 09, 2013, 04:41:45 AM »
Hi there, all,

Rob,

I've been following this thread with interest.  I find the work you've been doing absolutely mind-boggling and I feel for you as you find each new problem.  It must be horrible to be sort of trapped by the work you've already done - giving up now would be enormously costly in terms of your investment so far.

The best I can say is 'hang in there!', I'd like to encourage you somehow, though I speak from such an inexpert level.

At least you have other machines to bring to bear on the Chester - imagine the plight of someone just having a dud machine and only their bare hands and a file and scraper or two!

It does give me an appreciation of the achievements of the pioneer machine tool builders, starting from very little and building-up to some of the huge but precise machines I have only read about and seen in pictures.  One such that comes to mind is the gear-cutting machine that floated in/on a pool of mercury to isolate it from ground tremors, was it Browns in Manchester?  I think it was that one that made/makes the big double helical gears for naval gearboxes.

Anyway, I say again, 'hang in there'.
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!