Proxxon PD400

[Miner]

Wong,
Whenever possible it's better by far to support the workpiece with the tailstock and a dead or live center. Second best would be the fixed steady. If your having problems with your workpiece coming out of the chuck on any lathe then it's time to reasses your working methods. That certainly isn't normal and it would put a massive strain on the chuck jaws and scroll with possibly permanent damage done to the chuck.

While you can learn a lot from these forums, There's no sustitute for a decent book. I'm going to recomend one that you'll learn a vast amount from. It really should be read by anyone who owns machine tools no matter what their skill level is. "The Model Engineers Workshop Manual" by George H. Thomas ISBN 1-85761-000-8

This book not only gives the how to do things, But in a lot of cases gives the reasons why things should be done this way.

Pete

[Fergus OMore]

Actually, I have already recommended GHT via the Chris Heapy site which contains a lot of what Thomas made.
Again, much of my  'recommendations' are bits out of either MEWM or  his Workshop Techniques.

It's rather interesting to mention that Bill Bennett, the Editor, was instrumental in me getting my first Super7B

[Miner]

Well there you go Wong, You now have two recomendations about the same book. I've said this before on another forum, But we as hobbiests sometimes take machining as a hobby far too lightly as far as our education about what were trying to accomplish.

Consider the fact that anyone today entering the machining trades as a professional, Then at least 4 years minimum are required as an apprentice just to gain an entry level position as a fully qualified machinist. That apprentiship requires both studying book theroy, classroom time, and hands on continous practice, and then yearly testing. Yet some of the perceptions on forums like these are that you just easily learn everything by trial and error. It's rarely mentioned, But buying as many books as you can and studying them is just another part of what's required in this hobby. I've seen many projects on various forums that even some professional machinists would have trouble duplicating. There's no doubt in my mind that these hobbiests spent a lot of time and effort to educate themselves as much as possible.

Now if anyone can provide a logical argument about just why Norman and myself are wrong about this, Then I'd very much like to hear it.

Pete

[Rob.Wilson]

Consider the fact that anyone today entering the machining trades as a professional, Then at least 4 years minimum are required as an apprentice just to gain an entry level position as a fully qualified machinist. That apprentiship requires both studying book theroy, classroom time, and hands on continous practice, and then yearly testing. Yet some of the perceptions on forums like these are that you just easily learn everything by trial and error. It's rarely mentioned, But buying as many books as you can and studying them is just another part of what's required in this hobby. I've seen many projects on various forums that even some professional machinists would have trouble duplicating. There's no doubt in my mind that these hobbiests spent a lot of time and effort to educate themselves as much as possible.

Now if anyone can provide a logical argument about just why Norman and myself are wrong about this, Then I'd very much like to hear it.

Pete

Very well put Pete ,,,,,,,,,,,,,      

First place i go for information when faced with an engineering problem or looking for ideas   is my collection of  engineering books 



Rob

[wongster]

Hi Pete,

Noted your comments.  I did a search for the book and finally get it over at Hemingway Kits (hemingwaykits.com).  Lots of links are dead or books out of stock.  For GBP23 excluding shipping,  the price is right.  The first link I found has it at over GBP100.

The reason I bypass these books (bought a few of the Workshop series) in the past was because most of such books are tied in with a certain brand or kind of machine.  I only had the Sherline and therefore found that some stuff weren't appaent to me.  As someone new, I get confused.

I didn't use a tailstock for this job because the last time I tried on a test piece of brass, I've an error of 0.06mm in about 100mm of turned length (headstock side is larger).  Will be playing with the tailstock after I completed this part.  Want to do some work first to keep the momentum going.

I believe the stock flying out of the sherline chuck was due to my ignorance of what was needed.  I am rather gentle when feeding in the tool now and start cranking faster when the feel is right.  As those Sherline owners kept telling me, work within the envelope of these machines.

I've been reading online and using the forums to learn about machinging from scratch.  Some views are conflicting to the others I received.  To me, these are common as different people have varying background and experiences.  Arguments are good if done cool headedly; very constructive as it gives quite a lot of insights to the topic at hand. Heated argument turns things ugly.  The most common topic I often read that insults were exchanged at later part is "Windows Vs Linux".  I always like to think "do what you think work best for you".

I would like to thank each one of you here that chim in to help a newbie with a new machine out.  Keep up the good spirit!!!

 

Regards,
Wong

[Pete.]

Get the book - I have 'how to run a lathe' and 'Screwcutting in the lathe'  - but also get stuck in! Getting comfortable and familiar with your lathe is just as important, and will help the theory to 'make sense' in a way you can really relate to if you've had the problems and struggled with them.

