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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: Chuck fitting
17/07/2021 06:39:15

Another couple of options:

Machine the tops off the cap heads a little. The hex recess will be shallower, but you are not tightening them to three grunts.

Investigate low head cap screws. They are a legitimate product, but more costly than standard capscrews.

If you look at YouTube videos of Cutting Edge Engineering Australia, he has a line boring machine. The heads of the cap heads holding it together face the thing being bored. They are in through holes, so he has made a screwdriver slot at the 'tail' end so the hex key is only needed for the last 1/4 turn, a (potentially power) screwdriver being used for the rest of the movement. It would mean converting the female threaded holes in the chuck to through holes, but they could be of a small diameter to suit the screwdriver.

Gluing the spacers in the counterbores means you need one spacer per counterbore per chuck. Gluing the spacer onto the securing nut means you need only one per fastener. If used on a nut and stud, it has the same benefit as the unthreaded section of stud suggested above.

Thread: Harrison M300 siting
10/07/2021 15:16:17

In case you need it for dimensions, there is an M300 manual here:

http://vintagemachinery.org/pubs/detail.aspx?id=13849

With regard to removing the tailstock, a simple modification to the eccentric locking lever, so that it is retained by some other means than the grubscrew-in-a-groove (maybe drill and tap it on the side facing the user and use a countersunk bolt and washer) would allow vertical removal of the tailstock, removing the necessity to slide it off the end of the bed.

10/07/2021 11:07:44

Just as food for thought, and especially as access will be needed infrequently, perhaps have a good look at the machine and see if the 'operating mode' of the door and/or cover can be changed to suit the location.

I can only speak for a Chipmaster, but making the door hinge pins removable on that, so that it does not need to swing open 90 degrees for access has freed up a lot of space.

Thread: Universal thread cutting
05/07/2021 19:09:50
Posted by Andrew Johnston on 05/07/2021 09:53:08:

The value of 127 is indeed tied to the definition of metric and imperial conversion, but the fact that it is prime is no coincidence. It's the result of decomposing the conversion value into its prime factors.

I am not convinced of your reasoning.

Five inches is exactly 127mm. There is no need for factors there. The definition is what it is and just happens to land on a number which is prime.

In an alternative universe, we might have a definition of the inch where 5 inches equals 126mm. There, 126t change gears might be rather more common. There, the definition just happens to land on a number which is even, and thus not prime.

05/07/2021 06:16:11
Posted by Nigel Graham 2 on 04/07/2021 22:41:36:

...No need to search for prime-numbered wheels (though I did buy a 63T wheel)...

Could you kindly expand a little on how prime-numbered gears (63t not being one of them) might be of any use to someone?

If we start at 20t and stop at 127t, the primes are:

23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127

127t is used not because it is prime, but because it is fundamental to the definition of the inch as 25.4mm.

Of all the others in the list above, which might one even consider searchng for?

I can think of only two, 23t, for NPT threads and 113t which might be useful for the 355/113 approximation of pi.

04/07/2021 18:18:38

Yes. It has been done many times in the past.

John Stevenson and Brian Thompson's gear hobber was an early demonstration of the principle.

Look up 'electronic lead screw (ELS)'. This is an open source project.

On YouTube, the latest incarnation is by Clough42 (which has also been discussed on here in the past).

A VFD is not a servo.

For any indexing on a servo-driven (i.e. position-controlled) spindle, an integral brake is somewhat crucial.

Thread: Hofmann universal dividing head
04/07/2021 18:10:01

If you do a site-specific search of this site on Google, there are a number of threads that pop up. Perhaps a personal message to a fellow owner would get you the measurement you require.

The magic Google text (without the quote marks) is:

'hoffman site:model-engineer.co.uk'

Thread: SIP 14" Professional Bandsaw
01/07/2021 19:14:49

In case it helps anyone to help him, it appears that the 14" SIP bandsaw with the above number is a WOOD cutting bandsaw.

For reference: https://www.youtube.com/watch?v=qFjKMiu1P6c

https://www.dbkeighley.co.uk/masters/sip_01444_14_bandsaw.htm

----

Edit: it looks to be the same as the JET 14SFX model, for which there is a manual with wiring diagram here:

http://go.rockler.com/tech/Jet-14-inch-Bandsaw-manual.pdf

Reference pictures for comparison:

https://www.woodworkersjournal.com/jet-14-in-sfx-band-saw/

https://www.toolden.co.uk/power-tools/bandsaws/sip-01444-14-professional-heavy-duty-wood-bandsaw-1500w-230v/

Edited By DC31k on 01/07/2021 19:24:16

Thread: Is buying a custom ground tool my only option??
30/06/2021 19:08:07

SInce you mention 6mm dia. balls as a possibility, a standard RCMT06 insert would be a very cheap way to proceed.

Thread: Organising M.E. index spreadsheet
30/06/2021 12:57:07

https://support.microsoft.com/en-us/office/sort-data-in-a-table-77b781bf-5074-41b0-897a-dc37d4515f27

Your question starts at sub-section number 3.

