Using a pillar drill for milling?
|Chris Vickers||23/06/2019 18:53:18|
|37 forum posts|
Hi NigelG2, wow thank you, just shows me how little i do know (-: This is most helpful.
Appreciate the insight into the milling cutters. So to clarify the threaded end ones are the bees knees as the cutter cannot come out and they have the end pin for extra rigidity.. But plain shank cutters of the correct diameter are fine to use in the collett system you describe ER20 with a draw bar, that I will in time need to make. With this holding technique just like a wood router under heavy load the cutter can slip outwards into the work, but the key will be to take it easy. My mid 1930's Myford ML1 is not exactly built for rigidity so I would not expect it to handle anything too heavy anyway.
Thank you I had not thought about the length of tee nut helping with stability, I will consider that when looking at purchasing one.
When you say the stud should not pass through the nut, I understand that to mean into the nut, but not protruding out the other side so it grounds in the bottom of the tee slot ? Just check I fully understand...
You happen to mention hardened chuck jaws, Ive noticed with some chucks for sale they come with hard and soft jaws....er..lost on me?
|Nigel Graham 2||23/06/2019 21:36:29|
|356 forum posts|
The wretched log-in system on this site...]
You can use the threaded-end cutters in plain collets as long as it's the shank that's gripped and not the thread.
Lathes are not really milling-machines laying on their backs, and a vertical-slide on the cross-slide is not ever so rigid, so you can only take light cuts at gentle feeds.
The length of the T-nut is more to spread the load than add stability, though it will do that. My smallest lathe is a 2.5" centre-height EW Stringer, and I made not T-nuts as such but T-strips to hold the home-made vice on its vertical slide. These are bars of T-section the length of the slot, with two tapped holes in each.
Yes - that's right- the stud shouldn't ground on the floor of the slot.
Lathe chucks normally have hardened, or at least toughened, jaws; but the "soft jaws" are unhardened so you can modify for special purposes, for example by cutting shallow rebates in their top surfaces to grip thin discs.
It will be worth as I have done, building up a library of reference books written for model-engineers, on workshop techniques. The "Workshop Practice" series is a good start - I've about 10 of them, each dedicated to a particular machine-tool or metalworking method, selected to suit my own needs. Have a look on TEE Publishing's web-site. As well as mail order they usually have comprehensive stands at the major model-engineering exhibitions.
Note that some reference books appear to be mainly handbooks on making tools and machine-tool accessories, leading to a somewhat unfair reputation of making tools to make tools - but they are still full of valuable information. Harold Hall's books are project-led but in a progressive way, so if you follow them you create genuinely useful tooling as well as gaining experience; without being submerged in cutting-tool theory deeper than strictly necessary to start obtaining decent-quality results .
The older books, by such writers as Stan Bray and L Sparey, are a bit more general and if you own old machine- tool like your Myford, a handbook closer to its era will be more attuned to its capacities and likely to cover the subject of milling in the lathe.
|Chris Vickers||24/06/2019 18:48:19|
|37 forum posts|
Hi Nigel many thanks again. Of course I had to look up to see what an EW Stringer lathe ls like...looks fab!
I'm quite sure if I had the room and funds I could collect old British lathes.
That's good to know about soft jaws, is this a recent thing ie offering both hard & soft jaws? I would presume the jaws on my vintage lathe would be considered hard.
Regarding books yes I got The Amateurs Lathe by L Sparey, read most of it but skipped the milling section as back when I read it a few months ago I was not considering milling..so now I will read it, and in time add to my engineering library.
Yes building tools,... no doubt like sharpening them in the wood trades, one can get bogged down in this (the latter). That said the sensitive pillar drill project looks like a very useful bit of kit, cannot decide right now if I want to spend the time building one or buy one ready made if it turned up. I know how useful they are for tapping as i have a horrible Ali, chromed metal and plastic affair which whilst looking orrible/ offending my eyes is a real help keeping things straight....but its not great!
