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Member postings for Ian P

Here is a list of all the postings Ian P has made in our forums. Click on a thread name to jump to the thread.

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Thread: Milling a semicircular groove, ball ended cutter, or?
21/01/2012 12:58:07
Michael
 
I have already done a CAD drawing of the 10 & 11 hole relation ship to ensure that there was always a position where a pin could be inserted.
 
Whilst there will be a significant portion of both thread profiles cut away it is not over the whole length of the thread engagement. Both the nut and the bolt will have full threads for two thirds of their length and these will be fully engaged at the point where the nut goes tight.
 
In practice the internal and external grooves could be on a smaller diameter but plain parallel spigot. I chose not to design it like that as it entails the internal screwcutting being done up to a shoulder.
 
Ian P
 
 
 
Thread: MEW 186 - Electronic Lathe Control
21/01/2012 12:44:47
Tony
 
I think I was rather hasty in focussing in on what I thought were weak points without thinking it through, I accept also that with precautions taken to overcome the shortcoming (back gear, low speed etc) threads suitable for almost everything other than feedscrews could be created.
 
Do either of the systems you describe have an option to use a shaft encoder with many more pulses per rev? Presumably that would improve the accuracy.
 
Ian P
21/01/2012 09:14:11
I'm with Billy on this one!
 
I had been aware of the term 'ELS' for many years but never investigated the forum. I just assumed it was a leadscrew only version of CNC conversion and it never got my attention.
 
I cannot imagine anyone would spend so much and go to so much trouble to cut a thread by such a flawed method. Even if the pitch was accurate enough for the job in hand, techniques like cutting a thread close to a shoulder would be fraught with difficulties.
 
I am slightly surprised that the author, a knowledgeable and skilled person could consider that this was a viable alternative to a full CNC system.
 
Ian P
Thread: Myford Rodney
20/01/2012 22:02:00
Posted by John Stevenson on 20/01/2012 21:33:51:
If I wanted a milling attachment for something like a Myford I'd buy one of the SX2 mills from ARC with the fixed column and brushless motor and sell the base on Ebay or turn it into a T&C grinder.
 
The column has a big flat base to make it easy to mod to fit.
 
John S.
 
 
If you buy an SX2 mill why on earth would you want to limit its usage by splitting it in two and bolting to a lathe.
 
Sounds daft to me!
 
Ian P
Thread: Milling a semicircular groove, ball ended cutter, or?
20/01/2012 16:04:22
Posted by tractionengine42 on 20/01/2012 15:40:27:
Hi Ian
If the nut is Aluminium and the bolt a much stronger En24 how much load/stress is the bolt going to see that would cause consern for the bolt?
 
I would consider using a carbide round nose endmill, the carbide will give a good cutter life. The end of the groove will have a radius therefore no sharp corners. I would not think this approach will give concern regarding stress concentration. The thread root will be much more of a stress raiser.
 
Hope this helps
 
Nigel
 
 
Nigel
 
I wanted the grooves to have radiused ends more for appearance than neccessity. I am a believer in 'if it looks right, it is right' and if these were made by a motor manufacturer I'm sure they would be well radiused.
 
These parts are going to hold the wheels on a car and the thread is much larger than is actually required. The M45x3 (or possibly 2mm pitch) will have a very long thread engagement and will only really be subject to axial tension loads. To reduce weight the male threaded part will be bored out to form a very thick walled tube.
 
Ian P
 
 
 
20/01/2012 15:09:31
Bazyle
 
To do that I would have to spend almost twice as much on material and then do a lot of machining (internal and external screwcutting) and then half of the parts would just be scrap.
 
I am being considerate to the environment, and my wallet!
 
 
Ian P
 
20/01/2012 12:36:33
Posted by Les Jones 1 on 20/01/2012 12:21:01:
Hi Ian,
Could you not just drill the hole using a slot drill which should not have the same tendency to wander. An alternative would be to use the same method but machine each item separately. You could even start with the slot drill taking a small amount off and move the item a little at a time between each down feed until the half hole was complete. This second method would avoid the possibility of the steel swarf cutting into the aluminium.
 
Les
 
 
Les
 
I am sure that would normally work but the job is a bit more complicated than I described when I simplified it.
 
Th male thread will actually have 10 equispaced grooves and the nut will have 11. That way wherever the nut stops when it is tight there will always be one pair of grooves that a pin will fit into.
 
There are four pairs of parts so thats actually 88 grooves altogether. For appearance (and to minimise stress raisers) I would like the grooves to run out smoothly rather than with a step that a slot cutter would leave.
 
