Member postings for Phil P

Myford ML2

Myford ML4

Unimat SL

Myford ML7

Krak (antique treadle lathe made by Parkinsons Shipley)

Pultra model P

Harrison L5A

Myford S7

Pultra 1750

Boley watch lathe

Still got the last four

Phil

Centec 2A

Centec 2B

Adcock Shipley 1ES, with Bridgeport head grafted on to horizontal overarm

Alexander Master Toolmaker

Boley & Leinen Jig Borer (predecessor to BCA)

Still got the last two.

Phil

I have heard about a Myford lathe that has recently been removed from a deceased model engineers workshop in West Yorkshire.

Not sure if it is still available for sale, but I could make some enquiries if you want.

Phil

You could do worse than have a look on MEM at Ramon,s post on lapping and honing.

http://www.modelenginemaker.com/index.php/topic,1908.0.html

LINK

Phil

Edited By JasonB on 15/07/2019 13:41:26

My wife always passes comment when I mention boring heads !!

Good result on those castings.

Phil

Edited By Phil P on 15/07/2019 12:51:07

If you go to about half way through this video, it shows a typical setup being used.

**LINK**

Some of his other video's are worth a look too.

Phil

I get why you would think that, in theory I suppose you are right. However in practice what normally happens is that the tool flexes and gets pushed inwards as the cut progresses and you end up with a tapered hole.

If you turn up a test bar with a normal tool on the outside diameter, lets say nominally 1" diameter and 4" long, then measure its actual diameter at each end, unless your lathe is very well set up you could easily find a thou or two difference in diameter across the length. Well this will also happen when you are boring a hole, as the conditions are just the same, but if you spin a cutting tool it does not matter that the saddle and spindle are not 100% in line, the tool will follow a circular path and the saddle will just be moving the job along past it. You only have to ensure the job is set up square on the cross slide.

A lot depends on the depth of hole in relation to its diameter, I read somewhere that anything over four diameters deep and you will encounter the problem of boring tool flexing.

Every job has to be taken on its own merits, there is no hard and fast rule to follow

For a relatively short depth hole, more often than not I will drill a hole somewhat under size, which could potentially have wandered off course due to the drill not being correctly sharpened or flexing off centre. I will then go down the hole with a boring tool to bring it back concentric again, and finally finish it with a reamer.

But for something like an engine cylinder bore, the between centres bar is the way to go, and even after boring it to a few tenths under size I will make an expanding hone/lap to finally finish it to size (I DO NOT mean those three legged glaze buster contraptions).

Howard mentioned he was making some tooling that is going to be used on the cross slide, in that case it would be a no brainer for me to machine it with a between centres boring bar on the cross slide where it will be used, it has to be bang on centre height and truly round if done that way.

Hope this helps, its a case of horses for courses.

Phil

I still think option 3 is going to give the best results, if you want to be quick but not fussy about the end result you can bore out a long hole on the lathe, but the tool will be springing and flexing all over the place and the method relies on your lathe being in perfect alignment and being able to turn absolutely true over a long length.

With a between centres boring bar, granted it is fiddly to set up, but you can be certain that the cutting tip will always follow a true circle and it will continue to do so for the full length of the job. Usually the boring bar can be nearly as big as the hole you are boring so long as there is room for chip clearance, hence it will be much stiffer than most lathe boring tools as it is supported at both ends. The fact that it is between centres adds to the accuracy achieved as well.

Phil

The tool stationary and the work spinning (as on the lathe) could lead to tool flex and a tapered hole. Also any out of balance or spindle bearing issues will affect the hole geometry and finish.

If you keep the job stationary and spin the tool (as on a boring head or between centres bar) then the only path the cutting point can follow is a true circle and you are more likely to get an accurate and parallel hole, this assumes the spindle bearings are good.

Just think about how often you see jobs in mainstream industry bored on a lathe faceplate compared to on a jig borer or horizontal borer, however as model engineers, we have to make do with what machines we have available.

But as a rule of thumb spin the tool not the job wherever it is practical.

Phil

These collets are actually designed to collapse over the full length, they have a double taper where they get pushed into the collet holder, and a single taper that the nut pushes against.

Probably not quite as effective gripping power as an ER but still pretty good, I have used them for years with no problems. If you make your own collet holders the two internal tapers have to be precisely located with respect to each other to ensure they share the load and collapse in a parallel manner. I have made special reamers with tapered depth stops to facilitate this.

It is the middle two at the bottom of the next photo, they are for DA200 and DA300 collets.

I also use DA180 for work holding.

Phil

Chris

The Hofmann rotary table was available in two guises, one has division plates and the other has a normal graduated hand wheel.

I have the 8" division plate version myself and agree with you that it is a superbly made bit of kit.

When you get one, let me know and I will send you a spead sheet showing all the available divisions and the number of holes in the plates etc.

There is a 10" one on ebay just now.

Phil

Edited By Phil P on 07/07/2019 22:11:34

OK lets put this to bed, I have stuck with cap head screws and just slightly domed the ends. The Tool "Holders" are now finished.

A few piccies.

Some people might not recognise this toolpost design, it was originally intended for an Emco lathe. I bought the original block and one tool holder from Neil Hemingway in Rochdale many years ago.

The quick change toolpost visible at the back of the cross slide is like a miniature Dixon type but the tool holders are less than 2" long so it is tiny. It gets used with various parting and grooving tools as well as chamfering and boring bars, all upside down of course. I have made a few special holders for this one as well.

Phil

Having now seen how much these square headed screws are going to cost me, the true Yorkshireman instinct has brought me to my senses and I am going to stick with cap heads and just modify the contact end so the thread cannot burr up.

I am now making an additional four toolholders each having three screws, but the seven I already have are currently fitted with cap heads and have been for the last 25 years or so.

33 new square head screws would be very costly, so cap heads all round is the plan, anyway thanks for all the advice guys.

Phil

Hi Barry

Thanks for the info, but they do not seem to do M5 ones, or if they do I could not see them.

I thought the prices were for a pack of 10, but it seems they are the price each !!, so I am not too worried that they don't have what I need.

I will have to keep searching, I know they are available somewhere, because they are used on the small "Multifix" cloned toolposts.

Cheers

Phil

Hi

Does anyone know where I can buy some M5 x 25mm or 20mm long square headed set screws please, these are to fit some quick change toolposts I am making.

Thanks

Phil

Just a quick update on this one.

I have just finished a total rebuild and refurbishment of the Fobco as a standard bench drill, but whilst doing it was offered a Boxford PD8 floor standing eight speed drill fitted with inverter speed control also.

So I have decided to to buy the Boxford instead and let the Fobco go to a new home. See adverts section.

Phil

That industrial stand is worth a bob or two on its own.

When my dad bought his brand new Super 7 (belongs to me now) in the late 80's, he insisted on having that type of stand but was told they no longer made them as they were too expensive to produce with the rolled edge tray etc.

They ended up finding a good secondhand one and re-finishing it just to sell my dad the new lathe.

Phil

Edited By Phil P on 13/06/2019 19:22:05

Rob

I have just sent you a private message. I have a parts diagram that might help you.

Phil

I have the whole series as a scanned PDF, but it is way too large to send as an attachment.

Phil

Hi Nick

I know it might not be in the spirit of doing everything yourself, but you can buy a 2mm chucking reamer in the UK for less than £2 post free on Ebay, even if the quality is not perfect I think at that price I would be tempted to buy one and try a test hole before making one.

Phil