GhT geared and retracting top slide

[Bjorn_B]

Back at this again, got the leadscrew done today! It is a piece of commercial left hand 2mm pitch leadscrew that I got from accugroup (https://www.accu.co.uk/en/)

This was turned down at the end and loctited to a piece of bms. To make this true to the leadscrew I thought up this setup to drill with a centre driill at the end, running true with the axis of the leadscrew.
20171018_170226 by Bjorn Bursell, on Flickr

After that was done the piece was supported by the tailstock and about 50 mm of the outmost end turned concentric. The whole thing was then turned around and clocked up to run true in a four-yaw, end of leadscrew this time supported by the tailstock and the thread and o.d. was done. Result is shown here
20171018_190331 by Bjorn Bursell, on Flickr


 

[Bjorn_B]

Handle time:

Modified the stock top slide handle, GHT mentions setting it up in a four-yaw, I did not think this was feasible, but it really was super simple. My self centrering four-yaw seldom gets used, but for this it was perfect!

First a couple of passes with various drills
20171019_183255 by Bjorn Bursell, on Flickr

Then a bit of boring
20171019_183802 by Bjorn Bursell, on Flickr

After a final pass with a reamer this is the result, the top slide is locked and not useable until I'm done now..:
20171019_185434 by Bjorn Bursell, on Flickr

[Stuart]

Bjorn

we both have the same lathe and you have confused with your comment about the top slide dial as supplied you state it has 35 divisions , ok it is numbered to 35 but there are 5 more ticks to get back to 0 just the same as the cross slide



just had to check it out so 0 to 0 is 2 mm. 0 to 20 is 10mm


anyway nice work on the GHT project I have no made one Burt your idea of a commercial 2mm pitch screw has peeked my interest.


we spoke In one on your other thread about the dog clutch glad it works well mine certainly does oK but I used oil on for the two gears

Stuart

[Bjorn_B]

Hi Stuart!

Yes, I was a bit unclear about the topslide collar. The numbering is an issue for me, it is really numbered for diametric dimensions (0-40), but how would someone use this? The cross slide is in my view the main thing for diametric work and the top slide can't even be set at 90 to the bed because the handles would in the stock configuration clash anyway. The top slide is more for short tapers or threadcut infeed (both direct reading). I have now a direct reading (0-20) on the new collar that works better for me


Anyway, some small work today with the leadscrew nut (bought with the leadscrew), I Believe GhT mentined this was to be made on the faceplate, but a mill is so much easier. Bored out the hole and drilled the small holes in a piece of scrap brass I found. The top surface was then faced of to thickness.
20171020_175730 by Bjorn Bursell, on Flickr

I rough cut this on the bandsaw and silver soldered the thing together. Will be made to look nicer in a later stage.
20171020_182623 by Bjorn Bursell, on Flickr

[Stuart]

Thanks for the update Bjorn

I understand now your logic with the dial

its the same setup as the cross slide metal removed equals the dial setting

but I do use mine for diametrical work with it set to 90 deg. when I have the taper attachment connected and the cross slide un bolted

so its user choice I think I will leave mine as is

one point to think about while you play with the top slide . I have made a new one up ( kept  the old one just incase ) but I made it 1.5 mm thiner , my logic for this is I use the small Aa size multifix and my standard 10mm tools were a bit high now I have a bit of lee way ( it was the same problem with the Myford QC as you have ) I also offset the hole to the left by 5mm to give a bit less over hang .

I normally have the top slide over at approx 30 degrees so it suits my needs

keep up the good work always a pleasure to read and view your work

[Bjorn_B]

Been thinking of facing the whole top surface of my top slide of a bit, but a new piece could be made quite easy as you did! Would be really nice to be able to use 12mm toolholders... And a multifix would be nice too

Anyway, cleaned up the nut!

20171021_092242 by Bjorn Bursell, on Flickr

(counterbores are a bit oversize, I could not find anything to use in the correct size..)

20171021_100404 by Bjorn Bursell, on Flickr

The top casting of the top slide needs a bit more clearance for the feedscrew setting nut/slide bushing. So a ball end mill was put to use..

20171021_131416 by Bjorn Bursell, on Flickr

The rest of this days work is the locking screw and lock pins for the dial

20171021_104558 by Bjorn Bursell, on Flickr

Vice in a vice, I did not want to disturb the setting of the milling head to mill a 45 degree angle..
20171021_122502 by Bjorn Bursell, on Flickr

All parts are now in the small parts cleaner (cast iron dust here and there) I think I'll be able to assemble this tonight

[Bjorn_B]

I was a bit quick and had forgot to drill and tap holes for the backstop (used for tight internal threadcutting and boring jobs)

So Setting up on the mill again. This is at the end of the vertical capacity of my mill (my mill has no knee) so the setup as done with a myford type angle plate from the bed. An alternative would perhaps be to use the collet chuck to gain some Z height, but I'm a bit lazy..

20171021_172106 by Bjorn Bursell, on Flickr

Started assembly but i have a binding issue somewhere, need to sort that today.

[steamer]

Looking good Bjorn!

Dave

[Bjorn_B]

After finalizing the position of the excentric sleeve for the lever, The stop plate hole was drilled in the main body. The stop plate will be bandsawed/filed to shape later..

20171022_100135 by Bjorn Bursell, on Flickr

After fiddling about a bit, this is the top slide in forward position
20171022_102547 by Bjorn Bursell, on Flickr

And retracted:
20171022_102551 by Bjorn Bursell, on Flickr

Next interesting job is to set gear mesh, there is a excentric bushing for the primary shaft that is set in position in this picture
20171022_123351 by Bjorn Bursell, on Flickr

This is more or less the whole thing done, the stop plate needs to be made to shape yet.
20171022_124457 by Bjorn Bursell, on Flickr

Another shot
20171022_124511 by Bjorn Bursell, on Flickr

[Bjorn_B]

Could not resist, making the setscrew for the backstop (yes I have a die for this..)
It was a bit clumsy to do this one-handed 
Only the stop plate for the handle to do now 


[youtube1]https://youtu.be/oqe6QJD-TT4[/youtube1]

[sco]

Very nice work Bjorn!

Simon.