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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: Screwcutting on the Bantam
27/05/2021 21:23:10

There is a thread here:

where, in the fourth post, a link is given to a very comprehensive data pack for the Bantam.

I am using page 16 (6 of 15 in the pdf) from that as a reference.

It gives a formula for threads not available from the gearbox: DRIVER/DRIVEN = (7 * Z )/(3 x Y * TPI)

Y is 1, 2 or 4. Z is 12 through 7.

If we pick Y = 1, Z = 9 and TPI = 27, the formula reduces to DRIVER/DRIVEN = 7/9.

There are only 18 possibilities with the formula so you can work through all of them to see if a better one emerges but I think the 7/9 above is the simplest.

Now the only gear you have with 9 in it is 36 (9 x 4), so the driver would need to be 7 x 4 = 28, which you do not have. 21/27 gives the correct ratio, but no 27t gear. 35/45 is correct, but no 45t. 42/54 is correct but no 54t. 49/63 is correct, but no 63t.

Any one of the missing gears above would solve the problem, so it gives you a few options if buying or making an additional one is a possibility.

27/05/2021 21:05:33
Posted by Tony Pratt 1 on 27/05/2021 20:49:37:

What idiot ‘designer’ would use 27 TPI?

There is a large country to the west of this little island, called the United States of America. The 27tpi thread is quite popular there on pipework.

Thread: Carriage stop/dial gauge mount.
27/05/2021 08:01:12

If you are going to have one 3D printed, consider incorporating a slot and clamping screw so you could then add a 'rain deflector' made of clear perspex, which would assist with the issue pointed out by Nigel above.

Thread: Incorrect thread pitch
27/05/2021 07:51:09

Is the machine a native metric machine? You say the leadscrew has a 6mm pitch: in what units are the cross- and top- slide dials graduated?

The reason I ask for confirmation is you state the thread dial has 16 teeth. For a native metric machine, a 16t gear on the thread dial indicator is generally not used or useful (as its teeth only have 2 or its multiples as a factor). Metric machines use _indicator_ gears with factors of 3, 5, 7 and 11.

In any case, since there are exactly three of your desired 2mm pitches in every 6mm of your claimed leadscrew pitch, you do not need an indicator at all for this thread. You can cover it up, ignore it, throw it in the bin and just engage the half nuts anywhere they drop in and the thread will be in synch.

If you have a link to an online version of the manual for the machine, please post it and we can look at it and advise.

Thread: Carriage stop/dial gauge mount.
26/05/2021 16:57:59
Posted by Danni Burns on 26/05/2021 12:54:39:

It would be good to find 50mm long reach clocks also. I can find 2".

Last time I went looking, Chronos (or maybe Linear Tools, their sister company) were sources for both languages of these.

You could always use a more standard 1" or 25mm travel indicator and a suitable 1" or 25mm spacer/gauge block/packer.

Thread: Any views on using Fairy Liquid in a concrete mix
24/05/2021 19:03:06
Posted by duncan webster on 24/05/2021 18:24:37:

There are approved plasticisers for mortar/concrete, and I'll bet they are not a lot more expensive.

Could you tell me where to buy Fairy Liquid for less then £3.00 for 5 litres please.

Thread: Strange result from the forum search ...
23/05/2021 08:57:48

Clicking on your link, the first post that appears is of a later date and time than the one below it.

Going to page 1 shows your post from today and page 899 is presumably your first post.

So I guess that as you put more posts in the 'front end', the page number of your older ones will increase. On the day Google's robot found the page, your post was on page 799.

It is not much help, but if the search points you to a particular page and the post is not there, at least you will know it has to be on a higher-numbered page.

Thread: That thread cutting dial thingy
22/05/2021 20:00:01

That indicator table is a triumph of marketing over engineering. They appear to have compiled it on the basis of more is better, regardless of whether any thread standard uses a particular pitch (e.g. 1.8mm or 2.4mm pitch) or any sensible person would cut a particular pitch (e.g. 7mm pitch on a 3mm leadscrew).

22/05/2021 17:40:12
Posted by Journeyman on 22/05/2021 16:18:19:

Have a look at my website covers this problem. Read the bit in blue then go down a bit to look at the ** Thread Dial Indicator ** hope it helps a bit.

On that page, you say, "Lesson 2, You can′t use the threading dial for all threads even if they are metric on a metric lathe."

As a general observation, not relevant to the problem in this thread, could I ask you to consider inserting somewhere before that a lesson 1 1/2, "there are a large number of (metric) threads that do not need a thread dial at all"? It is an aspect of screwcutting that is much under-written.

