Author Topic: Thread cutting video part 2  (Read 7096 times)

Offline doubleboost

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Thread cutting video part 2
« on: October 28, 2012, 01:24:47 PM »

John

Rob.Wilson

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Re: Thread cutting video part 2
« Reply #1 on: October 28, 2012, 02:06:14 PM »
 :lol: :lol: :lol: :lol: :lol: thats a quality nut mate , these imported machines are utter crap , just goes to show that they are consistent at producing crap , your mill being a good few years older than mine  :bang: :bang: :bang: :bang:

good video  :thumbup:  do you wants a few more wobble nuts  i have a few spare  :lol: :lol: :lol: :lol:


Rob

Offline BillTodd

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Re: Thread cutting video part 2
« Reply #2 on: October 28, 2012, 04:26:03 PM »
Nice video John - I liked the use of the close-up window  :thumbup:

Just thinking:

Since you have a VFD on your lathe, it'd be a doddle to add an electrical threading stop  (i.e. a micro-switch mounted on the bed) and high speed reverse 

Bill

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Offline micktoon

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Re: Thread cutting video part 2
« Reply #3 on: October 28, 2012, 06:01:30 PM »
  Hi John , another quality video mate  :thumbup: :thumbup:, Like Bill I liked the small window showing the detail, a nice touch  :drool:. Keep them coming  :clap:

 Cheers Mick.

Offline krv3000

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Re: Thread cutting video part 2
« Reply #4 on: October 28, 2012, 06:22:59 PM »
well dun john      :drool:

Offline Brass_Machine

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Re: Thread cutting video part 2
« Reply #5 on: October 28, 2012, 09:36:24 PM »
Hiya John!

Caught your video... I like the production on it!

Scanned some of your other videos. A JET CART???

Thought I was insane...

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline nel2lar

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Re: Thread cutting video part 2
« Reply #6 on: October 28, 2012, 11:09:10 PM »
we would expect nothing less! very nice video and narration. keep up the good work
:clap: :beer: :wave: :proj:
Nelson Collar

Offline NickG

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Re: Thread cutting video part 2
« Reply #7 on: October 29, 2012, 06:21:01 AM »
Brilliant video John, thanks. Shame there are plenty of idiots on youtube making comments. Jet Kart is awesome but you wouldn't get me sat on it!!!

That nut has just confirmed I am never buying another Chinese machine - I expect my mill needs an entire rebuild. The more I wind the table across, the bigger the error gets going from the dial - must be a big thread pitch error. Don't think the table is flat either and there is run out in the spindle unless the quill is nipped slightly! Pile of cr@p!

Location: County Durham (North East England)

Offline andyf

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Re: Thread cutting video part 2
« Reply #8 on: October 29, 2012, 06:32:51 AM »
I'll add my applause to the general acclamation, John. A very instructive pair of videos, and I'm looking forward to Part 3. Sure beats watching the TV.

Nick, could your feedscrew be metric pretending to be imperial, or vice versa? That would produce an error of around 1.6% between what the dial says and what proper measurements show.
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline Fergus OMore

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Re: Thread cutting video part 2
« Reply #9 on: October 29, 2012, 07:23:38 AM »
I'm wondering about Nick's machine. As far as my experience goes, the Chinese mills have a few potential problems. The first that I hit on my Warco mill drill was or were the gib adjusting screws. They were pretty sloppy and allowed 'push and shove' of the tapered gibs. I would have thought that new screws coud be machined- and fitted more tightly to the recesses in the gibs. ( a thought, no more) Again, the nut is one which can be nipped up- or mine can. The leadscrews are substantial enough.

I'm saying all this because in the last century( ye Gods) I got a set of home castings that had been dropped at Gateshead Tech, part machined and I built up a Westbury- no, not a Dore Westbury- and found all sorts of errors or adjustments were needed to take up it to some degree of accuracy.

I may be wrong but that's my two pennorth for what is worth.
Cheers

N

Offline NickG

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Re: Thread cutting video part 2
« Reply #10 on: October 29, 2012, 08:28:22 AM »
Possibly Andy, I've never thought about that or looked at the pitch of it. There are 30 graduations and it says each one is 0.002" - didn't realise until just now it says each is also 0.05mm so guess it's really a 1.5mm pitch.

So just as a sanity check, as you say, If I give it say 10 revolutions I'm expecting it to go 0.6 of an inch = 15.24mm but it actually goes 15mm and that's the 1.6%. Doesn't sound a great deal but if positioning holes say 4" apart - I wind the dial 66 times plus 40 thou and it actually moves 100mm - 1.6mm out, enough to cause a problem!

I will do some checks on that Andy - bit of a school boy error on my part if it is that!  :lol:

Fergus, I think the gibs are tight, I've never noticed them move but then again haven't been looking for it. I'll have a look into that too. Am sure I clocked the table one and it got higher towards one end! Judging by the some of the errors on the 626s that John and Rob have shown, I wouldn't put it past em, obviously is no quality control. I was thinking buying a 626 would be a massive improvement for me but I won't be giving that any more thought.
Location: County Durham (North East England)

lordedmond

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Re: Thread cutting video part 2
« Reply #11 on: October 29, 2012, 08:29:22 AM »
another great video there John

well done


pretty poor nut you have there they do not know the sequence of pops  eg bore , screw cut & face off whist still mounted in the chuck , or maybe it was a stick and rusty nail they used  :D

Stuart

Offline andyf

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Re: Thread cutting video part 2
« Reply #12 on: October 29, 2012, 10:21:59 AM »
Nick,

Using metric screws and the fiction that 0.040" = 1mm seems common on budget Chinese machines. My lathe is "imperial", but the only imperial thing about it is the leadscrew. The feedscrews on the cross slide, topslide and tailstock ram are all threaded 1mm pitch, but with dials marked in inches. As your example shows, that creates problems on the miller, but it isn't so bad on the lathe. If I wanted to reduce a 0.500" diameter to 0.200" and relied only on the "inch" dial, the error would be on the safe side, and a bit more would need taking off. But I don't rely on the dials, and use a micrometer when getting close, which would show that another cut is needed. That's better than trying to put metal back on again. 

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline NickG

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Re: Thread cutting video part 2
« Reply #13 on: October 29, 2012, 11:34:27 AM »
Good point Andy, at least it leaves stuff on the large side on the lathe. I guess for me a DRO would transform the milling machine - esp if I can get the table trued up etc. Don't fancy making new screws like John - there's not as much weight to support on mine with just the head and motor so guess it should last longer!

Location: County Durham (North East England)

Offline DaveH

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Re: Thread cutting video part 2
« Reply #14 on: October 29, 2012, 03:47:39 PM »
Super video John,  :bow: :thumbup: :clap:

I think you should go into the film business
 :beer:
DaveH
(Ex Leicester, Thurmaston, Ashby De La Zouch.)

Offline krv3000

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Re: Thread cutting video part 2
« Reply #15 on: October 29, 2012, 06:23:02 PM »
as per john well showen and a brill job  :bow: :bow:

Offline Pete49

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Re: Thread cutting video part 2
« Reply #16 on: October 29, 2012, 10:13:47 PM »
A well done how to but can I ask what language the voice over is narrated in? I see Johns lips move but can't  work out why not just do it in english  :lol:
Pete
oops..........oh no.........blast now I need to redo it