Thread: Lead Screw cover/infringements Chinese Lathe
27/06/2021 10:22:51

It would be wise, before you skim the faceplate, just to confirm that the spindle nose itself is OK.

Take the faceplate off and run your indicator over the camlock spindle (face, external and internal tapers).

Once you are sure that is correct, then move on. Are you aware that with a camlock spindle, it is important to poke the same pin into the same hole every time for every item you attach to that spindle? If there is not a line scribed on the spindle for this purpose, it is good to add one.

Thread: Your assistance requested
26/06/2021 20:46:52

It is not unheard of for manufacturers to use the same diameter leadscrew on both their metric and imperial machines.

It makes manufacturing and stock-keeping a lot easier.

So it is possible to have 7/8" diameter with a 3mm pitch. Similarly, it is conceivable to have 22mm diameter with 8tpi cut on it.

The translation gear refers to the special gear or pair of gears that allow imperial threads to be cut on a metric machine or metric threads on an imperial machine.

Whichever are the native units of the machine, the geartrains for threads in those units will be simple (e.g. 20tpi on an 8tpi leadscrew needs something that simplifies to 5/2). For threads in the non-native units, the geartrains are more complicated and the numbers do not reduce to simple fractions.

Once you reassemble it, you can confirm the pitch of the leadscrew by measuring how much the carriage moves for say 16 revolutions of the leadscrew. It does not need sophisticated measuring equipment for this: a steel rule will distinguish between 48mm and 50.8mm and a chalk mark will index the rotation angle.

In case you did not find it, the actual manual for the machine is here:

https://www.manualslib.com/manual/1906935/Chester-Craftsman.html#manual

It worries me a little that you say the dials are in both units. If the exploded diagram in the manual is correct, then one set of dial graduations will, at best, be very difficult to use.

Dual reading dials that are easily-usable in both sets of units are available (best known is Gamet dials on Colchesters) but require a few more parts than are shown in the manual.

26/06/2021 10:07:45
Posted by larry phelan 1 on 26/06/2021 09:25:55:

...as far as I know it is 3mm pitch

Other aspects of the machine will provide strong clues as to whether it is native imperial or metric.

For instance, in what units are the dials (cross, top and tail) graduated?

What are the default thread pitches shown on the screwcutting chart?

Which language requires the translation gear to be used?

What does the leadscrew indicator look like?

26/06/2021 07:56:24

Not directly an answer to your question, but please have a look at this thread:

https://www.model-engineer.co.uk/forums/postings.asp?th=140535

It provides downloads to a manual and also some equivalent models sold with a different paint job.

Thread: Split cotters
24/06/2021 06:57:42
Posted by Michael Gilligan on 23/06/2021 21:39:01:
‘bored in-situ’ was my phrase.

A very appropriate phrase.

There is an article by Duplex in ME on these devices 29 December 1955 if anyone wishes to look further.

23/06/2021 17:47:06
Posted by Michael Gilligan on 23/06/2021 08:48:25:

Perhaps I am missing something, Derek … but I can’t see why the ‘offset’ should be particularly significant.

A different offset will produce a different angle on the cotter.

Consider the two extremes, where there is virtually no overlap between cotter and shaft and where the shaft and cotter overlap by nearly 50% of the cotter diameter (ignore, for the moment the clamping bolt).

In the first, the slope of the wedged sides will be very shallow. In the other, the slope of the wedged sides will be very steep.

With all tapers, there is a degree of slope below which they are self-holding and above which they are considered self-releasing.

So, I suspect that with a cotter, if there is too little overlap, it may not release when the clamping bolt is slackened.

Thread: calling 254 Myford owners
20/06/2021 19:18:09
Posted by John Haine on 20/06/2021 18:54:44:

Does the 254 have a large threaded nose like the big bore S7? Mine came with a big bore to standard nose adapter with MT2 taper if that would help?

See this recent thread:

https://www.model-engineer.co.uk/forums/postings.asp?th=173446

20/06/2021 19:17:44

How cheap is cheap? 4MT to 2MT bush is £10.96; Myford spindle nose on 2MT is £16.50, both from RDG.

Thread: Locking Bearing preload nut
20/06/2021 09:40:45
Posted by not done it yet on 20/06/2021 08:35:36:

Is there space for a jam-nut? KISS principle at work.

Jam nuts are difficult to use when setting preload. You always end up slightly rotating the one providing the preload, even though you are trying your hardest only to rotate the one doing the jamming.

A good engineering solution will separate providing the preload from providing the locking action.

The screw thread in question is a LH trapezoidal one, so the jam nut is unlikely to be found in the odds and ends bucket.

Thread: calling 254 Myford owners
20/06/2021 06:40:07

Myford spindle nose adaptors with 2MT are available.

Open-ended 4MT to 2MT reducers are available. In a different context, they might be known as a spindle nose bush.

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