Ian P
Thread: MEW 186, Best ever issue
20/01/2012 11:14:51
I see no point whatsoever in having listings of G code printed in the magazine, regardless of how big the circulation is I cannot imagine even one person laboriously typeing in the code by copying from the page. When I first took up 'computing' I copied code from listings for a BBC computer, because it the only way I could do it as the magazines did not include a cassette or disk in those days. The chances of getting it right firts time were very slim so much debugging was called for (very educational though!)
 
By all means show examples of code if its going to get a point over, ot its part of a tutorial, but not a listing for something that only the author made for himself.
 
I vote for putting and keeping CNC topics in MEW as long as there is some variety. I find it interesting to see how people add scales and stepper motors in their conversions although some article have left me feeling a bit cheated. As an example, some time ago there was article about integrating a rotary encoder into the base of a Myford? top slide. Unfortunately as far as I remember there was no sectioned view to show how the thing was arranged and not enough detail for (me at least) to copy even the principle of operation.
 
Ian P
 
Ian P
Thread: Milling a semicircular groove, ball ended cutter, or?
20/01/2012 10:55:18
I want to mill corresponding longitudinal grooves on the joint line between two mating parts so that when assembled a loose fitting dowel can act as a locking device.
 
The parts in question are a 'bolt' 45mm diameter 3mm pitch made from EN24T, and a nut made from aluminium.
 
It the two parts were the same material then they could be assembled first and a hole drilled, obviously that wont work in this case and as the pin needs to be a loose fit anyway so doing the grooves separately will be OK.
 
I can use an end mill to machine the groove in the nut, probably 1/4" diameter to take a 6mm pin. I think I could use a ball ended endmill to cut the lengthways grooves in the EN24T threaded part but having never used a ball end cutter I don't know how it will fare. I imagine it will be slow going and might need a few cutters to cut the grooves as I have to cut 40 in total, each about 25mm long.
 
In the J&L catalogue that show ''radius shank cutter' that looks like conventional HSS woodruff or tee slot cutters but with a radiused profile. Being in their 'Value' range they are not recommended for production work, which I take to mean they may OK for one or two grooves but not stay sharp long enough for my task. I would prefer to use this type of cutter from a finished appearance point of view as the run out at the closed end of the groove will be longer (than half the diameter of the endmill).
 
So, am I hoping for too much from the J&L cutter or will ball ended cutters do the job easily, and cheaper too.
 
Ian P
 
 
 
Thread: MEW 186, Best ever issue
19/01/2012 22:16:36
Posted by Stub Mandrel on 19/01/2012 21:08:04:
 
What Neil said here is worth reading so please scroll up a couple of posts to see it. No point me 'quoting' it all here again.
 
 
 
Neil
 
I absolutely agree with every word of your comments. You've hit the nail on the head in every paragraph.
 
Ian P
18/01/2012 21:32:14
Posted by matt on 18/01/2012 21:17:49:


Not sure about MEW 186 being best ever TBH.
Snip
Matt
 
 
When I made the initial post I had only flicked through the magazine, my comment/compliments were mainly in regard to the variety and breadth of he articles which I stand by.
I agree that like many other issues (and many other magazines) there are lots of errors and discrepancies to be found. I would consider myself to be very pedantic and some of the errors really annoy me but I dont think it is my place to criticise because I am not qualified to do so. If I ever get to writing articles I am sure I will make mistakes!
 
Ian
Thread: Making a Tool Holder for CCMT 06 tips?
18/01/2012 20:03:01
Posted by David Littlewood on 18/01/2012 17:45:32:
Ian,
 
I am doubtful about your assertion that contact between file or sawblade and hardened steel would not blunt the former - it certainly goes against my experience.
 
David
 
Yes, I accept what you say, I was referring to careful use of a saw/file. By coincidence on another post today 'corner rounding' buttons were mentioned. They are usually hardened and designed to be contacted by the file teeth. As long as no pressure is applied no damage is done to the teeth.
 
Ian
18/01/2012 13:31:47
Posted by John Stevenson on 18/01/2012 12:42:27:
Ian,
If I need to do any rough work I have another vice or the original hardened serrated jaws.
 
I hate hard jaws and hardened packings, most of mine are just pieces of gauge plate cut and ground to size. if you make a mistake all you have is a dinged packing and not a blunt or broken tool.
 
John S.
 
PS the lathe tools are a commercial job, from this photo they go for professional hardening and blackodizing.
 
I know the tools are a commercial job, I bought one!
 
If I had a choice I would have the vice jaws are glass hard. That way, and used carefully, even if the file or hacksaw blade did make the occasional contact they would just skid and not even damage the teeth.
 
Ian
18/01/2012 11:40:15
Slightly off topic but in the John Stevenson's photograph I notice he has removed the knurling of the mating faces of the vice jaws. I'm envious!
 
