By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for John Pace

Here is a list of all the postings John Pace has made in our forums. Click on a thread name to jump to the thread.

Thread: 3D Printing for Lost Wax Casting
16/04/2018 22:31:15


Seeing your casting with the lace curtain effect reminded me of a similar
problem that i had in the past casting some of these aluminium parts
seen here in the photo ,i had on some a granular net curtain appearance.
At about that time i attended the Farnbrough airshow ,the trade
stands there are interesting to see ,i showed one of the castings to
one of the exihibitors and suggested lowering the flask temperature
before casting the metal .It worked ,the differential for aluminium was
about 300 deg C.
Whilst 3d printing is an attractive method to produce prototype parts
any voids within are likely to cause problems when investing the parts,
some useful reading can be found at www.srs-ltd.co.uk\
navigating through the site shows some problems and likely causes
and remidies.Also to see how the process for mixing and investing
is carried out ,most of these investment powders have a strict method
that must be adhered to ie the mixing time vacuuming ,filling the flask
and vacuuming again .This is a one off deal ,i think that Neil's suggestion
of pre-coating the pattern will not work ,on a previous occasion i did not
mix enough investment to fill a flask and tried mixing some more to
fill the remainder ,it fell apart, the investment does not bond together.

Like all casting methods good patterns make good castings ,the
post by IanH using solid moulds using wax injection is the way to
go to get good casts .

The photo shows some cast aluminium parts looking closely it will
be seen that the inner parts of the moulds are polished ,when the
patterns are released from the mould the slightly translucent nature
of the wax can be viewed with the aid of a strong light to see any
voids of defects before investing.


Johnlost wax casting.jpg

Thread: Myford saddle oiler
14/02/2018 09:34:49


Hi Neil

I repositioned the rear oil nipple on the Myford when i converted
it to part cnc use as can be seen in the photo,the additional rear
bracket made it impossible to get access to the nipple.While the
saddle was off a small connecting holes were drilled through
from the diagonal slots on the underside of the saddle to link up
to the flat slide area of the crosslide ,small slots are machined in the
crosslide surface to allow the oil to spread a little .
When the machine is oiled some finds its way to the crosslide.
Perhaps a photo of what you have done,i have some similar oil
supply systems on other machines and they work very well.

John

myford 1.jpg

Thread: 1st lathe questions....
12/02/2018 10:41:08

I see from an earlier posting a suggestion was made about
buying a set from HPC gears ,looking at their listing
of gears to replace all 12 indicated in my later posting
at 2.5 module would be £722.29 inc the vat.

The bought gears at 30 mm wide would need to be reduced to
10mm wide to fit on the machine additional work would be
required to modify the hubs to suit the machine fixings.

RDG tools don't list 2.5 module cutters but do have 10 dp
which would do providing a full set of gears were to be
made would be satisfactory ,only cutters 3 and 4 would
be required to do the gears needed and at about £23 each
would seem to be an economic way to go.

The original gears are cast iron and 20 deg pressure
angle ,the RDG cutters are 14.5 deg pressure angle
As the gears would most likely be made in steel the
slightly thinner tooth profile would be still strong
enough.

08/02/2018 19:47:10

 

 

Hi Chris,

The Chester cub range is the same as the GH range of lathes
sold by Warco about 20 years ago ,i think they stopped selling
them about 2004.
Warco may be able to get a set of change wheels for this machine.
The wheels listed in the manual are 12 gears 27 to 30 tooth
33 to 36 tooth 38,41,43 and 45. They are 2.5 module.

I wrote an article in MEW 257 page 9 showing how to
make simple splined hubs for some 127 tooth conversion
gears.
The text mentions Fig1 showing these but it was missing
in the published article.
The two photo's here are from the article.

John

warco 2.jpgwarco 1.jpg

Edited By John Pace on 08/02/2018 20:06:23

Thread: Super High Speed Spur Gears
18/10/2017 12:45:53

Should have seen this earlier from my previous posting.

"Your electric motor at 4 kw approx 3 Hp the output torque is low at
0.315 lb/foot ".

Should have read.

Your electric motor at 4 kw approx 5.3 Hp the output torque is low at
0..563 lb/foot .

John

18/10/2017 11:37:13


Hi Joe,

The enclosed page is from a gear book and gives some advice on pitch line
speeds and types of lubrication .

Your electric motor at 4 kw approx 3 Hp the output torque is low at
0.315 lb/foot you could use some small pitch gearing somewhere
around 0.5 /0.6 module ,for example a 21 tooth gear at 0.5 mod at
5000 feet per min pitch line speed would be 46,200 rpm.
As you are only using the high speeds for short bursts you may get away with
exceeding the 5000 fpm by three + times .
It is just something that you will have to try.

John

gear speed.jpg

Thread: Embarking on a metal planer/shaper design+build
11/10/2017 18:11:20

Posted by
Davey J 11/10/2017 07:53:04

Might be worth checking the "Gingery shaper". The majority of which could be easily
constructed from sheet materials instead of castings That's where I am looking at the
moment. Book still available from various suppliers.

