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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: Tailstock turret
02/02/2021 12:30:07
Posted by ega on 02/02/2021 11:19:48:

I looked at your turret album. Your solution seems excellent for small diameter work, particularly if it could be combined with a five-way adjustable stop arrangement.

May I suggest an enhancement?

Right now, the length, design and position of the indexing plunger means the eccentric part of the turret has to be at the top or at the operator side of the tailstock.

If the plunger were rethought or relocated, the eccentric bit could be positioned towards the rear of the lathe, minimising potential for laceration.

Potentially, it could go perpendicular to its current axis. If it had a 45 degree end on it, pressing on a ball, the locking force can be made to turn the corner.

01/02/2021 19:20:16

I found a picture of it on AJ Reeves' site. It looks like only one part of it would need to change whether it had five or six stations. So perhaps keep your options open and buy two pieces of steel and make one of each number. While you are set up to make one, it is quicker to duplicate most of it than to start afresh if you only make one and it turns out to be the wrong one. If you use a 30-something when doing the dividing, it will cater for both.

Thread: Jacobs Chuck
01/02/2021 18:46:11

And run a file or stone around the snout to knock off any high spots before pushing it into the ring. Sometimes there are burrs there, especially around the three keyholes.

When you disassemble it, the nut will be in two pieces and look as if it is broken. It is made that way: in one piece with weak points and then split to facilitate assembly.

If you cannot find any visible cracks, and do not want to proceed straight to disassembly, make up a clamping collar to go around the ring, squeeze it up tight and see if the wheelspin disappears.

Possibly, you could repair it by drilling and tapping the outer ring for grubscrews. Rather than exerting pressure on the nut, which might not be a good idea, you might have to grind a dimple in the nut just so the grubscrew stops relative rotation of the two parts.

Thread: Bronze balls in place of steel balls in a Land Rover
31/01/2021 07:48:04

Rather than doing some kind of bush engineering on it, which is putting the cart before the horse, perhaps you should do some failure analysis first to inform your current situation.

How old is it? What service/lubrication/adjustment regime is recommended by LR? Has this regime been followed properly in the years since it was made? If you replace it as it was made and service it properly, what is its expected life? Is that expected life greater than your own?

Have a look at the range of available sizes for your proposed p-b balls. If it is being refurbished, will that be an additive process or a subtractive process? If the latter, slightly oversize balls, which are available in hardened steel may assist in tuning the steering to something slightly sharper than an oil tanker.

Thread: Metric thread sizes
30/01/2021 18:34:04
Posted by pgrbff on 30/01/2021 17:15:00:
...being in Italy with an Italian IP address my search results will be different to someone searching with a UK IP address.

This one any good?

https://www.bbpadova.it/viteria-e-bulloneria/barre-filettate/barra-filettata-passo-bsw-14010317/

30/01/2021 16:57:46
Posted by pgrbff on 30/01/2021 16:44:18:

I have been trying to find some high tensile 1/2 threaded bar in the UK and I haven't found any yet. It has rather a large 3 phase motor hanging off it and has bent.

If it has bent, it has been subject to bending forces.

Are you of the opinion that high tensile bar will resist bending forces better than low tensile bar?

The clue is is in the name. High tensile bar has a greater tensile strength than low tensile bar.

The ability of any structural member to resist bending forces is a function of its geometry and its Young's modulus.

Try:

https://www.grampianfasteners.com/product/653 (but shown as out of stock)

https://www.tfc.eu.com/product/high-tensile-threaded-rod-grade-en8-bsw/

https://www.ebay.co.uk/itm/BSW-Threaded-Bar-Screwed-Rod-Studding-S-C-Black-12-1-Foot-Long/191971076705 (admittedly, the grade is not shown, but it is hard to buy self-colour in anything but grade 8.8 so ask the seller).

Thread: Die query?
29/01/2021 09:52:15

Please have a read of these threads:

https://www.model-engineer.co.uk/forums/postings.asp?th=170639

https://www.model-engineer.co.uk/forums/postings.asp?th=170798

Thread: Milling machine enclosure
27/01/2021 18:45:21

As this is posted in the CNC sub-forum, can we assume it is a CNC machine that you wish to enclose (i.e. it will run unattended)?

I have something similar to this:

https://www.christowhome.co.uk/christow-large-reinforced-walk-in-greenhouse-1.html

with a CNC Taig mill inside it in a bedroom.

Cheap laminate flooring inside it, with the flaps of the greenhouse, shown folding outwards in the photo, folded inwards and under the floor. Henry inside for clean up.

Thread: Chester 836/Warco WM20 Lubrication Query?
27/01/2021 09:01:34

Like mini lathes, a lot of these machines differ only in their paint job and sticker name.

I have found that the US-supplied versions (JET, Grizzley, etc.) seem to have better manuals than our own.

Avail yourself of a list of likely manufacturers and then put 'xxx turret mill' into Google and look at images, where 'xxx' is the manufacturer name. That will help you find the model designation that manufacturer uses.

An original Bridgeport manual might also give you some pointers as the machines are close copies.

If you can find a suitable exploded diagram of the machine, that can help a lot with finding where to poke your oil gun.

Have a look at page 29. of this:

https://content.jettools.com/assets/manuals/690182_man_EN.pdf

Item 142 is the quill and it looks like half way up it is a drilling for an oil nipple, possibly for the lower spindle bearings.

If you lower the quill and smear with oil, it will come off the first time you retract the quill. Maybe lower it a little and introduce a thin oil from the top - it will be ground steel slowly sliding in cast iron so does not need much.

