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Member postings for DC31k

Here is a list of all the postings DC31k has made in our forums. Click on a thread name to jump to the thread.

Thread: Worm & Wormwheel Advice Please
11/11/2020 07:52:54

The challenges of making something fit an existing wheel, of unknown specification and unknown wear history are great.

What is so sacred about the old one? Machine the teeth off the old one and shrink or loctite or Dutch key a bored-out new one in their place. Fit a plain sleeve and cut new teeth into it if necessary.

If the worm is on the end of two universal joints, that might give some scope for altering centre distance (eccentric bush) and could open up the full gamut of gear manufacturer's catalogues, both in imperial and metric.

On measuring PA of spur gears: https://www.geartechnology.com/issues/0992x/janninck.pdf How and whether this applies to a worm wheel, I do not know.

Thread: Multifix toolholder Vendors
10/11/2020 08:43:43

Have a look at the info. on the lathes.co.uk website. There is a lot of the original Swiss Multifix literature there, including fully-dimensioned drawings which will inform your choice of size.

The best current seller of Multifix clones is not UK-based, so if I mention them here, it will invite moderation. Even with the VAT and duty and fees you will pay by buying from them (they will not attempt to sidestep the rules like many other overseas sellers), they are still cheaper and better quality than UK offerings.

Thread: Burnerd Multisize EC Collet Chuck - replacement KEY
09/11/2020 19:27:28

Some Burnerd dimensions possibly that might help:

Pilot 0.435"

Teeth 12

Big end 1.155"

Small end 0.880"

Tapered portion 0.485"

Thread: SDS. What is it?
07/11/2020 13:24:37
Posted by Michael Gilligan on 07/11/2020 12:47:19:

Curiously enough ... Wikipedia has a brief description, and useful diagram of the devious chuck arrangement:

**LINK**

In your travels, have you by chance ever seen a _specification_ for the SDS shank?

Right now, to make things to fit an SDS, I have to buy either a 1/2" UNF male threaded drill chuck adaptor or a 1/2" BSP male threaded core drill adaptor.

It would be good to be able to roll my own.

Thread: Harrison mill - metric lead screw form
06/11/2020 16:59:12

What pitch leadscrew did the IMPERIAL machine have?

I agree with Clive's assessment in that the original manufacturer would likely have just cut a metric pitch ACME thread on imperial stock. Even to the extent of using the same cutting tool. So rather than looking for the nearest ACME insert to your desired pitch, perhaps look for the same ACME insert that would have been used on the imperial leadscrews.

Thread: Boxford Industrial lathes
05/11/2020 17:20:08

This:

https://www.model-engineer.co.uk/forums/postings.asp?th=84252&p=1

is an important source of info. for these machines as it gives details of the centre spline in the changewheels.

Thread: Gear cutting company
30/10/2020 07:41:58
Posted by Michael Gilligan on 29/10/2020 20:34:20:

Sorry, Ian ... but I struggle to see that as 60 DP

It does look rather coarse for that. so I agree.

Just for reference, this page:

https://www.engineersedge.com/gear_pitch_chart.htm

gives 50.8 DP as having a circular pitch of approx. 1/16" and 64 DP as having roughly 1/20" CP. This would mean a 60 DP worm would need to be finer than 16 tpi and coarser than 20tpi, so a rough sanity check with a thread gauge will help a lot.

Thread: Colchester Bantam MK1 Milling Attachment Query
26/10/2020 18:52:35

When you say 'Myford type milling attachment', do you mean a simple vertical slide or more like a Rodney?

If a generic vertical slide, a simple adaptor plate that bolts onto the cross slide using some of the many tapped holes Colchester provide (UNC threads) and having fixing provision for whatever design of vertical slide on its top face would do well.

If a genuine Myford, perhaps a Myford cross slide from a breaker could be thinned down and drilled to suit.

Thread: CVA 1A series 3 travelling steady
26/10/2020 09:16:55

It would be unworkable to have tapped holes in the cross-slide for a travelling steady as it would be difficult to centre when setting up and would change position every time you put on a cut.

The mounting points will be in the saddle of the machine.

As David says, look on the lathes site: the one picture there that shows the travelling steady has it bolted to the tailstock side of the saddle - it spans over the cross slide.

Maybe also look at pictures of the Monarch 10ee for guidance as the CVA has some similarities to that machine.

Thread: Turning and boring almost any* shape. *within reason
23/10/2020 08:27:59

A couple of questions:

Right now, it is effectively converting a closed shape into a series of (X, A) coordinate values, where I guess the A- increment can be arbitrarily small.

How easy would it be to make it turn 90 degrees and produce (Z, A) values? I am thinking of a face cam, as used in Brierley and Rush drill grinders.

https://rushmachinery.com/products/drill-and-tool-grinders/model-132c/

Second, does it have any built-in idiot-proofing? If I sent it a circular hole with a keyway cut out, would it tell me to go away and pound sand due to the discontinuity in the profile? As a corollary to this, what is the most acute internal angle with which it is comfortable (e.g. an equilateral triangle-shaped bore)?

Thanks.

Thread: Measuring pitch diameter of clock wheel
10/10/2020 19:49:22

Let me start by saying I know nothing about cycloidal gears.

However, I have some familiarity with involute gears. In the involute system, pitch diameter is never measured directly. It is a number that is derived from other measurements of the gear (you measure the outside diameter of the gear and count the number of teeth - the pitch diameter falls out of manipulating these two numbers).

