Author Topic: GhT geared and retracting top slide  (Read 2642 times)

Offline Bjorn_B

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GhT geared and retracting top slide
« on: June 12, 2016, 09:34:41 AM »
Got this delivered the other day...

20160609_174553 by Bjorn Bursell, on Flickr

Need to think about that leadscrew, can't live with a imperial one as the other slides on this lathe is metric. Divisions on the existing top slide are strange too, (2mm pitch with 40 divisions...) I don't think I ever have used the top slide for diametric work.

Cheers!

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #1 on: June 12, 2016, 05:48:34 PM »
So a new 2mm left hand pitch leadscrew was made instead (or rather a 1,999mm pitch). Thanks to Grahams excelent screwthreading clutch, this was "done in a jiffy". Oh, bronze chips are form making a new set of input gears for said clutch, lost a tooth on one of the tufnol gears due to over enthusiasm. Bronze input gears from here on...

20160612_140146 by Bjorn Bursell, on Flickr

Finished result, the thread looks a bit thin for a true acme form, but I have other plans so not to worry..
20160612_141123 by Bjorn Bursell, on Flickr

Will make a try for a Acetal leadscrew nut (Evan method), this is the first test, no backlash at all and reasonable free running...
20160612_181525 by Bjorn Bursell, on Flickr

« Last Edit: June 12, 2016, 08:07:39 PM by Bjorn_B »

Offline Admiral_dk

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Re: GhT geared and retracting top slide
« Reply #2 on: June 12, 2016, 11:24:41 PM »
Hi Bjorn

Thank you very much for this little titbit about the nut.

Per

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #3 on: June 26, 2016, 09:32:03 PM »
*****Updated*****

Been slow here for some time, for reasons I won't bore you with...

Anyways, a session at the mill today, made a start on the body, will do the outline machining later..

20160626_162305 by Bjorn Bursell, on Flickr

All work was on the mill with drills, boring head and reamers, I have a self feed quill on this, very useful..

Also made the sleeve (Added pictures now), but different method to what GHT mentions in his book (a laborous job that also calls for a mandrel to be made up....) made it fit into the bore of the body first, then transfered to a dividing head to mill flats (115 degree spread) and then back to the myford to drill, bore and ream the centre hole after indicating the outer surface in the four yaw. After parting of it is job done... The method GhT mentions in the book is more tedious.

20160627_153350 by Bjorn Bursell, on Flickr

20160627_153428 by Bjorn Bursell, on Flickr

« Last Edit: June 27, 2016, 04:47:32 PM by Bjorn_B »

Offline Chipswitheverything

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Re: GhT geared and retracting top slide
« Reply #4 on: June 27, 2016, 12:34:18 PM »
Hi Bjorn, you have a very interesting project underway.  Was the acetal feed nut made by a process of heating and squeezing the plastic blank around the finished Acme thread?  I've read about it on other forums, but not tried it.

Yours, Dave

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #5 on: June 27, 2016, 06:19:31 PM »
Dave, it is heatformed. A split, hollowed out piece of POM, is clamped in the vice, heat applied to the leadscrew (carefully). Outer surface machined afterwards

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #6 on: September 09, 2017, 08:03:23 AM »
Been at this for little wile again, still mulling over the leadscrew.. in the meantime a short video of the quick-step in action miling the handle boss stop faces.


Online steamer

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Re: GhT geared and retracting top slide
« Reply #7 on: September 09, 2017, 11:21:12 AM »
Hey Bjorn,

What material did you use for the leadscrew?

Nice finish on that...

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #8 on: September 09, 2017, 11:38:40 AM »
Leadscrews i made in posts above will be discarded I think, as I remember they where made of ordinary EN1 quality.

Online steamer

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Re: GhT geared and retracting top slide
« Reply #9 on: September 09, 2017, 12:05:25 PM »
Leadscrews i made in posts above will be discarded I think, as I remember they where made of ordinary EN1 quality.

OK....I think in the states that would be 1018 CR.....wow   Nice finish there!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #10 on: September 09, 2017, 05:28:53 PM »
Most of my time seem to be made up of stepping between the mill (or lathe) and these two sheets of conversion tables. I made these in excel and stapled them to the wall between the lathe and my marking out space a long time ago. Been of endless help for me (metric head, metric machinery making mostly things measured in inches)..

