Member postings for DC31k

To amplify Jason's point, for _any_ thread series (ISO metric, UN, Whitworth, BSCy, PG)* where a particular pitch is used on more than one diameter (so, really anything except BA), the depth of thread is only related to pitch and form (geometry).

In particular, it is independent of diameter. You can cut 1mm pitch on 6mm diameter or on 50mm diameter. The amount you plunge in is the same.

The only place diameter has an influence is when calculating helix angle, which determines the clearance angles required on the cutting tool (the M6 x 1.0 will have a much steeper helix to M50 x 1.0) .

* ISO metric and UN use identical forms, so really this is a list of four possiblities, not five.

Rotagrip list one. The link is incomprehensible, so search for:

'slitting saw arbor 30 int rotagrip'

Why do you need a special arbor for slitting saws? Do they not fit on the standard horizontal arbor? Or is it for use with the vertical head?

This might be a good place to start:

https://www.rdgtools.co.uk/acatalog/30-INTERNATIONAL-TO-1--FACE-MILL-ARBOUR-1040.html

It has a 1" spigot, that will suit many slitting saws. It has a key in it whch can be adapted or discarded. Remove and discard the drive dogs. All you need to make is a cap and some spacers (or buy the spacers or borrow them off the horizontal arbor).

You could buy a plain shank slitting saw arbor and mount it in a 30 taper ER32 collet chuck. Lots more bang for your buck that way. You can similarly make a 'plug in' full horizontal arbor to suit the ER32 chuck.

As supplied from Warco, the machine will expect 415v three phase input. In other words, you put a red four or five pin socket on the cable and plug it in. At this stage, we do not know if it needs the neutral supply of the three phase.

Every part of the machine downsteam of the red plug will use the supply it provides. That includes all the control circuitry (E-stop, chuck guard switches, rear cover switch etc.), the light, the suds pump and maybe the DRO if fitted (Warco's site is not clear on if the DRO requires a separate supply or is supplied off the lathe).

The description for the machine says it already has a jog function so there is some unknown electronic wizardry going on there.

You do not say what type of VFD you wish to fit - one that takes 415v three phase input or one that takes 230v single phase input.

Everything is possible but to fit a VFD you will end up removing every part of the lathe that relates to its electric system and re-doing it. That might invalidate the warranty.

The closest I have seen to that is the Trend router lathe, used for making spirals on sticks. I think Sears Craftsman in the US also made one (Router Crafter 720.25250) and manuals can be found at vintagemachinery

If it is clearly a drain point, meant for coolant, the most likely thread is that used in conjunction with pipework, i.e. BSP.

M20 x 1.5 is a standard thread on electrical conduit, which generally is not used to carry liquids. That thread would be found on an electric motor, for a cable gland in the same way that a BSP thread would not be found on a motor.

M20 x 1.75 is extremely unlikly as 1.75mm pitch is not used anywhere in metric threads other than standard M12 coarse.

What I am saying is that the purpose of the thread can be a good pointer to its specification.

I stumbled across these tonight and they are quite close in concept, if not size, to what the OP wanted two years ago.

A bit of diligent searching might find an ER32 one:

https://www.ebay.co.uk/itm/394745604793

Edit: sure anough, a bloke called Ali will send them to you by Express delivery.

The key search term is "transfer head adapter transition joint" £25.68 as of this date onto your UK doorstep for ER32 to ER32.

Edited By DC31k on 20/08/2023 21:57:30

I might be misunderstanding you here, but I do not think that would work.

The typical 50mm boring head has two vertical holes in it for the tools. One of those holes would have to be set (adjusted) concentric with the boring head's axis of rotation in order for it to be used to house a co-axial indicator (or even a standard edge finder).

You could use a standard lever DTI in the manner you describe but not something where the dial always faces you and the mechanism rotates.

When you use the point of the tool to find centre as you describe above, it is always a constant distance from the rotation axis.

There are lots of Myford workshop manuals available for download from here:

http://vintagemachinery.org/mfgindex/detail.aspx?id=4654&tab=3

A potential advantage of the co-ax indicator types used in a hole compared to a standard edge finder is that they will work at zero rpm. You can turn the spindle gently using one hand and see how the needle moves (even rotating it in discrete 90 degree increments if necessary). With an edge finder, it needs some powered rpm to see the wobble disappear and then observe the 'kick'.

With a co-ax indicator, finding centre is quite a smooth single operation. Poke in the hole and adjust until the needle does not move and zero everything. With an edge finder, there are four (maybe six) distinct actions that have to be coordinated with DRO button pressing.

Where a co-ax indicator might score is adjusting the height of a dividing head tailstock especially if you are setting it up to cut a taper.

