Having trouble turning grooves

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Frances IoM on 06/08/2018 16:11:41:
the original Perris from which the ME90 derives used BA for most sub 0.25" screws – usually 4BA but think there were a couple of 2BA – might be worth buying a couple of these as testing the thread per MG is a right pain – much easier to have a selection of known screws and see which fits

.

I'm struggling to follow the logic, Frances

The toolholder is an 'aftermarket' item, so Perris and Cowells would seem to be irrelevant.

MichaelG.

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Based on the latest hyper-accurate measurements, 4-40 UNC looks a good candidate.

 

Edited By Michael Gilligan on 06/08/2018 18:29:10

[JasonBModerator @jasonb]

But you could whip out one of the screws from the lathe and try it in the hole to see if it is 4BA.

From past iffy screws in far eastern items I doubt it is BA as they tend to use Whit or UNC with Whit being the more commonly used and closer to the thread angle Michael measured than UNC

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 06/08/2018 18:34:38:

But you could whip out one of the screws from the lathe and try it in the hole to see if it is 4BA.

From past iffy screws in far eastern items I doubt it is BA as they tend to use Whit or UNC with Whit being the more commonly used and closer to the thread angle Michael measured than UNC

.

A couple of points, Jason, before I leave you to it:

1. The thread angle on the dodgy screw is probably of no consequence … which is why I suggested checking the tapped hole.
2. I have enjoyed the exercise of trying to guess the thread, and hopefully Steve has learned a little on the journey … His next mystery thread might be in something that is not so readily modified.

MichaelG.

[Anonymous]

I hate 4-40UNC screws! They're the standard for screwlocks on RS-232 connectors. Albeit brass, but I've lost count of the number of times I thought just a final nip up, and ping the **** screw breaks. I've had the same happen with 3/16" BSW bolts, so I'd expect 1/8" BSW to be similar. All basically too coarse a pitch for the diameter.

In my experience "professional" far eastern tooling uses metric screws, although made of cheesium and therefore need replacing. Hobby grade far eastern seems to use BSW for some reason. No idea why?

Andrew

[SherlockParticipant @sherlock]

 

Posted by Michael Gilligan on 06/08/2018 18:18:31:

O.K. this is my best estimate from your latest photo, Steve:

I think that's as near to 40tpi as you will get from measuring five threads with a chopstick.

MichaelG.

 

 

Valiant effort Michael Thank you. Up until I started this thread, I had never even heard of the British Association thread standard! so I have learned a lot.

 

Posted by JasonB on 06/08/2018 18:34:38:

But you could whip out one of the screws from the lathe and try it in the hole to see if it is 4BA.

 

I shall definitely be investing in nut and bolts sets in every thread standard I can so I can keep on hand to test in future

Edited By Steve Sherlock on 06/08/2018 20:53:10

[Anonymous]

Posted by Steve Sherlock on 06/08/2018 20:52:39:

I shall definitely be investing in nut and bolts sets in every thread standard I can so I can keep on hand to test in future

You'd be better off investing in taps, even if secondhand. External screws are relatively simple to identify compared to threaded holes. And taps should be more accurately made than mass produced bolts. Plus, once you've identified the thread, you can use the tap to thread more holes!

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

Steve,

I've just found a set of three videos about the 90ME which you may find of interest: **LINK**

https://m.youtube.com/channel/UCf-ZiCQo0pfvubnP7M48_Fg/videos

MichaelG.

Edited By Michael Gilligan on 07/08/2018 08:19:51

[SherlockParticipant @sherlock]

Posted by Michael Gilligan on 07/08/2018 08:05:54:

Steve,

I've just found a set of three videos about the 90ME which you may find of interest: **LINK**

https://m.youtube.com/channel/UCf-ZiCQo0pfvubnP7M48_Fg/videos

MichaelG.

Edited By Michael Gilligan on 07/08/2018 08:19:51

I really enjoyed those Thank you Michael. Excellent viewing with a morning coffee. Being someone who spent my childhood taking everything I could get my hands on to pieces to see how it worked, I particularly loved the tear down and gave me a more intimate understanding of my machine and how it works. Invaluable. Thanks

[duncan webster 1Participant @duncanwebster1]

Posted by Andrew Johnston on 06/08/2018 19:21:30:

I hate 4-40UNC screws! They're the standard for screwlocks on RS-232 connectors. Albeit brass, but I've lost count of the number of times I thought just a final nip up, and ping the **** screw breaks. I've had the same happen with 3/16" BSW bolts, so I'd expect 1/8" BSW to be similar. All basically too coarse a pitch for the diameter.

