Bazmak-Making a turret/capstan for the minilathe

[bazmak]

I planned to make 6 locking pins from 12mm dia bar,one for each station
inserted from the bottom with a nut to pull up from the top.However I
realized the pins would clash with my locating ratchet on the u,side so
had to mount from the top with a nut clamping down.I also made only 3
each one clamping 2 stations.These will be locked/clamped tight while
I machine the 6 housings.
The housings will be nom 22 to 25 mm dia and can be machined in either
the lathe or the mill.I envisage centre drill and small step drill in the lathe
for accurate alignment the transfer to mill for more oomph.Final size will be
the boring head.Mine has an R8 spindle for the mill but would prefer to
finish in the lathe with light cuts.For that I will have to adapt to MT3
Will see how it pans out when I get there

 

[bazmak]

Well I pondered long and hard on the best way to machine the 6 stations
Fortunately I had the foresight to setup for both lathe and mill,thank goodness I did.The lathe was underpowered for the larger diameters and the rack feed
was too coarse.So I centre drilled and then stepped drilled to 12mm dia
which was the most accurate way for alignment to the headstock and station
locations.I then transferred to the mill to use 16,20 and 22mm endmills to
25mm deep and flat bottomed.Then set up mu boring head for its first
major use .Working well so far.Will make a couple of top hat tool holders
to use as a plug gauge to check the bores for size

 

[bazmak]

Turret stations bored out to 25mm.Made and fitted 2 no blank tool holders
Need to finish off the clamping gudgeon pins and then plan to make 2 no
ER 16 collet chucks,a die holder and a tapping chuck.May also drop back
to my second lathe thread,as the new handwheels and tailstock chuck have arrived.Hopefully the capstan will come straight off and the original carriage
and tailstock can just slide back on.Should only need to remove the leadscrew brkt and refit. Just 2 screws

 

[bazmak]

Tidied a few details up,made and fitted a locking handle and incorporated
another smaller pawl/ratchet to top of the turret and u/side of handle
Now when turret is locked the first 30o of the handle unlocks the turret
and a further 60o swings it round to the next station,and then back to lock
Works well,will show some video when I have made a few tool holders
and set them up with chucks etc.It will look prettier

 

[Wizard69]

Bazmark;

Looking really nice. Waiting on the video.

Im wondering about cross slide travel, it doesn't look like you have a lot there but that could be the pictures.

 

[bazmak]

Hi Wizard,there is no cross slide at 90o as such.The carriage and turret
stay fixed on lathe centreline. The dovetail cross slide is parallel with
the lathe axis and has a travel of nom 70mm.I made it for 2 reasons
To take up some of the height from bed to lathe centreline and to give me
some adjustment on tool extension.For instance if I have a MT2 centre
that projects say 50mm from the turret,but a Jacobs chuck with a long drill
projects say 120mm it will help with settings.(I hope but its all in my head)
until I fill the stations and start using it.As I said at the beginning its all
in my head and on the back of a cigarette packet
One thought that entered is that the compound slide will get in the way
so I have in mind to make a T slotted table to fit to the cross slide then
make front and rear toolposts for holding turning/parting off tools
It will all come out in the wash. Regards barry

 

[goldstar31]

Barry
Obviously, I cannot comment on the turret as 'mine' has yet to be tried let alone fitted!

However, I did the sub table thing some time back. I bought a 918 lathe or actually a 9180 which was one which would accept Myford chucks etc! The tee slots were 'the wrong way round to accept my collection of Myford tooling and I simply added a 28mm thick subtable without the slots and simply tapped it to receive such things as the George Thomas inverted rear parting tool, the vertical slide and the various rotary tables and dividing heads formerly on the previous lathe.

Really there was nothing revolutionary in it as Cleeve had fabricated a tee slot arrangement to use his lathe for milling. That was in Engineering in Miniature and the kit was sold by Blackgates Engineering. Chaddock of Quorn fame had two 'blocks', one of which was a bit orthodox whilst the other was simply peppered with holes and bolted or tapped ad nauseum. The latter was simply chucked away when filled with too many holes.

So others might find the foregoing sort of useful

Kind regards

Norm

 

[bazmak]

Norm,i know its nothing new.My sc4 lathe has a T slotted cross slide and great for moving the whole compound in and out.When the capstan is finished
with multi options for tooling I also need some tooling options for turning
and parting off etc.The best way will be to remove the compound (2 screws)
and make a sub table and front/rear tool post for turning etc.A bigger T slot
table seems to be the answer.2 options would be to make a new topslide or
a table to simply bolt on to the existing cross slide.Dont want to lose too much height,but having had a quick look I don't think I would be turning large diameters on this lathe with the capstan fitted.So will probably go for a bolt on table with shallow t slots to hold a front and rear tool post.Will probably go for
cast iron as its easier for machining the T slots.Maybe about 16 thick.This will allow turning nom 85mm dia max.I am also going to make a new leadscrew brkt at the tailstock end,then the entire capstan assy will just wind off without
having to take the brkt off.Lathe can then be used as std with compound and
tailstock Or the capstan assy wound on with tailstock removed and the table replacing the compound.Sounds easy and straightforward. I wish

 

[goldstar31]

Barry
I can see your logic! I confess to loving my rear tool post which has sort of been with me a long time- with great results.
When I changed from the Myford with its bull wheel which served as a dividing head( laugh!), I sort of was obliged to find another means of dividing- in the lathe. Hence the Hemingway rotary table and the Thomas Versatile Dividing Head had to have something to -- well, hang onto!