If you are measuring from the bottom of the tooth space, you have a good chance of being incorrect as the dedendum may incorporate clearance.

This page seems to me, a complete beginner on cycloidal gears, as good a reference as any and contains a number of subsequent references:

https://www.csparks.com/watchmaking/CycloidalGears/index.jxl

Thread: FC3 'disposable' cutters in ER Collet?
10/10/2020 11:08:31
Posted by Ian P on 09/10/2020 20:53:45:

Some of my ER25 collets (a mixture of cheap Asian and some quality European ones) have bores like your example but there does not seem to be a particular diameter value where the bore changes between the two types....

The diameter at which the collet is relieved also varies with the ER-series number.

For as close to gospel as you might easily obtain, have a look at Regofix' site as I believe they have dimensioned drawings.

For slimline, have you considered changing the closing nut? There are generally two types: the one with spanner flats or hex. and the type with a pronged spanner.

You could also buy an ER11 or 16 chuck on a straight shank and hold it in your ER25 chuck for reduced girth but increased length.

Thread: How do I disassemble Vickers dual metric/imperial dial?
07/10/2020 07:46:42
Posted by Oily Rag on 07/10/2020 00:03:05:

...the clever bit from memory was that they were identical tooth wheels but of slightly differing diametral pitch so giving a differential gearing.

I think your memory is perhaps deceiving you.

If the tooth wheels are identical, how is the imperial to metric conversion done?

In the Gamet ones, fitted to Colchester lathes, the two internal gears have different tooth counts (125 and 127), but cut on the same pitch circle so they mesh with a common planet pinion gear.

FWIW, the Gamet patents are available online, with patent-style exploded diagrams so this may give some insight into how the OP's one could work.

Also FWIW, it seems that Vickers offered these dials for Bridgeport mills, so some searching around this area might assist.

E.g. https://www.ebay.co.uk/itm/Bridgeport-mill-dual-dial-conversion-250-6mm-new-old-stock-imperial-metric-/233580651017

https://www.ebay.co.uk/itm/Bridgeport-mill-dual-dial-conversion-200-5mm-new-old-stock-imperial-metric-/233580652006

Thread: Horizontal Milling Attachments
05/10/2020 18:52:42
Posted by Nigel McBurney 1 on 05/10/2020 18:07:07:

...also attachments such as these are not that rigid.

Could you please expand a little on this statement.

At one end it is clamped to the ram dovetails so the ram does the same job as the overarm on a horizontal machine; at the other it has a death grip on a large diameter quill.

05/10/2020 14:32:48

A picture or a link to a picture of a Warco Economy would be useful.

All I could find was something that said it is the same machine as a ZX25.

A link to the Chronos offering would also help. Is it this: https://www.chronos.ltd.uk/product/sct-horizontal-milling-attachment-r8/ ?

Rotagrip will also sell one so it is worth looking for info., prices and pictures there also. Somewhere on their site, they have the full Vertex catalogue for download.

The attachment is designed for Bridgeport-style turret mills with a ram. You extend the ram and clamp the arbor support to the dovetails on the underside of the ram.

I think you may face considerable challenges in making this device work on your machine.

Thread: Martin Cleeve Swing Clear Retracting Toolholder
03/10/2020 21:35:20
Posted by Michael Gilligan on 03/10/2020 20:45:49:

Try here, Roger ... I re-posted the link earlier today

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=168193&p=2

MichaelG.

This is another old post of yours linking to his patent:

https://www.model-engineer.co.uk/forums/postings.asp?th=139985

Thread: ER 40 Milling nose
26/09/2020 18:47:47

Have you considered how you will hold Morse tooling in the new spindle arrangement, particularly drill bits?

I have never drawn it up, but what size Morse taper would fit within the confines of the ER40 collet cavity?

Thread: Brierley ZB21
22/09/2020 07:32:40

There is also a ZB25 manual available at a price much more commensurate with its quality on eBay. The seller is fazerblazer and full seller contact details can be seen without logging in - Premier Machine Tools in Nottingham.

As for the cams, they are fairly easy to duplicate if you can find someone who has one to copy. Just put on a rotary table and map the rise every couple of degrees of rotation.

Find someone with a CNC machine with an A-axis and a touch probe and the mapping could be done almost automatically.

21/09/2020 21:56:18

AFAIK, the 21, 25 and 32 in the model name referred to the biggest tool that would fit through the spindle. In most other respects, the machines were the same, so a manual for any will do.

Tony at lathes.co.uk sells badly-photocopied incomplete manuals with thumbprints and distorted pages but on very good heavyweight paper.

You could look at this:

https://www.youtube.com/watch?v=aLPZcvb1zwk

or look here:

https://passion-usinages.forumgratuit.org/t1213-brierley-clarkson-affuteuse-de-forets

Thread: Stuck SDS drill bit
20/09/2020 21:01:44

The diagram in the article to which Michael links is very useful:

(https://en.wikipedia.org/wiki/Chuck_(engineering)#/media/Filepecial-Direct-System-chuck.png)

The (normally rubber-like) end cap, not numbered in the diagram, but cut through by the upper and lower II section arrows, should just prise off. This will allow access to the collar that retains the balls.

As he says, a good clean and lubricate should solve your problem and endcap removal will allow you to check that the collar is retracting properly. The balls have to come out from the outside or they would fall into the chuck every time you remove the bit.

I have only seen it once before, and I hope it is not the issue here, but I once had an SDS drill bit that was improperly heat treated such that the hammering action mushroomed the end of it within the chuck. This made it very difficult to remove.

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