I would agree with this ,the Gingery book would be a good starting place for
any would be constructors of a home built shaper.
My own version of this follows a similar construction to the Gingery machine
but uses steel plate and cast iron block.Seen here all of this was made in 2013
and has sat in the corner of the shop ever since,runs at the moment on an old
washing machine motor .Designed from the start to be part cnc and manual
machine is an easier job then retro fitting an existing machine.
I may even finish it at some time.

John

shaper.jpg

Thread: (Tooling design help please) Die Cutting / Punching non ferrous sheet
22/08/2017 11:09:47

This piece of tooling i made about 20 years ago originally to punch
and form the holes in this gas turbine combustion chamber,since then it
it has been used for all sorts of sheet metal work.The original design
was from the Gas turbine builders association and was the work
of Terry Lee.
The 5.5 mm punch in the tray is exactly 5.5 mm diameter the hole in the die
is 5.65 mm diameter.
The punches and dies are silver steel .With a little imagination it would be
possible to accurately punch the holes and using an additional punch
and die to form a flange on the inner diameter as in your original photo
forming a greater contact area and providing automatic spacing of the
individual fins.
Drilling these holes is the least likely solution for a successful outcome
for obvious reasons.

John

punch set.jpg

Thread: Spinning Brass
22/07/2017 19:28:49

Hi Iain ,
Here is a better view of the spinning tool making something similar to
what you are doing ,material is stainless steel.
John
spinning.jpg

22/07/2017 19:04:33

Hi Iain,

Try annealing the brass before spinning,carefully heat all over to nearly red and

allow to cool.I use a wheel type of tool ,the one in the photo is about 4 inch in diameter.For inside edges

or sharp forms a mounted ballrace can be used as seen on right hand side.

faceplate.jpg

Thread: Chuck key missing?
16/07/2017 09:03:32

Hi Nige,

Keep digging you will find some more of these if you look,i have to say i was somewhat confused by the caption

on the photo bottom right on page 55 ,see top left page 54.

John

Thread: Feedback Sought - Beginner's Series
08/07/2017 09:27:32


Seeing this brings even more relevance to David Clark's recent thread " Model Engineers Workshop
Lost The Plot:"

It seems from Neil's later post ,
" I confess I am short of articles aimed at beginners.
Two pagers also really help me lay out the magazine!" that part of this is to fill up some pages.

As a long time subscriber to MEW i can remember some of the articles from the era when
Peter Rawlinson used to write in this magazine some really excellent works,the last
type of similar construction article seen in this mag was the stepperhead lathe and that
was when David Clark was editor ,i doubt if it was submitted now that it would be seen.


As ASF posted "Isnt there enough books and old magazines out in the public domain
to satisfy a beginner already?"

I would say there is more than enough ,the last thing that needs to be seen is some rehashed articles
as page fillers.
The clue is on the front of the magazine "Model Engineers' Workshop"
perhaps it would be a good idea to have some more substantial articles to appear in this
magazine again.

John


Thread: What type of Cast Iron is best suitable for dovetail slides
27/06/2017 21:02:36

Hi Joseph,

Have sent pm.

John

27/06/2017 17:43:17

shaper 3.jpgshaper 4.jpg
Hi Joe,

Something like this is fairly easy to make ,i used some old carbide 1/8 inch
cutter shanks ,drilled 12 holes at the appropriate angle then silver soldered the blanks
in place .the lands that keep the position are machined or ground away,then it is
just a matter of grinding the cutting edges.

Hss would probably be easier to grind than the carbide that i used .
The cutter head is bolted on to the 2 morse taper arbor.
The cutter is 41.5 mm diameter and 18.5 mm deep.

Used to cut the front dovetail seen here of this home built shaper.


Johnshaper 2.jpg

Thread: Overview of coolant use please
27/06/2017 14:26:55

oil1.jpgoil2.jpgHI choochoo baloo

The coolant system that you have listed is unlikely to be able to
pump neat cutting oil. I too bought from Axminster a coolant system
20 years ago which was similar to the one you have indicated and
tried to use with neat cutting oil , it failed and i sent it back .
I bought from them a better system that uses the more commonly
seen type of coolant pump seen here in the J&l advert and it worked.
To improve the flow rate the pipework mush be large enough to
place little restriction on the pump ,i use 15 mm copper tube and
the same bore plastic tube ,placement of the pump relative to the
work to keep the pipework of minimum length and keeping the
pumping head low will increase the flow rate.
I use neat cutting oil Excelcut 401 in 4 machines and Excelcut 433
in the Universal grinding machine ,they all use the same type of pump.
The J&L advantage adverts are from May last year but come around
often.
The sort of flow can be seen from this boring bar.