I found some parts I needed for my Myford ML1 on eBay but I'm still looking for a Bull wheel gear Guard which has the single point fixing rather than two bolt holes on the later models.
|Nigel Graham 2||24/06/2019 20:10:11|
|356 forum posts|
That EW lathe needs refurbishing, but it is probably as old as me and yes, I do have a Bus Pass. My parents bought it for my 18th birthday present, from one of Dad's work colleagues. By Tony Griffith's Lathes web -site, it has all the optional extras except one - the change-wheel guard.
I think the oddest task it's done was screw-cutting a spare, special adaptor for connecting a keg CO2 cartridge to a heat-exchanger forming the core of a warm-air breathing kit owned by a cave rescue organisation. It's used to ward off hypothermia. The thread to be cut was metric but also completely non-standard (a common commercial dodge); the lathe is all-Imperial with an 8tpi lead-screw and change-wheels in 5-tooth steps from 25 to 65 teeth, so calculating the combination for the closest match was entertaining to say the least!
The concept of soft jaws is nothing new at all but finding ones for a particular, old make of chuck is another matter. Normally chuck jaws are hard, otherwise they would wear rapidly.
A neat aid for using a drilling-machine as a tapping-guide is a "Sprung Centre". It's simply a rod 2 or 3 inches long that slides smoothly inside a blind hole drilled deep into the end of larger-diameter shank, with a light compression-spring at the base of the hole, between them. The inner rod has a pointed end or a shallow centre-drilled hole to engage the centre-hole or point as the case may be, in the upper end of the tap.
The tap-wrench is on the tap's square as normal, the spring keeps the guide in contact with the tap. In use the outer rod is held in the chuck with the drilling-machine quill locked at appropriate height, the inner rod locates on the tap's upper end, so holding the tap vertical.
You'd probably find a design in one or another of those various books. Make the sliding rod bi-ended: hollow one end, pointed the other, so you can swap it round to suit the particular tap.
Another refinement is a screw and slot or other arrangement to keep the device together when you lift it clear of the tap.
It is satisfying putting an old machine back into service but be aware that vital spares for what might have once been a very common make, may now be totally unavailable so you'd have to make them.
If it's a lathe with an incomplete change-wheel set you've the added difficulty of finding replacement wheels simply to fill the gaps, because although you can buy stock gears easily enough, you need to know not only the tooth-pitch etc, but also the pressure angle of the originals. I don't know what happens if they are different, but I'd imagine at the least, one set would rapidly wear out the other..
|Chris Vickers||24/06/2019 21:03:44|
|37 forum posts|
And.thank you again Nigel. Well that was a great explanation as I pretty much understood what you were saying, which is something as the sprung Centre was completely unknown as a concept to me....and it sounds and looks great. A quick internet search and I found pictures to illustrate what you describe & eBay showed how relatively cheap they can cost.
Whist being a novice at metal lathe work I do have a fair assortment of mainly BA taps used in my work making and restoring lighting. Very few though have either a point or dimple in the tap holder end. Most are carbon steel, though I'm now investing in HSS ones as I forsee me wanting to use them in steel. Do you think I'd be able to drill the ends of the flat /plain ended carbon taps to accommodate the sprung Centre idea? (or would they be too hard?)
That said the sensitive drill aspect of one of tools/machines seems like it would be necessary for small drills? My Startrite pillar drill is fine enough for the big stuff but would I feel be pretty clumsy for small drills say under 1/8"?
Regarding the change wheels yes I'm sure its an incomplete set. At this stage I'm not too worried about that, if I ever become proficient enough to be able to tackle screw cutting on the lathe rather than taps & dies i figure I'll want to upgrade the whole lathe.
Apart from screw cutting I will only need change wheels to drive the tool post carriage along, different combinations will give different speeds of feed right?
I'm still trying to get my head round pulley ratios along with the back gears, so screw cutting seems a long way off right now! (-:
|Howard Lewis||24/06/2019 22:15:39|
|2207 forum posts|
Chris, coming in late, much of what you need to know has been said. Re Reference Books, as well as Sparey's "The Amateur's lathe" which is heavily Myford 7 Series oriented but very informative none the less. Additionally, Ian Bradley's "The Amateur's Workshop" is worth having.
This Forum is an treasure trove of help, advice.and information.