Could we come up with something a co-ax can do that a standard indicator and a mirror cannot do?

You did.

https://www.model-engineer.co.uk/forums/postings.asp?th=118853

Bypass the thread conundrum entirely and Loctite the shaft extension on.

From the seller's pictures, I guess you are using it in a lawnmower or an abrasive chop saw. Those eBay Watts sure have increased in size since I was at school. Quite the opposite to a packet of polos.

See:

https://www.tools-n-gizmos.com/specs/Tapers.html

https://www.cutwel.co.uk/blog/differences-between-bt-sk-iso-psc-hsk.html

https://en.wikipedia.org/wiki/Machine_taper#NMTB_taper_family

https://www.scribd.com/document/485098700/Machinery-Handbook-Standard-Tapers

https://cdn.standards.iteh.ai/samples/4226/0e63bb1e284e4782981af8c6506ed54f/ISO-297-1988.pdf

I do not think there is a formal standard for INT40 or its various synonyms (40 INT, 40 International).

The grand daddy of them all is the US NMTB. All others are derivations of that. You will notice in ISO297, UNC drawbar threads are permitted as an alternative to metric.

If the switch is mounted on the axle, how does it transfer electricity? Last time I looked, there were no brushes or slip rings in my lathe motor.

The switch is fixed to the bell end of the motor. It is the weights that rotate.

----

Rather than pulling the motor off and to pieces, slip off the drive belt and see if you can reproduce the problem. If the motor fails to start, mark the pulley position relative to a fixed point and see if the position theory (bad spot) holds up. Given that the drive:driven pulley ratio is unlikely to be 1:1 you will then have separated any spindle issue from any motor issue.

This is an idea for a tool as the one pictured would not fit (or maybe it would if you removed the pin and reattached once in the hole):

https://www.zoro.co.uk/shop/cutting-tools/combined-drill-and-countersinks/rc2000-medium-reversible-countersink/p/ZT1126465X

I wondered what the UN and Whitworth thread series equivalents to ISO2857 (also called EN22857) might be.

Some info. (but not a formal standard) here:

http://www.tapmatic.com/tapping_questions_class_of_threads_h_limits.ydev

Note that the number after the H is the multiple of 0.0005" that the pitch diameter is oversize for that class of tap.

This puts it a little more clearly (but note that the link below is for an STI tap, so ignore the actual numerical values):

https://katofastening.com/article/taplimits.html

Best I can find for Whitworth form is ISO5969, which is for ISO pipe threads (which are Whitworth form).

https://cdn.standards.iteh.ai/samples/12163/1c8129d4e26a45a9a5452ae960f61f91/ISO-5969-1979.pdf

Thanks for the reply. There is some shorthand going on in Sandvik's descriptions.

ISO limits and fits (e.g. https://simplybearings.co.uk/shop/Info-Pages-ISO-Limits/c4746_4779/index.html?page=1) are fussy about nomenclature, hence my confusion.

Any tolerance with uppercase is for a hole rather than a shaft, so in a very strict sense a 6H tap is non-sensical. The short hand translates to 'a tap designated 6H will produce a female thread to 6H tolerance'.

Thanks to some words from the link you kindly provided, I found ISO2857:

https://cdn.standards.iteh.ai/samples/7858/fb4ec4f1d31d4e02b38f44d39c4bd111/ISO-2857-1973.pdf

So, as you say, use the dimensions from ISO2857 and perform the three wire calculations on the basis of these.

Probably best to do all the measurements before cutting three flutes into the tap.

Having just watched a YT video by Artisan Makes, he is making an M20 x 1 tap.

In the video, he states that there are online calculators for three wire thread measurements. So far, so good.

But if you are making a tap, does it not have to be larger than the bolt that screws into the female thread that the tap produces?

So how do you arrive at the correct three wire measurement for a TAP?

There is some information from Sandvik on the class of thread produced by a standard tap here:

https://www.sandvik.coromant.com/en-gb/knowledge/threading/tapping/thread-standards-and-thread-tapping-tolerance-classes

and it quotes H6 as a typical female thread tolerance.

What would be the shaft tolerance on the tap to produce this hole?

No three wire calculator I can find alllows an oversize tolerance.

Thanks.

The unscrew-one-turn-and-measure idea is good. Because the arbor is flanged, a set of feeler gauges might work very well for this pirpose.

A 5/16 BSW bolt could be used if your thread gauge does not have 18tpi on it.

You could also go for a majority decision: try to find an 1 1/2" arbor for sale somewhere in the world by anyone at all that is not 18tpi.

...and consider climb milling onto the face you are creating rather than off it. That way any burrs will not affect the bottom (or top), cutting edge(s) of the file.