Thread: I need a Collet nut
26/01/2021 20:40:08
Posted by JasonB on 26/01/2021 19:59:39:

I doubt a German tool would have Whitworth threads, more likely Metric are you sure it's not M18 x 1.5

https://www.buvac.nl/wp-content/uploads/2019/09/HASPA.pdf

Page 8.

If I read it correctly, it is a strange one at M18.5 x 1.5. And you are correct. There is no collet in the world to fit that opening.

26/01/2021 17:35:52
Posted by Oldiron on 26/01/2021 16:33:18:

Would it be a major job to make your own nut. I presume you have the spindle so will have thread size & cone angle. Most other dimensions can be a compromise.

It might be good to look at the item about which he is talking - see Jason's link. It spins at 12,000 rpm.

For an item engineered to work in proper balance at that high speed, the £60 quoted above is a bargain.

Thread: Bridgeport power feed
26/01/2021 16:19:23

Yellow building site transformer.

Thread: Squareness gauge
26/01/2021 16:17:31
Posted by old mart on 26/01/2021 15:44:10:

...it could be checked at the desired top and bottom heights and adjusted to be true at those points.

You are correct, providing that squareness is needed to be checked in only one place. On YT, both OxTools and Stefan Gotteswinter have shown versions that do this.

On the other hand, if you need to sweep from top to bottom checking squareness, then the height gauge may not be good enough.

https://ecatalog.mitutoyo.com/Square-Master-Series-311-SquarenessStraightness-Instrument-C1825.aspx

https://www.kunz-precision.ch/en/products/squareness/SQUARE-check

Thread: How big Are Your Chips
26/01/2021 09:46:52

Posted by Ramon Wilson on 26/01/2021 08:32:16:

Nice one - but I'll bet if that came off a planer the work piece was correctly clamped down

I wonder if you can infer anything of the chip's origin from the hand of its spiral.

I am trying to visualise it. I think conventional turning on a lathe would make a right hand spiral.

What of shapers, planers and vertical lathes?

Thread: Motor reverse switch 3 phase
23/01/2021 10:43:50

If it has a truth table, you are halfway there. Use your continuity meter to translate into layman's terms what the truth table is telling you.

Martin has already told you all there is to know on the subject: to reverse, swap any two of the three phases.

In the off position, the three incoming connections, call them U, V, W, will not connect to anything at all.

In the forward position, U, V, W will make to A, B, C respectively.

In the reverse position, U, V, W will make to B, A, C (or similar).

It is very important for your own safety and peace of mind that you understand what is going on rather than just follow a recipe that says 'connect this to that'.

23/01/2021 09:26:31
Posted by Martin Connelly on 23/01/2021 09:10:54:

There are probably lots of wiring diagrams for dedicated switches but since the dedicated switches will be likely be just 2 or 3 positions (forward/reverse or forward/off/reverse) they will not help.

If we take the concept of a three phase reverse switch and the number '12', a good possibility is a fwd/off/rev/off cyclic mode of operation*. That would correspond to a 4 position switch in your terminology above so the diagrams for a 3-position one might at least give a starting point.

In the absence of a proper wiring diagram, use a continuity meter and make up a truth table for all terminals and all switch positions. Publish it here for review and we can tell you how to connect it.

Why not publish a link to the switch you have bought? Or if the source of your switch breaches the rules here, find an identical one from a 'clean' seller and point us in its direction.

* That is how the classic Santon ones work, even if the legend plate only has three marked positions.

Thread: BSF vs BSB threads
22/01/2021 22:00:01
Posted by duncan webster on 22/01/2021 21:29:20:

Even tho' the pitch is constant the helix angle will change with diameter, so do you really get away with just one set of thread rollers?

That is a very good question.

I went looking here:

https://www.threadtools.com/technical-information

and found

https://www.threadtools.com/uploads/pdf/technical-specs/alco-r-type-dimensions-capacities.pdf

If you look at the second page of the document, for BSP threads, the closest to a constant pitch easily to hand, the rolls only cover a limited range, so I think your observation on helix angle is well made.

Special mention of the technical info. page above as there is a lot of stuff there on Coventry die heads, particularly the sharpening thereof.

Thread: Running a 3phase at home
22/01/2021 19:17:28

Best tip I can give you is to write down two things: how much money you wish to spend and how much time you wish to spend.

If the first of these is a high number and the second a low number, the solution that works for you will be different to that if the first is low and the second is high.

Thread: Clarke collet chuck
21/01/2021 20:29:02

Have a look at post No. 16 here:

https://www.practicalmachinist.com/vb/general/newbie-what-type-collet-239158/

There, they are called Q24-16.

Life is very circular. That site also references this site:

https://www.model-engineer.co.uk/forums/postings.asp?th=102111&p=1

where the drawing above first appeared.

Thread: Princess Royal Oval buffers 3 1/2 H P Jackson
19/01/2021 12:55:40

I do not know if it is any help, but there seem to be some good photos of the class here:

https://www.railwaymagazine.co.uk/14567/from-the-archive-princess-in-waiting/

Also,

https://preservedbritishsteamlocomotives.com/8p-46200-46212-4-6-2-lms-stanier-princess-royal/

https://modelengineeringwebsite.com/Princess_Royal.html

https://collection.sciencemuseumgroup.org.uk/objects/co212771/model-steam-locomotive-princess-royal-model-locomotive

Perhaps send a suitable donation to these people and they will pootle off into their shed with a tape measure for you:

http://www.prclt.co.uk/

Edited By DC31k on 19/01/2021 12:57:47

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