[wongster]

Sure Pete.  Lots of reading from now.  My elder girl has just started her secondary school education (age 13, in case the term used is different).  I'm like going back to school with her... 

Regards,
Wong

[wongster]

Hi guys,

I was considering getting the ER32 collet chuck with MT3 shank from CTC Tools but couldn't figure out how to use a drawbar on this lathe.  the bore at the end of the spindle is 20.5mm and If I make a draw bar with a big head, I've to leave the gear box compartment open as the box will be in the way of the drawbar bolt head.

This got me to wonder; what can the MT3 bore be use for then?

Regards,
Wong

[Miner]

Wongster,
Depending on your own thoughts and future needs? You might be better off building a spindle adapter that uses the ER-32 collets and the collet nut. This allows longer work to pass thru the collet and use the hollow spindle on your lathe. Without that your somewhat limited to short work pieces or using a tailstock live/dead center or the fixed steady. My own opinion is that it's a much better setup. There's numerous examples showing how people designed and built them on this and many other forums.

With anything inserted into your lathes MT 3 spindle taper it's an absolute requirement that both the male and female tapers are spotless. MT's work by a wedgeing action. A .001 piece of swarf or dirt will reduce that holding power and possibly damage your internal spindle taper.

Dead centers can be used in your headstock while turning between centers. Which by the way is the most accurate way of turning work if it has to be removed and rotated end for end for further work. Even more accurate? Turn up a piece of scrap material while it's held in the 3 jaw with a 60 degree included angle that matches your center drills. With work bolted to your cross slide, Then drill chucks, Boreing heads etc can be also used in the heastock taper.

I know exactly just how tough it is to not get impatient and start building parts, But with my own hindsite experience? I'd highly recommend reading at least once that GHT book before ordering any accesories or even going much further with your new lathe. You'll be far more educated and have a much better ability to judge exactly what you want to do. In the long run that will save you money or possibly even permanent damage to your equipment.

Pete

[wongster]

Hi Pete,

The book should arrive sometime this week, I hope.  I wrote to Hemingway Kits towards the end of last week to check the status of my order as I only received a note saying that my order has been received.  I was told that it was sent out on the 10th and to allow 7 to 10 days for delivery.

I wanted to try to turn between centers last weekend but didn't have a face plate and a lathe dog for this lathe (I've them for my Sherline).  I was checking out the Proxxon's pics on their "Centre Turning Accessories". They're sold as a set with a faceplate with 30mm bore, a drive pin that screw onto the headstock flange and faceplate, with 2 reducing bushings (30/20mm and 30 to 15mm), and 2 centers (MT2 and MT3).  This looks like a project I can add to my list.

On the use of the MT3 taper, you mentioned this:
"Turn up a piece of scrap material while it's held in the 3 jaw with a 60 degree included angle that matches your center drills. With work bolted to your cross slide, Then drill chucks, Boreing heads etc can be also used in the heastock taper.", which I don't quite understand.  Can you elaborate?  Also, can I hold drill chucks and Boring head in the headstock taper without using a drawbar of sort to hold them to the headstock?

When I use a drill chuck in my Sherline headstock (with MT1 taper), a drawbar holds the drill chuck.  With the PD400, I don't know how a drawbar can be used with the 20.5mm spindle bore.  I've the 2 pics here to illustrate what I mean.

The spindle bore can be seen through this hole on the gearbox cover:


With the gearbox opened:



Regards,
Wong

[Fergus OMore]

Have you a faceplate? If you, that is a rather big catchplate. If you haven't, use the three jaw with a centre in it.

Hope you enjoy your GHT.book

[wongster]

No, Norman.  I don't have one yet.  I can order one.  The Centre Turning Accessories sold by proxxon are not that expensive.  Just the waiting time for the fulfillment of the order.

Maybe I'll go get a MT3 centre later.

Regards,
Wong

[andyf]

Hi Wong,

The drawbar: If the hole in the gear cover B is ~3mm larger than the outside diameter of the spindle, you can make a nut with a boss projecting from it. The boss will have two diameters, one being about 24.5mm to pass through the hole and push on the end of the spindle, and the second about 21mm to fit inside the spindle bore to locate the nut.

If the hole in the gear cover is too small for that, either enlarge it to around 25mm or make a nut as above, but with the hex section of the nut smaller than the hole. This will allow you to tighten the drawbar and then close the gear cover.