I suppose the knurled surface is OK for rough work but the rest of the time one ends up with putting packing of some sort to prevent damage to the work. I frequently grip anodised aluminium sheet and very clean finely surface ground jaw faces do not generally need even a paper protective sheet, Most standard soft jaws get embedded with grit and swarf and in any event do not clamp tightly right at the edge.
 
When I left school and started as a sort of apprentice an engineer at the company who made prototypes got delivery of a new vice for his bench, the first thing he did was fully dismantle it and fettle it up so that it worked smoothly. I saw him grind the jaws and the memory of his attention to details has stuck with me.
 
Not having a surface grinder I have generally done mine on a belt linisher. It would be good if someone would offer an exchange postal service! Any takers?
 
Ian
Thread: MEW 186, Best ever issue
18/01/2012 11:22:21
Its just dropped through the postbox and I have had a quick scan, I'm very impressed, a really full magazine with articles to suit everyone.
 
My compliments to the editor (and the various authors/contributors)
 
Ian
Thread: What is EN24 like to machine?
14/01/2012 09:52:56
Thanks to all that have replied. From what I have learnt I now have no trepidation in making the parts I want. Regardless of what conditions it may be available in, most of the ME suppliers sell EN24 as EN24T so that is what I will get.
 
I presume/hope that I will not need to subsequently heat treat it for this application which is, the threaded part of a classic car 'Knock on' (or centrelock) hub.
 
Ian
 
13/01/2012 22:26:33
I am contemplating turning and screwcutting a male thread 50mm diameter(pitch 3mm) on EN24 steel.
 
In the past I have screwcut small stuff mostly in non ferrous with no problems, for this project I would get a carbide tip with the correct thread form but I am wondering what sort of finish I can expect and whether something like this is well within the capabilities of a 5" Boxford
 
I have not knowingly used EN24 before but have modified numerous HT bolts, are they a comparable grade?
 
Ian
Thread: iPad in the workshop, something to bear in mind!
29/12/2011 13:41:23
Posted by John Stevenson on 29/12/2011 13:17:12:
I hate ITunes and flatly refuse to use it, too intrusive and bloatware.
 
Do a search for Copy Trans Manager, that part is free and you can move files and edit at ease.
 
Works like ITunes should.
 
John S.
 
 
John
 
I totally agree with your opinion of iTunes and have just looked at the details of programme you recommended but find its website confusing. There seem to be several versions and whilst its 'free to download' I am not sure exactly what is needed to replace iTunes.
 
It appears to perform the essential backup functions so that is fine, I do not have music files but want to be able to load and organise photos and small phone video files made on an Android phone, will it do that?
 
Ian Phillips
29/12/2011 12:26:06
Posted by jomac on 29/12/2011 12:08:17:

Terry, I flew down to Melbourne for Xmas, my grandson/daughter have I/pod and I/pad, the boy is doing vet science but of the ten boys and girls that were there, 6 were doing engineering degrees, so all up there were at least 20 down loads of the level app, They all thank you for a free Xmas present,!!!!!!!!!!!!!!!! Unfortunately, I only have windows XP, although it seems to work,and is supposed to be 64 bit, ???? My daughter loaned me her I/pad, next thing is how to link the I/pad to my computer, and down load good stuff, (I have a different ISP, and dont know her ISP).

Thanks, and have a happy and fruitful new year.

John Holloway

John
 
I am no iPad expert but my advice would be DO NOT connect it to a computer unless it is the same computer that it has been previously connected to..
 
To communicate with an iPad the computer needs to have iTunes installed. If you connect an iPad that has previously been syncronised with a different computer you will get lots of warning messages about the iPad data being overwritten and it may not actually let you do anything useful anyway.
 
In any event I think you will be disappointed with what you can and cannot download onto an iPad, its much more limited than a laptop.
 
Ian Phillips
Thread: Is 0.1 deg good enough..
20/12/2011 11:00:11
I thought the magazine article was a little light in terms of quality content.
 
In the introduction the author implies that the digital gauge will serve the purpose of a precision level, it obviously will not.
 
He describes how to turn a test piece to check that the lathe is 'turning accurately' but other than saying it must have the gibs etc adjusted correctly first does not mention that there could at least one other reason why the two bands are not of the same diameter (spindle axis not parallel to the bed?
 
This whole lathe levelling subject seems to regarded as a sort of holy grail of turning. As I see it, its not so much as levelling the bed but ensuring that it is not twisted. Historically having machines (including lathes) accurately level meant that work and jigs of any shape could be set up by just using a level and squares. Presumably laser devices and other techniques have taken over these days?
 
One thing I remember reading (in MEW?) that the 'levelling' worriers should think about is, How do you level a lathe on a ship?
 
Ian Phillips
 
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