In my experience "professional" far eastern tooling uses metric screws, although made of cheesium and therefore need replacing. Hobby grade far eastern seems to use BSW for some reason. No idea why?

Andrew

I totally agree about 3/16 BSW, for some reason it's the tap most likely to snap. Must be to do with the thread depth/core diameter relationship. However 1/8 BSW is 40 tpi, and seems benign by comparison. All academic, I use metric for preference nowadays

[Ian S CParticipant @iansc]

Just because of the gear I had when I started this hobby, the two main threads I use are 1/8"BSW, and 3/16" UNF, although in later years I have branched out a little. One surprise I got was when making parts for a 1932 Lanz Bulldog tractor, the threads were BSW. Bulldogs built in the latter half of the 30s went metric.

Ian S C

[SillyOldDufferModerator @sillyoldduffer]

Posted by Steve Sherlock on 06/08/2018 20:52:39:

…

…

I shall definitely be investing in nut and bolts sets in every thread standard I can so I can keep on hand to test in future

…

Welcome to a hobby offering so many choices. The history of threads is fairly chaotic, which is why it's possible to bump into so many variants.

Metric fasteners are used in almost all new machines and they are easier and cheaper to source. The main exception is the USA, but even there metric threads are gradually taking over. Another exception is if your interest is in older British machines, restoring old cars or whatever. In that case BSW and BSF are your friends. US and British threads were unified in 1948, so there are at least three common variants of imperial. Another golden oldie is BA threads, which were widely used on instruments and electrical equipment.

I thought about this and, because I've no particular reason to go for an older thread, I decided to go metric. It makes life simpler! I own a box of metric nuts and bolts, metric studding, and taps, dies, and a lathe to match. I also own a small imperial capability, bought for special cases. Quite a few take the opposite line, preferring to work in Imperial, with some metric for special jobs. With a bit of cash, all combinations are possible. What suits best depends on what you do.

More good news, thread gauges are affordable. Well worth buying a few if mixed threads are a problem, for example this pair from ArcEuroTrade cover Whitworth, US and Metric for about £14.

Part of the 'fun' for beginners is discovering what's available and who sells it. I'd recommend browsing the likes of ArcEuroTrade, RDGTools, Noggin Metals and other advertisers on the forum to see what's on offer. Quite often, it's easy once you know what to look for, or how to ask the question. Also the more you explore, the more it makes sense.

Dave

[SherlockParticipant @sherlock]

Thanks for that information Dave. Being a whipper snapper to some of you guys I am more familiar with metric as I use it daily, so its definitely the most comfortable option for me that allows me to work fastest.

However I tried a small pneumatic project a few months back that opened up a can of worms for me concerning different thread standards and variations. I was trying to source a particular fastener that turned out to be a nightmare and a fair bit of expense through wrong fasteners ordered as a result of my lack of knowledge in the area so I am always happy to learn more concerning threads wherever possible! Thank you.

[JasonBModerator @jasonb]

Ah yes the metric world used "G" threads or BSP to us on pipework.

And to confuse you more the thread size related to the bore not the OD

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 06/08/2018 19:21:30:

In my experience "professional" far eastern tooling uses metric screws, although made of cheesium and therefore need replacing. Hobby grade far eastern seems to use BSW for some reason. No idea why?

Probably Indian, not Chinese.

[Paul MParticipant @paulm98238]

I hope this reply is not too late. Setting up a parting tool correctly is an art. I suggest you take a look at this Youtube video as the guy who produces these is well worth listening to. I have solved many problems using this guys channel.

[SherlockParticipant @sherlock]

Posted by Paul Mills 1 on 22/08/2018 12:37:58:

I hope this reply is not too late. Setting up a parting tool correctly is an art. I suggest you take a look at this Youtube video as the guy who produces these is well worth listening to. I have solved many problems using this guys channel.

Great stuff, Thanks. I'll give that a watch. I actually watched his video on knurling before and found helpful. Didn't realise he had other vids on there

[Howard LewisParticipant @howardlewis46836]

Dribbling soluble oil, or even neat cutting oil, onto the cutting edge of the tool sometimes makes life a little better, when parting off (parting tool inverted in rear toolpost, but with no top rake)

Some times chatter can be eliminated by increasing the feed,. Under no circumstances allow the tool to rub.

Howard

[Author]

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