Member postings for John P

Some spiral milling photos here 10 Tpi 1/2 inch diameter leadscrew finished length
about 20 inches , can be cut to full depth in a single pass , although i usually do a single
roughing pass and a second cut of about .010 " , rotation of work about 1 1/2 rpm.
Climb milling leaves a no burr finish, en8 is a good choice as it cuts clean and a
little stonger than free cutting steel.

Cutters seen here form relieved from silver steel on the Eureka device.

Useful for cutting worms , i use the cnc part of the machine for these odd pitches
as the pitch can easily be corrected to suit the chosen diameter, this one is 1 mod
for Vertex rotary table

John

I seem to have posted a link to some cutters that may have been of some use to you,

the posting seems to have vanished ? ,if you are interested in these send a PM and i will

PM the link back to you.

John

Edited By John Pace on 21/06/2021 10:53:08

Hi,
The photo's here shows the completely new head and spindle that
i made for my Dore Westbury mill when i cnc'd it ,there are three
speed ranges using 4 L type 3/8" belts and pulleys with the inverter
the speed range is from 100 rpm to 10,000 rpm .
Lot of work to do ,i doubt you would be able to fit something like
this on the standard Dore quill assembly.
John

I made a provision on my Warco milling machine to drive from
the lead screw to some form of spiraling head ,it never was used.
The cnc route turns out to be a much more useful method ,easier
to set up and to get the result that you need ,here are some that
i have done in the past.

John

Posted by Robert Butler 13/06/2021 18:30:25

I have just tried the set up with the the replacement imperial screw and nut but omitting the PX drive pinion
and the screw operates satisfactorily. With the pinion in place the screw is fine until pushing the nut the
final 1/8" or so into position. whether this is the nut or pinion which is having some effect and why is
unclear. The pinion and the exposed gear in the apron are undamaged as is the key which is an integral
part of the PX pinion and it slides freely on the screw.

Hi Robert,

It seems as if you are nearly there ,try fitting the power cross feed pinion with the
new nut but without the lead screw in place .
Disconnect the the lead screw drive from the lathe ,gearbox in a neutral position
or remove a change wheel ,engage the power cross feed and turn the lead screw
hand wheel whilst doing up the nut fixing screws and see if it binds up on the final
1/8 inch into position.

While you have the lead screw out check the depth of the drive slot and compare
it with the old metric lead screw....i can't remember how much clearance there is
around the lead screw in the bore of the drive pinion,but the lead screw should
be able to maintain a central position within the bore of the pinion without the
key bottoming out in the slot.

John

Hi Robert,

You could try and the new lead screw and nut without the power cross feed gear in place and see if you can adjust the new screw backlash and see if it will work satisfactorily .

The old metric screw is presumably 2 mm pitch and .500 inch diameter the same od as the new 10 tpi imperial screw , the part about " but when I did I had a cyclical issue with the screw or nut. " seems to suggest some problem with the internal key in the drive slot in the leadscrew.

Perhaps you will try this and let us know how you get on.

John

Hi Calum,
There is some useful viewing on the video of this page of
a similar machine to yours.

https://sites.google.com/site/lookatwhativegot/lathe-for-sale?tmpl=%2Fsystem%2Fapp%2Ftemplates%2Fprint%2F&showPrintDialog=1

I have a Warco GH1000 which is from the the same series of lathes.
I changed the oil in the headstock ,gearbox and apron soon after
i got it ,i used ep 80 gear oil from Halfords in the 20 years that i
have had the machine i runs as quiet now as when new both in
forwards and reverse.

I use neat cutting oil flood coolant (Excelcut 401) which is fortunate
as the coolant seems to find its way into the apron gearbox and fills
it to the top, bad if you wish to use suds coolant very probably it will
displace the oil in the box.
The occasional squirt of 68 grade slideway oil just from an oilcan
with bent spout is enough ,using neat cutting oil the slideways
are always covered in oil ,not the best oil for lubrication but there
is so much of it there the slideways are still as new.