Johnoil delivery.jpg

Edited By John Pace on 27/06/2017 14:28:15

Thread: New Axminster surface plate?
25/06/2017 09:16:31

surface plate 3 points.jpg
The underside of your surface plate should still have
the three points marked on which it stood during manufacture
as in the photo .These marked places should be used to
mount the plate.Some of the better quality plates will come
with mounting pads fitted.

This plate came from Roto grip.

All of the answers you will need to know about your
plate can be found here

www.tru-stone.com/pages/faq.asp

The second photo shows this plate mounted,it is not
necessary to have the plate level unless your
application requires it,see question 12.

Johnstand.jpg

Thread: Help with lost wax casting
19/03/2017 09:25:50

Posted by

Richard Cox 18/03/2017 21:52:08
hi all

Im wondering if anyone can help I need to try and replicate this part does anyone know
how I can easily make a negative version to the make wax versions for the casting
process I've never done any lost wax before but my limited knowledge suggests as this
part is too complex to creative a negative simply, I suspect the original was die cast,.


In Mew 208 on page 8 Trevor Ford wrote an interesting article on die-casting aluminium,among
the parts made were track links similar to yours.

Some time ago i wrote some articles for Model engineer showing the lost wax
process and the equipment needed it was published sometime in 1993/4 .
The photo shows the cast wax patterns and moulds and some finished castings.

John

lost wax casting.jpg

Thread: Lathe line boring
12/03/2017 20:54:00

I use a method seen in MEW issue 168 page 56 by Ted Barclay in
which an amalgamation of a between centres boring bar and boring
head produces a very accurate result .
You can just see the Dore boring head revolving the boring bar articulates
when the cut is applied as the toolbit is halfway between the boring head
and the tailstock the graduations on the boring head dial are halved.

The deflection of the boring bar should not be much of problem ,when
boring like this on the crosslide you should ensure that the fixing of the
work to the crosslide is rigid enough and the clearance between the
saddle and the lathe bed is minimal.As can be seen in the photo the
work piece here forms a bridge between between the two supporting
parts ,the crosslide is locked during cutting.The clock gauge is left in place
during cutting to detect any movement.

John

boring bar.jpg

Thread: Drilling a parallel 1/2" hole
09/03/2017 11:37:49


To be able to drill straight and true through shafts this useful publication
from Camden books is worth looking at. "Making rifle barrels",it is about
drilling long straight holes ,some of it is about using gun drilling which would
probably be beyond the capability of most model engineers workshops but
there are sections giving advice on conventional drilling which result in
drilling straight holes.

I have used these methods for some of the examples shown here in the second photo.
The shaft seen here in the lathe is 8 5/8 inches long and drilled through
at 14 mm (.551 in) .Using 2 extended drills a smaller diameter pilot drill
has a bored hole formed to be a close fit at least 5x drill diameter and the hole
drilled at least another 8 to 10 x drill diameter ,the 14 mm drill size is also
bored a close fit and drilled to open the hole leaving at least 5 x depth
of the smaller diameter so the hole depth can be advanced.By changing drills
the hole is drilled right through.As can be seen in the photo a good supply of
neat cutting oil helps by cooling and lubricating and washing the drill and hole
of all swarf ,the drills should be withdrawn often to to clear the swarf and avoid
crowding the flutes.Two similar shafts were made one came out on centre the
other disappointingly was .002 inch off centre but probably within the accuracy
of the 3 jaw chuck. At full depth the hole is only 16 x the drill diameter.Using the
hole as the reference the shafts were re-centred and the finished from there.

The third photo shows one of 3 internal grinding spindles at 6 5/8 inches long
and drilled through at 7.3mm dia ,the hole depth is 22 x diameter .As can be seen
the shaft is held in the 4 jaw and supported by the fixed steady using a similar
sequence as previously the holes were drilled ,one as before was on true centre
the other .002 inch off ,the photo shows the last part of the sequence the shafts
having been referenced from the hole re-centred and rough turned to true up
to turn the 1 morse taper in the nose as in the photo .
The drills are sharpened as 4 facet drills ensuring the cutting edges are the same
each side.
The moral of the tale is if you start off with true hole the drill will most likely
follow it through.

John

straight hole1.jpgstaight hole 2.jpgstraight hole 3.jpg

Thread: Bought a Quorn, have som questions
13/02/2017 10:06:45

Posted by

Thomas Staubo 13/02/2017 08:07:16

It seems like you have 24 and 30 divisions. The 30 wheel must be for dividing into 5, 10, 15 and 30. Is that for special cutters, maybe like dovetail cutters?

It is just useful to have the facility to be able to divide these numbers.
I used the 24 division ring when making this dovetail cutter from some
scrap 1/8 inch carbide shanks.

John

shaper 3.jpg

shaper 4.jpg

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Meridienne; London MES
ChesterUK
cowbells
Ausee.com.au
TRANSWAVE Converters
Warco
Eccentric Engineering
Eccentric July 5 2018
emcomachinetools
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest