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Member postings for Brian Oldford

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

Thread: 63-tooth change wheel for Portass PD5
05/07/2020 09:14:19
Posted by DC31k on 04/07/2020 21:22:43:
Posted by Brian Oldford on 04/07/2020 20:04:34:
...whereas it's 94% for Mod 1.5.

Would you care to reconsider your suggestion of a metric gear specification in the light of the following, courtesy of lathes.co.uk:

"Portass lathes date from the very early 1920s and were first badged as being made in the west of Sheffield "?

For clarity, I have greater than 94% confidence that it is Sheffield, UK.

I know that a Portass lathe has imperial gears. I was simply reporting what that particular web site said.

04/07/2020 20:04:34
Posted by Rowan Sylvester-Bradley on 04/07/2020 18:16:22:

If I have measured/calculated this correctly DP is about 12 (a 65 tooth gear has an outer diameter of 106.8mm). What does CI mean for the Myford gear?.

Thanks - Rowan

For comparison Myford change gears are 20DP. According to **LINK** there's only a 75% confidence of it being 12 DP. whereas it's 94% for Mod 1.5.
The other important criteria id the pressure angle. Generally older gears tend to be 14.5° whereas more modern gears are mostly 20 °.

 

 

Edited By Brian Oldford on 04/07/2020 20:08:49

04/07/2020 18:08:28

Assuming it's an imperial gear, do you know the DP? Myford change-wheels are usually CI.

 

 

Edited By Brian Oldford on 04/07/2020 18:09:12

Thread: Part breakout /fixturing
03/07/2020 22:05:21

Use the third axis to leave a few small tabs to hold the piece in place.

Thread: Neil Hemingway Kits
03/07/2020 08:39:11
Posted by Nigel Graham 2 on 03/07/2020 00:37:37:

. . . . .

A point that puzzles me a bit about the 'Worden' Tool-grinder is why, having gone to the trouble and customer's expense of (probably CNC-) engraving a big, clear degrees arc on the table, they did not have the numbers engraved too. Instead the instructions tells you how to make a simple jig for stamping them, but that risks slightly uneven marking and worse, distorting the plate.

I would suggest manufacturing cost which would need to be passed on to the purchaser.

Thread: Tungsten carbide for shapers
03/07/2020 08:31:23
Posted by Nigel Graham 2 on 03/07/2020 01:30:01:

A point no-one has mentioned but Cornish Jack approaches, is one made in the old reference books.

It is that the edge of the tool should be under the clapper-box fulcrum.. . . . . . .

How can that be achieved when putting a key-way down a bore? I realise industry would use a broach nowadays but that's might spendy for a one-off.

Thread: Electronic Lead Screw Project
02/07/2020 10:33:01

Phil

As you may notice I have a few more things to do before I get to try this arrangement to work.

1: I have the key-way to cut.

2: Arrange to secure the bevel-gear to the lead-screw. (The grub-screw holes are there to secure the original bevel gear to the sleeve that fits around the lead-screw.)

3. Insert the remaining two screws that fix the stepper motor to the angle bracket.

01/07/2020 21:39:17

After being diverted onto other tasks (some from SWMBO and others such as collecting an alternative mill) and having a long ponder on the problem of stepper motors not taking too kindly to the end thrust from skew gears and following the advice of others I decided to replace the previous arrangement with 2:1 Bevel Gears.That in itself proved to be a bit of a task because the larger bevel gear being attached to the lead-screw required modification to fit and to be able to drive.
I now need to cut a key-way through the 5/8" hole to enable the gear to transmit power to the lead-screw.


Time to fire up the shaper.



gears 1.jpg

gears 2.jpg

Thread: Model Engineer Beam Engine - 9/16 Brass Ball Bearings
21/06/2020 13:09:34

Try here **LINK**

Thread: Weeds in a 'lawn'
21/06/2020 11:17:30

Get a couple of Labrador bitches. Their continual piddling will kill off most plants PDQ.

Thread: Perfecto 5 hand shaper
20/06/2020 19:17:36

Looking at those lovely swan-neck tools got me thinking.

Wouldn't it be possible to make a tool that relieves the cut if the bend of the swan-neck moved the cutting edge further back?

Thread: Jacobs morse taper chuck.
18/06/2020 13:52:01

+1 for folding wedges.

Thread: Hermes Parcels
16/06/2020 18:19:43

This morning Hermes notified me they had reimbursed my Paypal account for an item they managed to break whilst in their "care". Thankfully I had paid the additional amount to insure it fully.

Thread: Does it matter if tender valves pass a slight leak?
16/06/2020 18:11:00

Firemen on heritage railways usually get an ear-bashing from the inspector for wasting water if they do that.

Thread: Mild Steel Rod in Metric Sizes
15/06/2020 09:20:21

Lots of sellers on that well known auction site.

Thread: Electronic Lead Screw Project
15/06/2020 09:12:59

Many thanks Phil. I do like the control panel. £?

Thread: Brush motor repair
15/06/2020 09:11:45
Posted by Rod Renshaw on 14/06/2020 20:02:23:

Numatic HENRY ( or is there a Harry?)

That what I use as my shop vac. Great for getting the swarf from the nooks and cranies.

Thread: What Did You Do Today 2020
11/06/2020 20:24:37

Whilst waiting for parts to arrive for my Clough42 ELS I made the housings and fitted lead-screw thrust bearings.

 

bearing.jpg

As the new arrangement is somewhat longer I've had to "steal" back some space by: -
Reducing the plain bearing width
Shortening the boss of the lead-screw hand-wheel.
Re-drilling the lead-screw for the hand-wheel drive pin.
and
Shortening the Ny-lock nut so that the nylon engages with the thread on the end of the lead-screw.

Edited By Brian Oldford on 11/06/2020 20:26:47

Thread: Just right for the holidays.
09/06/2020 10:01:15

I shall defer purchase until August.

Thread: Cutting Oil
09/06/2020 09:49:42
Posted by Bo'sun on 09/06/2020 08:53:56:

Cutting oil and flood coolant are two different materials, and as I understand it, both perform a similar function. They keep the work and tool cool(ish), with flood coolant clearly working better. They also help to prevent material build-up on the face of the tool. Flood coolant is probably the way to go, but it can be messy, not all machines are suitable to accept a flood coolant system, and the coolant will need replacing periodically. Flood coolant can also make it difficult to see what's going on at the cutting face. Maybe a debatable question, but which products do people find work the best?

Isn't that the reason why some people are migrating to mist coolant/lubricant?

The inexpensive compressors that are now readily available make such a proposition quite viable.

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