Or do what many of us would do - run the lathe with the cover open, and keep your hands clear of the gears and pulleys. I think you had a Sherline, and they don't have a cover over the pulleys. If you still have all your fingers after using that lathe, you will probably not lose any of them with the Proxxon.

Andy

[Miner]

Wongster,

With a MT 3 arbour and drill chuck in the spindle, Work fixtured to the cross slide and at the correct elevation, Your only drilling into the work. That end thrust helps to keep the MT taper tight. Using a MT-3 type milling chuck to do milling that would put side loads on your taper and chuck would require a drawbar. After looking at your pictures, You could machine something that fits the outer end and inner bore on the left hand end of your spindle like a stepped washer. Buy a long enough bolt that matches the drawbar threads in your MT arbour and then machine the bolt head to thin it enough so that your lathe door will open. You also DO NOT WANT TO TIGHTEN THAT DRAWBAR UP REALLY TIGHT. There's no need. That drawbar is only to prevent the MT from moving out and becoming loose. The tighter you have the drawbar then the tighter your wedgeing that male MT in place. That would then require very hard hammering on the end of the slightly loosened drawbar to push the MT out enough so it's released from the bore. All that hammering is REALLY bad for the lathes spindle bearings.

As far as the scrap metal and machine it to at that 60 degree angle? That's the most accurate way so you'll have a point machined true to the lathes center of rotation. It's been machined while rotating within the spindles own bearings. But!!!!! It has to be machined and left in place. As soon as you remove it from the chuck you'll have to slightly remachine it true each time you want to use it again.

Work can be held on the lathes cross slide and be machined in the exact same way as it would in a normal vertical milling machine. All you have is a small, short travel, vertical mill lying on it's back. Work size, table travel, and rigidity is obviously far less than a compareable weight vertical milling machine. A proper lathe milling attachment that fit's your lathe would give you an easy way to set the work to the correct elevation. But it's not a great substitute for a proper milling machine.

I mentioned the use of drill chucks, milling chucks, boreing heads, etc with a MT-3 arbour as a few examples because you had asked what that headstock bore could be used for.

Believe me, After reading thru GHT's book even once, Then all of this will make far more sense and be much more understandable to you.

I've edited this to add,
That GHT book isn't the only information you'll ever need. I'm certainly not trying to complicate the issues or sidetrack them off elsewhere. But machining as a single subject even at the hobbiest level is so vast that you'll never learn it all. That's what keeps it interesting. If you stick with it you'll never quit learning.

Pete

[Fergus OMore]

Might I add a little bit to Pete's excellent comments?
Initially, when one bought a lathe it came with a pair of centres and a faeceplate as STANDARD. None of this rubbish about 'get a three jaw chuck' and then the rest will follow. Frankly, nothing can be further from the truth. The next bit of the armoury is a FOUR JAW INDEPENDENT CHUCK.
With either a faceplate or a 4 jaw, you can hold a drill which you can with three jaw but you can hold round or square stuff, make a boring bar, hold odd shapes for facing and a multitude of tasks like making nuts and bolts, tool holders and so on.

Before moving to 3 jaw stuff, probably the next thing is a drill chuck or two and a heap of Morse taper blanks. True, you are making your lathe into a drilling machine and as Pete says, a milling machine. In all honesty, the use of a lathe to work between centres is the last thing on most minds. Think carefully, but if you are going to work 'between centres' you are going to need a fixed steady and probably a running one and - some means of slowing your lathe down to screwcut- without having a heart attack!  You can make the steadies with either a faceplate or a four jaw but you are going to be very skillful to do it all on a three jaw.
 Maybe I'll get banned or burned as heretic or something really exciting.  Or get a lecture on the merits of carbide tooling or even parting off. These will really be a treat.

We'll see. Meantime, enjoy GHT.

[wongster]

Lots of info. Letting them settling into my head.  May need some files to thin the outer shell for more to pass through...

Andy, the gap between the spindle end and the cover is rather small.  I think I can file the plastic thing (any name for this protruding circular thing with a hole in it?) shorter to make more space for a thicker bolt head.



I believe the bolt head can bear against the end of the spindle though it only measures about 1.5mm in thickness?



The hole in the cover is almost 25mm but the alignment is off to one side (spindle bore and the hole in the cover are not concentric). By the way, is the "nut" you mentioned the head of the bolt of the drawbar or it is really a nut to be fastened onto a rod making the drawbar?

Pete, the Sherline lathe has MT1 spindle which I mounted tools, collet chuck (ER16) etc.  Except when using the faceplate with dead center in the spindle, I use the supplied drawbar.  I asked about how can I do with the MT3 spindle bore on the proxxon lathe because I couldn't figure out how to use a drawbar on it.  Thanks for clearing the part on its possible use without the drawbar.