Tubal Cain's "Model Engineers Handbook" is an absolute mine of information..
When you progress and become more ambitious, ones from the Workshop Practice series are extremely useful for specific items or projects..
(As an aside, Ivan Law's "Gears and Gear Cutting" gets looked at fairly regularly, even when i am nit looking to cut a gear )
No.12, "Drills taps and Dies" and No.3 "Screwcuttinf in the Lathe", should be near the top of your shopping list, and later to be closely followed by Brian Wood's "Gearing of Lathes for Screwcutting".
The more that you do, will bring you experience, and confidence. Even your mistakes will teach you. Hopefully they will not be calamitous or costly.
if possible, find a Model Engineering club near you and join. Again, you will learn from other members, and some may well provide hands on advice and help.
|larry phelan 1||25/06/2019 10:24:47|
|481 forum posts|
Afraid not ! This idea/subject has been covered many ,many times on this forum and the answer is always the same it,s a no go ! The cutter will come adrift ,maybe taking the chuck with it. This seldom improves the finish on the job ,apart from doing damage to both the cutter and maybe the machine.
How do I know all this ? Simple, in a past life, when I "knew it all" I tried something similar [I did not have a milling machine at the time ]. The results were "interesting" to put it mildly. So much so that I never repeated it.
Hold fire until you can afford a mill, such ideas are all part of the learning curve, and I,m still learning.
|Nigel Graham 2||25/06/2019 11:35:26|
|356 forum posts|
There's also a point I don't think anyone else has mentioned, and that is how you would move the work-piece in a straight line in a controlled manner on a drilling-machine! Without that, the cutter could snatch the work with all sorts of nasty outcomes possible.
A co-ordinate vice may seem the answer, but it is not. Many are quite lightly made, solely for locating the work for drilling holes within quite small limited rectangles; they are not for traversing work against a cutter.
I have, once and very carefully, committed the cardinal sin though. I had to drill a lot of simple holes on concentric pitch-circles, on a pair of turned discs. So far so good but two had to be joined into an arcuate slot perhaps 15º "round" X 1/2 inch wide, about 3-1/2" radius
However the material was soft PVC 3mm sheet, sandwiched via spacers on a 6" dia rotary table clamped rigidly to the drilling-machine, and slotted by very shallow cuts and gentle feed.
I would not try it in metal, and certainly not by habit. I ought really have chain-drilled and filed the slots as they are simply the rope anchorages in the side-cheeks of a purely-functional winch-drum.
Why not on the milling-machine? I'd not yet put it into service so was limited to the lathe and bench-drill.
|old mart||25/06/2019 16:04:21|
|439 forum posts|
Which Model of Startrite Mercury do you have? Does it have more than 5 speeds?
If yours has a knurled collar above the chuck, then the chuck is quick change type, and using your lathe, you could make a secure milling head, say er16 collet type. If the bearings are in good condition (no detectable radial play), then the machine should be capable of managing up to 10mm cutters.
Edited By old mart on 25/06/2019 16:19:32
|Chris Vickers||25/06/2019 17:16:29|
|37 forum posts|
Many thanks Howard, I shall look out some of those books and keep some of your suggestions on file for when I progress.
Yes I could not agree more, I've learnt so much for the forum and I only signed up on Saturday, thank you all.
Thank you Larry, yes I shall certainly heed the advice and wait till I get a proper milling machine. I rather like the look of the Fobco Universal and Dore Wesbury's.
Thanks Nigel G2, yes indeed I did think a coordinate vice (that's like a compound slide type right?) would do the trick,.... the more I learn the more I realise I do not know!
Old Mart, I had to go check how many speeds it has...oops! (-:
It has 5 speeds and two knurled collars with holes for tommy bars, does that sound like it qualifies as a quick change? I think the bearings are good. I've seen it written lower the chuck as far as it goes and check for side to side movement. As far as my eye can tell and feel there is no movement. Am I missing something, perhaps it occurs to me now I should put say a Centre drill in the chuck and a cross hair mark on some secured scrap, and then wiggle it, I guess that would be a more accurate test...?.
