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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: What are SILVER STREAK Wedges?
22/05/2022 11:28:21

22/05/2022 09:43:49

HSS: cutting something. Balanced: high speed rotation. Guess: spindle moulder.

Thread: Fix my (new) Lathe
20/05/2022 17:26:37
Posted by not done it yet on 20/05/2022 17:02:55:

JB’s seems OK with about ten times the clearance you have measured.

I wonder if the OP has his numbers mixed up. Do they make a 0.01mm feeler gauge? That is less than half a thou' in old money.

Thread: Operators manual
15/05/2022 16:06:37

It looks as if your machine belongs to the extended family of far-East machines such as those sold by Warco, Armadeal, Chester, Arc, Axminster, etc. They are also sold in the US by Jet and Grizzly.

In the US, they will be described as 'diameter of swing' x 'distance between centres', both in inches, so the equivalent of yours would be 9 x 24. The US manuals tend to be very comprehensive. So, rather than looking for a manual with the correct title, find a picture of a machine that looks identical and use its manual.

I think this is the machine in question, so someine who recognises it could tell you the UK- or US-equivalent:

Thread: Ball bearing cups for bicycle hubs ?
10/05/2022 07:18:01

Mike makes a very good point above about the contact of the balls with the cup. If there are two lines of contact, one generally on the flat part, the other generally on the side, that means the dimension and finish of the curved part of it does not matter at all as long as it is of no lesser radius than the balls.

Consider the other part that threads onto the spindle and contacts the balls. Have a look at its contact patch. Maybe the balls themselves are simply in three point contact (unequal - 90, 135, 135 degrees), all that is needed to resist combined axial and radial load.

Find an off the shelf one, paint it up with marking blue and operate it a few revolutions to see what touches what.

Thread: Colchester Triumph 2000 - Topslide Leadscrew Threadform
08/05/2022 11:40:15
Posted by Colin Heseltine on 08/05/2022 09:31:53:

Does not make it easy.

It made it very easy (and thus more economic) for Messers Box, Den and Col.

No need to keep two sizes of leadscrew blank in stock. No need for inventory management so they did not get mixed up. Similarly for the cutting tools. Simllarly for the workholding devices. Agile manfacturing ability - at the flip of a lever on the machine either language leadscrew is produced. No need to make a batch of 20 and then call the toolsetter to alter the machine.

In prodcution manufacturing, cost is an issue. Why do so many French cars have M7 threads? Because M6 is too small to work and M8 in million-volume is too costly.

It would be interesting to look at some of the European manufacturers' machines that were available in imperial form and see what they did (e.g Deckel & Aciera mills, Schaublin lathes). Also interesting would be to look at current far-East machines and see what they do - they sell into both SI and Inch markets.

08/05/2022 07:28:21

Make it 29 1/2 degrees and then calculate the maximum possible error in both cases. Chew on that number a bit in the context of every other error and uncertainty in the making process, including the wear.

Thread: Thread gears for Warco GH-1322 lathe.
05/05/2022 18:11:13
Posted by Howard Lewis on 05/05/2022 11:53:15:

Reverting to the original query.

In a very early reply to this thread, Jason posted a link to the manual for the machine. I am quite sure the OP can and will read it. It would be possible to save yourself an enormous amount of wasted typing if you read the same manual. Among other things, asking other people what the manual says would not be required.

As well as full details of the gearbox and change gear settings and physical arrangement, the posted manual contains details of the leadscrew indicator fitted to the machine, from which the pitch of the leadscrew can be calculated. Given also that the lathe is in a school, I do not believe the class will have a great deal of interest in imperial threads.

04/05/2022 18:53:07

The spirit of John Stevenson came upon me and reminded me what he did with his Bantam: he removed the change gears altogether and replaced with a toothed belt and pulleys.

On the machine in this thread, you would just have to measure the pulley centres and choose a combination of belt size and tooth count to suit that distance.

04/05/2022 13:14:55
Posted by Thor 🇳🇴 on 04/05/2022 10:33:23:

The 42-127-120-42 combination of gears you give in your first post is for metric threading...

If the standard chart on the machine gives the feeds in mm per revolution, that suggests to me that it a native metric machine.

Why would you need a 127 gear to do metric threads on a metric machine?

Looking in the manual that Jason linked to, the 127 gear is shown behind the 120 gear when metric threading, so is not in mesh with anything. In addition, the 120 gear is only an idler between the two 42t gears, so the ratio is 1:1.

So, if the OP only wants to cut metric threads, he absolutely will not need the four gears above. Depending on the physical layout of the lathe and adjustment possible on the banjo, it may be possible to buy just a single 32t gear and use the 100t as an idler. If not, a pair of gears of identical but larger tooth count would do.

Edit: look for a piece of software called GearDXF if you want to go the 3DP route.

Edited By DC31k on 04/05/2022 13:15:59

Thread: Reilang Oil Can Nozzle Thread
01/05/2022 16:05:23
Posted by KWIL on 01/05/2022 12:29:36:

Thread OD 4.4mm dia thread, 0.8mm pitch (using pitch guage) Hex on spout 6mm A/F

Would you care to speculate whether the tube has enough thickness of body to enable its internal thread to be enlarged to M5?

The male thread on the nozzle would be easy to enlarge.

01/05/2022 08:01:02

The smallest BSP thread is 1/16" with an OD of over 7mm, so it might not be in that series.

There is a picture of spare parts for one model of can here:

Please confirm it is the part bottom left of the picture.

Have you any known bolts that you can use as a thread gauge to judge the pitch? How have you determined it is coarser than 0.75mm pitch? What is the actual OD of the thread?

Cut the end off the delivery tube at the bottom of the internal threads and thread it a known, suitable internal thread (you are extending it, so just extend it 10mm more). Turn down the nozzle, soft solder on a plain sleeve and apply male threads to match the new internal ones.

Thread: Size of a Boxford metric Lead Screw
27/04/2022 11:07:03
Posted by Hopper on 27/04/2022 10:03:13:

But being metric, could it be a 30 degree Trapezoidal thread instead?

We have had discussions here before about metric leadscrews used on UK-manufacturered machines. Sadly, I cannot find one by searching, nor can I remember whether it was specific to Boxford or concerned another marque.

However, the consensus appeared to be that many of the manufacturers used imperial diameter stock and an ACME thread form for their leadscrews, just with a metric pitch.

It would be great if someone could find the thread just to refresh our memories.

Thread: Weird Collet Thread
27/04/2022 07:10:36

At the risk of over-egging the pudding, note that 10/12 pitch is 12 threads per centimetre; 15/12 is 8 threads per centimetre and 20/12 is 6 threads per centimetre. 1mm pitch is 10 threads per centimetre. Expressed in these terms, which are a close analogue of the way imperial threads are discussed, the pitches seem entirely reasonable and it is something like 1.5mm pitch that looks like an oddity.

Thread: Acme or not?
26/04/2022 19:06:00

If it is Swiss, is there a possiblity it could be metric, trapezoidal form? The dimensions are not so far off 14 x 3.5mm pitch.

How are you measuring the pitch? If you measure over 21 threads, do you get exactly 3 inches?

You would have to tell us what lathe it is in order for us to advise on gears.

Thread: What insert tool
26/04/2022 18:45:34
Posted by Dell on 26/04/2022 18:27:14:

...what about a chamfer tool holder ?

The CCMT insert is an 80/100 degree rhombus. Hence 'chamfering' can have two meanings. There is one on eBay that presents the insert 'straight ahead', which has the code SCMCN. That would give you a 40 degree chamfer. Glanze offer one that presents the insert at 45 degrees to achieve the conventional meaning of chamfer. Its code is SCSCR.

The codes you give are correct in principle. There is a 'C' missing from the right hand one (typo.). However, note that in a 10mm shank, the 'H' in the codes you wrote is the length of the holder (100mm). That is not so common in the smaller shank size, so you might have to change that letter to 'E' or 'F'.

Edit: the link you posted is perfect and also illustrates the shank length as 'E'.

Edited By DC31k on 26/04/2022 18:47:29

Edited By DC31k on 26/04/2022 18:50:30

Thread: Weird Collet Thread
26/04/2022 18:22:11

A curiosity of the W-series collet threads is that W10 is 10/12 mm pitch. W15 is 15/12 mm pitch and W20 is 20/12 mm pitch.

Against that, W12 is also 5/4 mm pitch, W25 is a true 15 tpi, and W31.75 is a true 20tpi.

See catalogue extract in post 2 here:

There is also a Schaublin product catalogue from 1946 on Scribd (stamped with Wickman Machine Tools) that shows their E-series collets, the precursor of ER collets.

Thread: What insert tool
26/04/2022 18:14:05

The important bit from the littlemachineshop page is this: ISO: CCMW060204 HSS

That is the International code for the insert. The other code, the ANSI one, is used mainly in the US, but they are complete equivalents.

The carbide equivalent of the HSS insert is CCMT060204, so any holder that will take this insert code will fit what you have.

ArcEuroTrade's own brand holders and the Sumitomo brand they also offer will fit.

This page is good for the holder codes:

You will need to look for something that goes SCxChyyz06 where x is the holder style, h is the hand of the holder, yy is the shank height and width and z the length. The other parts of the code are specific to the insert used, which you already have, and thus do not have a choice.

For instance, a standard, right hand turning and facing holder with a 16mm shank would be SCLCR1616H06

Thread: Alternative Ways of Retaining Shafts
26/04/2022 15:31:11

Drill, tap, thick washer with countersunk fastening.

Thread: Weird Collet Thread
26/04/2022 15:27:51

That's the trouble with keeping those nasty decimal points in your head.

Think in terms of fractions and you see that 0.833 is 5/6 (of 1mm).

The W20 thread is more commonly expressed as 1.667, or in fractions, 5/3.

Change gears do not come in decimals. They come in integers. And the ratio of two integers is a fraction.

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