I've 2 Sherline mills (one CNC'd and one for manual work).  May not do vertical milling on the lathe that often unless when need arises.

Norman, I just ordered this afternoon (SG time of course  ) a 4-jaw independent chuck and the centre turning accessories.  When I bought my lathe, I also purchased the fixed and follower rest (or traveling steady per proxxon website).  I did cut external threads on a piece of steel to make a bolt with a short length of stainless (stainless because that was the only piece in my box with close enough diameter) sticked into the bolt head to make a locking lever for the tailstock.  Now I don't have to search for the hex key to lock or unlock the tailstock.

I'll continue to look for simple projects to do to get the basic right before moving to more complex stuff.  The collet chuck for ER32 collets (those that mount onto the backplate of the lathe) will be one I would like to attempt.  Most importantly, I want to learn clockmaking.

Regards,
Wong

[Fergus OMore]

Good news about getting steadies and a 4 jaw chuck.

When you get your copy of GHT you will find lots of small tools described which make your future machining so much simple. Some of the  dimensions of drawings will apply to a Myford with a 7" swing but if you photocopy , you can re-dimension them to suit your lathe. Sort of use typewriter opaque fluid and write in the new figures. I do a lot of photocopying pages and put the sheets in transparent covers. You will, of course, do your own thing and discover methods  for yourself.

Miner( Pete) mentioned work bolted to the saddle- and I agree. The old hands, including GHT, had a chunk of steel or cast iron that bolted on the saddle and they peppered it with holes, sometimes tapped, sometimes bolted to hold work securely and to mill or drill or tap from the headstock. When the bit of metal was too rough with holes, they simply got a new bit of metal- and made more holes.

Again, I would make a rear parting tool which GHT describes. Contrary to 'other opinions' GHT developed and developed an old design which I have traced to a gent called Ian Bradley who wrote extensively and wrote amongst other books, one on the Myford 7. Perhaps you should have a look at the Chris Heapy site which shows some of the Thomas work.  OK, you will find that Heapy's site is no longer in use but a Japanese worker has sort of brought it back for reference. Actually, I'm making a variant of Thomas's 'mandrel handle' because I made up one, moved my home and workshop and changed my lathe and- well, felt a change to having a neat one was important.

You have my E-mail address and I look forward to comments or questions.

[Miner]

Wong,
I can't help you with any information about clock making since I know less than nothing about it. I believe a gentleman by the name of John Wilding? wrote a lot of books about the subject for the hobbiest. Someone else here that's far more knowledgeable could correct my information if it's wrong.

Pete

[andyf]

Wongster wrote:
I believe the bolt head can bear against the end of the spindle though it only measures about 1.5mm in thickness?

Yes, that would be perfectly OK. The surface area at the end of the spindle will be around 100 square millimetres, which is plenty.  You won't damage the spindle when you tighten up the drawbar unless you have superhuman strength, and as Pete (Miner) says, it doesn't need to be tightened very much to stop a Morse taper slipping, and overtightening will make it difficult to get the tapered item out of the spindle.

By the way, is the "nut" you mentioned the head of the bolt of the drawbar or it is really a nut to be fastened onto a rod making the drawbar?

Normally, a drawbar is in the form of a long bolt, so I should have referred to the head of the bolt. Sorry I called it a nut; that is because I was forced to use separate nuts on two drawbars (M10 and 3/8" respectively) which I made for my milling machine.

Andy

[wongster]

Norman, thanks.  I will.  I'm rather up to date with my blog, when I had time in the shop.  Each post is usually written about a session I had, mistakes and all - I don't like to hide my ignorance; If I screwed up, I'm honest about it.

Pete, I heard of that name.  I bought 4 books and 2 DVDs from WR Smith on clockmaking.  Will have to postpone this till later.  Some topics covered are a little tough for me at this moment.  I usually buy when I see things I like, and keep them till I'm ready to work on them in case I forgotten where to get them or they went out of production.  This is what I did late last year.  I cleared up the last 5 Casio Financial Calculator FC200 (the old model) that is no longer in production.  The shop had 5 pieces left and I took them all even though I've 2 in use.  I always have 2 in my working bag and would like to have 1 in the office and some spares at home.  The aluminium backing tends to go out of shape causing bad contacts in the buttons.  I make a living using this model for the last 17 years so might as well keep some spares around.  Cost me quite a bit as there are no longer any market price...

Andy, no apologies needed.  I just want to also learn the lingo for more effective communication.  I wonder why Proxxon put a plastic hole in a manner that would hinder the use of a drawbar.  Measuring the required length would be a challenge.  I'll order a ER32 collet chuck with MT3 shank from CTC Tools and use it as reference to cut the internal taper to make the collet chuck that mount on the backplate.  Been reading online in this forum and other sites on how that was done by others.  Do you have pics showing how they're put together?  It may be easier to use a threaded rod and use nuts at the other end.  Don't have to worry about measuring and finding bolt of specific length.

Regards,
Wong

[andyf]

Hi Wong,

It would be easier to use threaded rod. I assume that you will need an M10 thread. The head will be so large that making the drawbar out of bar stock would waste a lot of material. To avoid having a separate nut, you could make a big M10 nut, and experiment to find where it needs to be to get the drawbar to the correct length before cutting off the excess rod and welding or brazing the nut permanently in place.

Making a bolt-on collet chuck shouldn't be too difficult. I don't think you need to buy one with a Morse taper shank to copy. The taper is 8 degrees (16 degrees included angle) as shown on the drawings here http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collets-Collet-Chucks . Test the taper with a collet into which you have inserted a bar of the maximum size it is supposed to hold (for example, a 6mm bar in a 6 to 5.5mm collet) so the collet can't compress as you push it in. Make the chuck a bit too long, and then trim back the outer end so that about 2mm of the 8 degree taper is projecting. That will allow each ER11 collet to operate over its 0.5mm gripping range, though I see that Arc Euro's largest ER11 collet has a 1mm range (7mm down to 6mm), and that would need to have about 4mm projecting. If you can find a 6.5 down to 6mm collet, that would be better.   

Andy

[wongster]

Hi Andy,

I've not tried brazing before.  I've this proxxon torch that can generate heat up to 1200C.  Can this be used?  I tried looking for those bigger cylinder type shown on some pics here and on youtube after reading about brazing and silver soldering here.  Those places I frequent for machining stuff don't carry them.

On setting the angle on using the compound, I'm not sure how accurate is the scale on the lathe.  I tried turning to a 60 degree point (setting the compound at 30 degree).  When I measure the resulting work using a made in china angle gauge, I was off to almost 1 degree.  Is this acceptable for the taper?  I'll see if I can find a more accurate angle gauge and do some more test cut to get a feel.

Regards,
Wong

Edit: I found a simple article on  a robot making site. Saw from the pics that they used similar kind of torch I have.  I'll source for the other things needed when I've time to go shopping.  Likely after the Lunar New Year, which is just next Monday.

[andyf]

Hi Wong,

1200°C is hot enough for silver soldering/brazing, but the nut will be fairly large, and a small torch might not be enough to get all of it, and the threaded rod inside, up to red heat at the same time.  It would be easier to take the job to a welding shop.

You want the top slide to be as near as you can get it to 8° before cutting the taper, leaving only very fine adjustments to be made (if necessary) after testing with a collet and marking compound.

Use trigonometry and imagine a triangle, angles of 90°, 82° and 8° as its angles. If the side opposite the 82° angle is 100mm long, then the side opposite the 8° angle will be 14.05mm. Bring a plunger dial indicator to bear on the side of your top slide, and adjust the angle of the slide until the indicator shows a movement of 14.05mm when the whole carriage is moved along by 100mm as measured by the leadscrew handwheel and its dial. Be careful to take up any slack between the half nuts and leadscrew as you measure the 100mm. The 100 and 14.05mm can be scaled up or down to suit the length of your top slide. Scale them up if you can, because that will give greater accuracy. 

Of course, this assumes first that the indicator plunger is at 90° to the lathe bed, and secondly that the side of the top slide is parallel to the dovetails within it. The latter seems to be true on my Chinese lathe and it will probably be true on your German machine.

Andy.

[wongster]

Hi Andy,

Thanks.  I'll experiment a little.  Will post pics when I get there.

In my last session in the shop a few days back, I managed to remove the little key on the feed screw of the cross slide.  It wasn't as tightly pushed into its slot as I thought and thank God it didn't fly...    I give the feed screw a thorough clean up with a soft brush (old tooth brush) and apply way oil on it generously.  At the same time, I adjusted the gib screws while sliding the slide in and out without the feed screw installed.  It now slide nicely though I still have movement when I push the slide along the feed screw.  Backlash?  I don't have that on the compound and I ensure that the hand wheel nut are tight enough.  So far it hasn't caused any problem when I did facing cut or parting off.

Regards,
Wong