I would assume for me to make a milling head I'd need to be able to screw cut on my lathe? Gosh that seems a LONG way off right now, I'll have to learn the basics first, interesting though....
Ah now you mention 'say 10mm cutters', I have been wondering what a rule of thumb definition of 'light' milling might be?
|old mart||25/06/2019 18:03:41|
|439 forum posts|
Google "lathes UK" site, find Startrite in the drilling machines column and look in Mercury page 2.
The 5 speed drills with the 2 knurled collars above the chuck are probably what you have. Two C spanners are required, hold the top collar and screw down the lower one against the chuck. Look up inside the chuck, there might be a screw head visible. If there is a screw, it must be unscrewed, most likely a right hand thread. The chuck should eventually drop off, so have a soft pad to catch it.
To refit the chuck, make sure the male and female tapers are clean, and screw the lower knurled collar back up to the top one. Retract the chuck jaws below the body, hold in position and give it a sharp rap with a copper faced mallet. Or use something soft like aluminium to cushion the blow from an ordinary hammer (1lb hammer would do). Refit the screw if there is one.
There are several illustrations of a Morse taper adaptor which screws in place of the regular chuck. When you have more experience of producing threads and taper turning, it would be easy to adapt an er16 collet chuck to fit the drill. 10mm cutters would be the largest size I would contemplate using with your drill.
Edited By old mart on 25/06/2019 18:32:14
|Chris Vickers||25/06/2019 19:46:44|
|37 forum posts|
Thanks for that Old Mart, I just followed that up, and now I know much more than I did about my drill too. Having bought an ER20 collet set which has a draw bore thread in the 1MT arbour it would be great to be able to fit that, if I understand the text correctly my drill should have a 1MT to match. Of course the drills bearings might not like it much and the compound vice would have to be obtained but worth considering.
When I bought the collet set I was only concerned it would fit my lathe, the 20 part of the ER20 meant nowt to me and still dosent. you mention ER16, the the numbers presumably refer in some way to the size of some aspect?
|Chris Vickers||25/06/2019 19:48:34|
|37 forum posts|
Ah maybe you suggest restricting the cutter size to 10mm to protect the drills bearings......
|Nigel Graham 2||25/06/2019 20:29:32|
|356 forum posts|
May I ask why you want an ER chuck on a drilling-machine? To hold a milling-cutter?
Also, though I don't know your particular example, most drilling-machine spindles do not have through-holes so you can't use a draw-bar in them; but many have MT spindles with an internal slot to drive a drill tang.
Everyone's been advising you NOT to use a drilling-machine as a milling-machine, even below 10mm dia cutters. It is NOT made for it, and would a recipe for disaster. The only thing you can use a milling-cutter for in a drill, is to complete a counter-bore first partially drilled to that diameter .
Neither is a co-ordinate- or cross- vice a substitute milling-machine table. Nor is it like a lathe cross-slide, which is designed to take the sideways loads in turning. It is a small drill-vice on top of a slide mounted in turn on another, used solely to move the work-piece between drilling each hole; and taking downwards pressure only. Many of them are very lightly made and of very limited travel anyway. Note what I wrote above: it "... may seem the answer but it is not..." (for milling).
To convert a drilling-machine to a basic mill is possible but only with a lot of precision-engineering, not least including a heavy-duty radial bearing located accurately on an arm fitted to the column to take all the side-loads off the spindle and its bearings. Then you would need a co-ordinate table capable of absorbing milling-type loads.
I admit I got away with a cutting a short arc slot in a bit of plastic sheet, but a rotary-table IS a milling-machine accessory, and I was taking only very light cuts in a very soft material. I also said it was a quick solution to an immediate problem, and I do NOT make a habit of it.
You could build a basic milling-machine, but it's a lot of work. To add to what Larry Phelan said, you are better buying a new or decent second-hand one as large as you can afford by both room and money.