Thread: Help needed on Boring Bar insert.
21/05/2021 20:06:32

I offer this as pure speculation. Anyone who has better knowledge of the facts, please feel free to correct any inaccuracies...

As I understand it, the Komet brand has been swallowed up by Kenametal. A bit of research might find the date when this happened.

Is it possible that instead of a Wxxx insert, it might take a 'faceted triangle' insert? Please look at this eBay listing and assess whether the type of insert shown might fit in the pocket of the one you have:

19/05/2021 17:01:33

As I understand it, inserts are specified by their inscribed circle diameter, so that might be a way of arriving at a likely candidate. Make a peg of some known diameter that fits snugly in the hole for the securing screw. Make another cylinder that fits over this and keep reducing its diameter until it fits the insert pocket. Measure the resulting diameter and compare to standard insert charts.

Does the bar have a manufacturer's part number on it?

Thread: All things Beaver Mill
15/05/2021 10:39:17
Posted by Jonathan Deen on 14/05/2021 23:14:42:

Don't suppose anyone here could email me a pdf manual & parts diagrams?

Thread: Shortening HSS drills
15/05/2021 08:25:23
Posted by bernard towers on 14/05/2021 23:36:20:

Shortening jobber drills is OK for the odd job but they still flex as the shank is soft where the true stub drill is all hard

Could you please provide an explanation of how stiffness (which is a function of Young's modulus and geometry) correlates to hardness. Thanks.

Thread: D1-3 spindle nose adaptor
11/05/2021 08:20:03
Posted by Andy Pugh on 10/05/2021 22:55:39:

Looking (unsuccessfully) for a source of D1-3 cams I stumbled upon this thread.

A long time ago (10 years or so), JFK Precision in US listed all the fiddly bits for D-series spindles.

Thread: DTI contact points
08/05/2021 10:52:13

Check the thread pitch as Tracy's chart shows M2.5 coarse as 0.45mm pitch and M2.5 fine as 0.35mm pitch.

Have a look at:

(the diagram is especially useful. It would be good to see the pdf catalogue form which that comes).

You would need to buy 167 pieces to qualify for their free delivery though.

Edited By DC31k on 08/05/2021 11:02:02

Thread: Disposing of Gas Cylinders?
07/05/2021 17:43:36
Posted by ega on 07/05/2021 16:13:08:

Is that gas mixture - see Screwfix website - hotter than the ordinary Calor propane?

I believe propane is propane, so no. The torch that the gas bottle fits uses air at atmospheric pressure. If you want more hotness using propane as the fuel gas, I think you can use compressed air (like the Flamefast brazing hearths) or oxy-propane.

The same style of gas canister is available in a yellow colour and contains MAPP gas (also called MAP, MAP-X or MAP plus). Burning in air, this does produce a hotter flame.

07/05/2021 15:49:59

Your Screwfix link was fortuitous as one of the questions on the page is about a key, to remove the valve.

It is shown here:

Thread: Rothenberger Super Fire 2 Torch
07/05/2021 13:24:06
Posted by Jim Nic on 07/05/2021 12:53:02: the Bernzomatic to have the appearance of a Rothenburger by another name...

One could also say that the Rothenberger has the appearance of a Bernzomatic by another name.

If a person wanted to do some kind of due diligence on these things, it would probably be possible to find out who makes what for whom and to compare and contrast the warranty or replacement policies of the companies involved.

07/05/2021 10:59:22

If you are looking for similarity, please consider the Bernzomatic torches.

Thread: Can one buy pliers with parallel jaws that lock like mol
06/05/2021 07:34:50

There are very subtle distinctions in the mechanisms above. Some have parallel jaws; some have parallel action; one (the original photo) has, for want of a better term, perpendicular approach.

With parallel jaws, at any one point (i.e. when they are gripped onto the object), the jaws are parallel. As they move towards this point, the jaws may not move perpendicular to each other. All the ones above have this function.

With parallel action, the jaws stay parallel to each other while they are moving. The first one in the original post and the Stahlwille one have this function, as does anything with pivoting jaws.

With perpendicular approach, the jaws do not translate laterally as they close (so they are just like a vise). Only the first one does this.

Please consider the possibilities of these:

The adjustment screw on them means that the distance between the ends of the handles can always be the same no matter what thickness they are gripping. You would have to make a locking device, but that can be as simple as a loop of metal, similar to that used by blacksmiths for a tong lock.

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