Digressing further( perhaps others will use it), I did a crafty interchangeability so that I could move things onto the mill or the lathe olr the Clarkson tool and cutter grinder and digressing even further, could get the Potts spindles in use or even swop the spindles and tooling from the Quorn, the Clarkson, the Kennet and my funny little fabricated Stent.

Perhaps someone will arrive in white coats and a strait jacket- but that is what I did.

Meanwhile- back at the ranch as our cousins would say, I got a daft little ML10 with a 65 tooth bull wheel which is not a fat lot of use as a dividing head but some earlier character had drilled a Burnerd Chuck with holes around the periphery.

Lateral thinking???

Regards

N

 

[bazmak]

Made 6 toolholders .Just finished screwcutting the 2 no ER16 collet chucks
Next is to cut the internal tapers.Also to cut the 2 no MT2 internal tapers
Awaiting for arrival from china of 2 no cheap 10mm Jacob type keyed chucks
which will be fitted to the other 2 stations then we are good to go. Video time

 

[bazmak]

Finish the 2 no ER16 collet chucks and the 2 no MT2 holders with 2 blanks
ready to fit 2 Jacobs chucks.Its starting to look quite professional
Its now easy to slip off the tailstock and slip on the tarret assy,no screws
Its also obvious that for use the compound needs to come off (2 screws)
and a T slot sub table to go on.Say 2 screws and next job.The best option
I feel is to mount the QCTP to the front and make a rear parting off tool post
A quick thought and then get some material.I have a piece of 100x20 ms flat
that would do,but am not confident my only,cheap chinese T slot cutter would be up to it so will buy a piece of cast iron nom 75x20 flat x 160 lg.A platform to the front to mount the qctp at the correct height and sq or round tool post
at the back for parting off.This should limit the interference to the turret and
can do multiple turning ops from the front with parting off the usually last op

 

[gunna]

I hadn't noticed before but in all your photos, South Aus seems to be one day ahead of the rest of the country.

Ian.

 

[goldstar31]

Greetings Barry! I'm having serious doubts about the possibility of cutting tee slots even in cast iron.
I'm not writing about heavy duty milling machines or such but on - in my case a, a reasonably powered mill drill. I was cutting the tee slots for a Stent in cast iron and the home made Myford tee slot cutter -------snapped. It's neck broke.
To be fair, a Stent 'top' is a series of runs all of 10" and I hadn't power feed then. Today, I would guess that with a power feed now that I would 'get away' with it.

Again, on the same job, I was cutting the long 10" vees- and knocked some teeth off my hss cutter.

It suggests that a power feed is desirable or a re-think and either fabricate or simply drill and tap holding down things!

Meantime, it's excellent reading for which I thank you

Norm

 

[hanermo3]

Fantastic thread and great work !

 

[bazmak]

Hi Norm,my thoughts exactly,great minds think alike. I fabricated a t Slot
table for my woodwork lathe mod and then reworked it to make an angle plate for the mill.I also fabricated a T slot faceplt for my first mini lathe and now
use it for my rotary table.They work great and I use them all the time BUT
I wanted something that looked a little more professional so have decided to
make one from solid.Not sure of the cutters capabilities so one option is to order a lump of cast iron.
I had bought a 1m offcut of 100x20 hrms and used most of it,when I checked
I had a piece left 170mm lg.Devine intervention I thought so will give it a go
If I knacker the cutter then all I have lost is $20 or so.Whats the point of keeping a brand new tool in the drawer because your unsure it will do the job
So I have made a start,Will try and rough out where I can with carbide then give it a go.Dont know if its HSS or Hcs but when I used a similar cutter the speed was too fast and it quickly took of the edge,so this time will take it slower with some cutting fluid.2 no dovetails approx. 7" long. Fingers crossed

 

[goldstar31]

Hi Barry
Thanks for the comments but I'm not in your league.

I'm hoping that your saga will create a spark or two with newer modellers.

One daft thought is that the top of the rotary table idea would go down well on a lathe plate. It might solve holding problems for lots of things.

Meanwhile, I await the next exiting instalment.

Regards

Norm

 

[bazmak]

Well afer all that worry and procrastination it was a piece of cake
The cutter did a good job and still kept its edge,but it was a long haul
The first slot took me about an hour but the second less than half that
The big problem was clearing the chips.They built up quickly fore and aft,cutting fluid made it worse changing the fine chips to one big clump
which quickly bound the tool and bogged down the mill.After a lot of the trial and error I found the best way was a very slow hand feed for about 5mm
then wind the cutter all the way out,and clean away all the chips.Add a little cutting oil and repeat.About 36 times per slot.Very happy with the result so far
next will be to finish it off and make a front and rear tool post

 

[bazmak]

The next part of the sub table was posted in the second lathe thread
so anyone following will have to flip between the two
Sorry but the 2 threads have converged,its difficult to say which is which

 

[bazmak]

All major parts have been made and fitted.Only tweaking etc to do
will take time with not a lot to show but will keep this thread going
I will post the video link from Utube below but have not had much success
lately.If you only get the link the will you please amend it as someone did
on the last couple of videos.Thanks barry https://youtu.be/4pfi53HNRY4

 

[Cogsy]

Here ya go Baz:
[ame]https://www.youtube.com/watch?v=4pfi53HNRY4&feature=youtu.be[/ame]