Having two level pads for each end to stand on would be a good
start these machines have three bolting points at each end ,
in the centre at each end of the machine and each side on the
inner sides of the plinth ,providing they are level with each other
it will be a simple job to pack to get the machine cutting parallel.

I used the same method as described by Howard in the previous
posting ,it works.

The coolant tray on these machines are quite deep you may find
on the 630 machine it will have a slide out coolant tray which is
a useful thing.
When Warco delivered this machine it was on two small pallets
bolted down on the fixing points at each end of the machine
a long pallet truck picked up the machine , onto the tail lift then
around a much more tortuous route than you have over some
crazy paving pathway and straight into the workshop .
If you have a pallet truck available you may be able to do a similar
thing ,even a small one may do as your machine is 10 inches shorter
than my GH 1000.

John

Hi Michael,

Tyre fitters bonus.

John

Hi,

Sometimes i use modified caphead screws to enable a a low
profile type of fixing , this may work in the application in
securing your chuck as a draw bolt .
A 10 mm caphead screw is turned with a 10 deg taper
and the washer made after so the head of the screw
is level with the washer ,is a simple job to do and has a
8 mm allen key.

John

Hi,
If your lathe has a gear chart listing for module gears .3 mod has a
linear pitch of .0371" . 1 inch divided by 27 = .03703".

John

Hi ,

If it is the same address as this

Bearings Online
Warehouse Twenty Five
1 Kilspindie Road, Dunsinane Industrial Estate
Dundee, Scotland
DD2 3QH

I bought some bearings last year from them quick delivery good service and no problems.

John

Hi ,
I have a Warco GH1000 lathe they are the same as the Chester cub range there are some differences
mostly the layout and position of the apron handwheel and auto feed lever ,i would have thought that it
would fit through the gap of the existing door frame with the door on at the sizes you have indicated.
There would be little to be gained in removing the splashback as the electrical box mounted behind the
headstock protrudes 2 inches further out and the splashback follows the same line as the
stands and tray ,if you need to reduce the width both the apron handwheel and the crosslide
handwheel can easily be removed ,the crosslide bracket fits with two cap bolts and can then be
unscrewed from the crosslide as a complete assembly . Both of these project out most of all and
make up the width of 680 mm with them removed it would be about 580 mm .

John

Hi ,
You could try this for test cuts ,re-melt into blocks or sheets for test cuts,
if the machine is clean catch the wax swarf and re-melt again to reuse.
No blunted or broken cutters.

MOULD CASTING WAX 2KG FOR LOST WAX INVESTMENT CASTING

from

https://www.artisanfoundry.co.uk

Similar to this prototyping wax.

John

Hi Robin,
I've copied the whole of the illustration here and it shows the complete
sequence of operations , these copies come from a re-print of a book
from the 1920's and as such the working methods reflect that era , much
of this is still relevant in home workshops today ,with that in mind the shaft
depicted would most likely be hardened to run in plain bushings and need grinding ,the second
print here shows a similar shaft set up to have the internal taper ground using
this time belt lace to hold the shaft against the headstock centre.

The third photo here shows a similar set up using a sprung dog holding
the shaft on the headstock centre ,just for reference the springs have
about 15 to 20 lbs tension in each one.

No universal grinding machine about the only chance these day of owning
such a thing is to build it yourself ,unless you are lucky to find an old one
to restore ,don't think they are made these days.

John

Hi Robin,

Seeing your last post , this illustration may be of some use it is not
often seen now days but is a viable method to retain some concentricity.
They show this here as you have described reaming the internal morse
taper ,i would have thought that it would be wise at least to pre bore the
hole to as near morse taper form before using the reamer.
The sequence is much the same as you have described except for
the mounting in a 4 jaw chuck.

The set up is to turn between centres ,fit and adjust the fixed steady
whilst still held on centres,remove the tailstock away ,retain the
part on the headstock centre with the spring dog.

When you say the shaft is solid,is there no through hole ,if so how
do you eject the centre?