20170909_173845 by Bjorn Bursell, on Flickr

20170909_173853 by Bjorn Bursell, on Flickr

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #11 on: September 10, 2017, 12:08:04 PM »
Bit of time in the workshop today, started on the gearcase block. A piece of aluminium squared up, marked up and drilled/bored/reamed

20170910_094523 by Bjorn Bursell, on Flickr

Piece is then transfered to a four-yaw for scooping out room for the gears

20170910_095808 by Bjorn Bursell, on Flickr

Decided to play a little with the qiuck-step here, this is the lowest possible spindle speed my lathe is capable of, it is about 8,5 rpm


Turned out to be a good thing, the recess would call for a trepaning tool otherwise

20170910_122400 by Bjorn Bursell, on Flickr

After this, turn around in the four-yaw, and more lathework..

20170910_121900 by Bjorn Bursell, on Flickr

I miss 2 countersinks, 9 and 10mm, 9mm is needed for this!  :headscratch:

20170910_123255 by Bjorn Bursell, on Flickr
« Last Edit: September 10, 2017, 03:08:13 PM by Bjorn_B »

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #12 on: September 12, 2017, 07:31:28 PM »
Micrometer collar day..

Nothing really unusual, with a 2mm pitch leadscrew, I i decided to do 40 divisions, just as the standard myford metric top slide but numbered for infeed rather than diametric numbers (myford collar numbering idea on the metric topslide makes so sense to me at all, it is numbered 0 to 35..)

Setup for scribing the collar
20170912_172314 by Bjorn Bursell, on Flickr

In progress. Long line every full mm (2 in total), intermediate lines every full 0,1mm and short lines 0,05, 0,15mm and so on
20170912_172319 by Bjorn Bursell, on Flickr

After lines are scribed, drilling, boring and reaming a half inch hole thru and some additional boring for a recess
20170912_180555 by Bjorn Bursell, on Flickr

Happy with the satin finish after using a scotch-brite type wheel on a airtool
20170912_181513 by Bjorn Bursell, on Flickr

Oh, there is a shallow recess inside the half-inch bore for the locking pad, after thinking a bit on how to do this with a lathe tool, i found a woodruff cutter that passed the bore, time for the Quick-step again!
20170912_183127 by Bjorn Bursell, on Flickr

Setup for stamping numbers
20170912_183344 by Bjorn Bursell, on Flickr

Numbering is half-descent at least..
20170912_190320 by Bjorn Bursell, on Flickr

After parting of, mounted on a small chuck and corrected for length, the radius was done with a hand graver
20170912_193620 by Bjorn Bursell, on Flickr

Done!
20170912_193749 by Bjorn Bursell, on Flickr

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #13 on: September 13, 2017, 05:51:44 PM »
As noted a few posts back, a 9mm countersink along with its mate has gone missing so todays task was to make a new 9mm one..

This book was dug out of the bookshelf..
20170913_183150 by Bjorn Bursell, on Flickr

And after intense studying, a piece of silver steel was massaged by the quick-step (yes it's featured again) after being turned to dimension
20170913_171623 by Bjorn Bursell, on Flickr
20170913_173303 by Bjorn Bursell, on Flickr
20170913_174152 by Bjorn Bursell, on Flickr

After some additional milling for the keyway, it was hardened and polished (somewhat)
20170913_181155 by Bjorn Bursell, on Flickr

And here is the new guy amongst the crew (yes, it is straight fluted...)
20170913_181145 by Bjorn Bursell, on Flickr

So, the gearcase now features countersunk holes!
20170913_183113 by Bjorn Bursell, on Flickr

Offline Bjorn_B

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Re: GhT geared and retracting top slide
« Reply #14 on: September 16, 2017, 09:01:09 PM »
Outline milling of gearcase parts today. As I don't have a good rotary table (but a sturdy dividing head) I chucked up a aluminium stump, faced of at both ends true and square. Drilled, bored and reamed a half inch hole in the centre and transfered this to the dividing head to use as a rotary table/milling fixture.

This is the aluminium chunk with the centering stump after all milling was done.
20170916_213942 by Bjorn Bursell, on Flickr

And this is one part of the gearcase being milled, the steel block was milled in this fashion too, but I forgot to take photos...
20170916_213856 by Bjorn Bursell, on Flickr