John

See this video for the explanation of positioning and coolant
flow,other videos is this series worth watching for other grinding
issues.

vimeo.com/196029009

John

Hi,

The two things that are important when making an internal morse taper are the
fit of the the taper and the axial alignment within the spindle ,step drilling
or boring and then reaming is less likely for this to be so .It is a simple
job to make a solid boring bar to cut these tapers ,the 2 here in the photo
are made just as morse taper for making 1 and 2 morse tapers but
undersize to allow the toolbit to protrude ,as such the boring bar will
be strong enough to not deflect and small enough to clear the small end.
When making these sort of spindles i find it easier to do the morse taper first
and use a double ended morse taper arbor and mount the job on this to cut
the outside parts of the spindle.
These days i leave enough in the taper to finish grind the taper mounted in
the spindle bearings , just because i can, seen here in the photo grinding
a 1 morse taper , the last 2 mt one that i had done was better than the
Myford 7 spindle nose and they are pretty good in any case.

John

Hi Baldric.

The Bridgeport is a substantial machine well suited to hobbing of these
gears ,the weak point will most probably be the rotary table side of things.
If you look at proper hobbing machines they are massive in comparison
to the items they produce ,at 14 Dp and 111 tooth count the minimum centre height
needed would be about 4.100 inches,the Vertex rotary and clones are 4.000 inches
from the centre to the vertical mounting base so would need to be on
a raised support ,the vertical mounting face is only 3.000x 6.000 inches by
comparison the fabricated hobbing unit that i have the base is 3/4 thick steel
9.000 x 8.000 inches in size.
The other end of your gear size range at 15 tooth ,with a 2.500 inch diameter cutter
you would be at about 150 rpm , with the Vertex table at 90 to 1 the stepper
motor input to the table at 1:1 would have to run at 900 rpm,i don't know
if that is possible ,my own hobbing unit has only a 5:1 reduction between
the stepper motor and the work shaft but i mainly cut small gears and have
hobs from 0.3 mod to 1.25 mod and 20 DP and sometimes cut as few as
5 teeth ,so at times the cutter speed could be around 400 rpm.
There is some more information on my own hobbing setup in
MEW 193.

Aliexpress have 14 DP hobs in 20 deg PA and 14.5 deg PA around
the £40 to £45 mark , both are 22 mm bore 50 mm long 55mm
diameter, Arc euro used to sell these but no more.

I think that it is fair to say that the hobbing unit you require would need to be
tailored very much to suit the type of gears that you would wish to make.
With cutters of about 2.500 inches in diameter the gear blank must stand
far enough forward to clear any rotating part of the rotary table and for the
cutter to cut past the face of the gear blank.From that point of view the
Vertex table would be a poor choice as the body depth is 2.000 inches
and the bearing surfaces are contained within this, a 4 inch chuck mounted
on the table would be a total of 4.000 inches away from the table body
add on the extra 1.250 to the gear blank for cutter clearance you have
5.250 inches overhang on a total supporting bearing contained
within 2.000 inches.
As for the Elliot 5" universal dividing head i have no knowledge of this
unit but you will be able to make your own decisions on this.

John

Posted by Baldric 30/04/2021 17:51:39
Has anyone done this using a Bridgeport, if so any tips on where to mount the sensor? I have an older step-pulley head, that I expect to run at it's lowest speed.

My rotary table has a 90:1 gearing, I appreciate this means the stepper will have to work harder, but I guess I can reduce the micro-stepping to compensate for that.

Thanks in advance,

Baldric.
---------------
Hi Baldric

You have not indicated what size DP or Mod gears you are intending to
cut ,the Bridgeport machine that is in your photo album seems to
show that the lower part of the spindle protrudes by about an inch
below the quill.
In my hobbing set up on a Warco A2f machine i use this part of the
spindle to attach a split collar turned in situ to mount a drive gear for an
optical encoder ,the encoder bracket clamps around the quill and is
seen here in the photo.
Above 18 dp the hobs are around 55mm dia and you may need a
substantial rotary table to cope with the cutting loads.
I only cut up to 1,25 mod or 20 dp as seen in the photo here ,the
set up here is much more rigid than any rotary table.
More photo's in the the album gears.

John

Hi Chris

Just make them to suit what you are doing ,paper in between the work and the table can be useful to protect an already finished surface.

John