Don't go for the round-colum types though because you have to re-set the centre alignment every time you move the head up and down the column, sometimes several times in making the same part. As I found out! Fortunately there are now available even quite modest milling-machines with dovetail columns, and many people seem to find them very satisfactory.
|Chris Vickers||25/06/2019 20:39:28|
|37 forum posts|
Thank you Nigel, understood! (-:
I much appreciate this.
|Dave Halford||25/06/2019 21:00:09|
|438 forum posts|
How times change, Mr J.G. Churchill in Model Engineer 15th may 1981 number 3657on pages 624 and 625 has cut the gears on the Modular traction engine using a home made single point cutter mounted in a B&D drill
|Howard Lewis||25/06/2019 21:24:26|
|2207 forum posts|
The ER20 collets,will hold upto 13 mm diameter tools ( drills, End Mills, slot drills ) but I would advise against using milling cutters in a pillar drill.
Extended Range collets are useful, in that they can cover a range of 1 mm, and are so marked. Consequently, they can hold Imperial as well as Metric cutters, within that range.
As an aside, it seems that the 1.5 mm pitch thread of the closing nut takes its size from the next size up, i e. ER 20 would have a 25 x 1.5 thread.
It has been said many times that the bearings in a drill are unlikley to have been designed for anything other than axial loads. Trying to use a pillar drill as a mill is likely to damage the machine, and probably the cutter and the workpiece, possibly even you as a guilty by stander!
You can mill in the lathe, but it is not as rigid, nor have as big a range as a proper milling machine. Although, for a very limited range of work, a Vertical Slide can be useful.
If you want to mill, save up and buy a mill, not a co ordinate table.
I have an elderly round column mill/drill, and having to realign the head every tome that it is raised or lowered is a right PITA. A dovetail column machine would save me the trouble having to use a laser to align things, but I don't know of one with Imperial leadscrews and dials.
|Chris Vickers||25/06/2019 21:38:41|
|37 forum posts|
Thank you Howard, yes I will save up for one....I have no desire to damage my drill or me! There is so much to consider with it all, and of course you can only consider it if you are aware of it! (-: I guess some will become clear in time.
I understand about the round columns i find it similarly frustrating with the pillar drills round column.
Thinking of space(lack of) I suspect for reasons I don't yet know a milling machine dosen't make a good drilling machine either? Perhaps they don't take Jacobs type chucks....
|Nigel Graham 2||25/06/2019 22:30:48|
|356 forum posts|
" Thinking of space(lack of) I suspect for reasons I don't yet know a milling machine dosen't make a good drilling machine either? Perhaps they don't take Jacobs type chucks.... "
Ah, now, you CAN use a milling-machine as a precision drilling-machine; co-ordinates and all.
In fact a typical milling task may involve drilling and tapping several holes as well as squaring the outline to shape and size, cutting slots etc., all in one piece of metal.
No, they don't take Jacobs chucks directly in the spindle. Instead, the chuck fits onto a special adaptor with the Jacobs nose and an appropriate taper shank with internal draw-bar thread to fit the spindle; and it stays on the adaptor. You remove the adaptor from the mill, not drill-chuck from adaptor.
Just make sure you don't spoil the machine by drilling too deep and into the table!
Milling-machines generally don't have a chuck as such, like a drilling-machine. Instead the cutters, drill-chucks etc are held by interchangeable tooling that fits into one of various standard types of spindle taper. The two standards you and I are most likely to encounter are:
Morse (MT3 being perhaps the most common for model-engineering milling-machines).
R8. This was the standard on Bridgeport milling-machines once very common in the engineering trade, and on the Myford VMC mill. (The one I have)
You might encounter ISO - number; the modern industrial standard particularly suited to high-performance CNC machines. I don't know if any of the model-engineering trade machines use them: some of the larger, latest might.
New and second-hand Morse and R8 tooling is quite easy to find. The advantage of R8 is that the taper is steeper than Morse, so much less likely to jam in the spindle; but Morse tapers means some tooling is interchangeable with other machines, like most small lathes.
You can also add to milling-machines, accessories like vices designed for that task, rotary tables for cutting arcs and drilling accurately-spaced rings of holes, and angle-plates which at their simplest hold a work-piece on its side.
On-line catalogues like those of Arc Eurotrade have photos of milling- (and other) machine tooling, as examples.
|not done it yet||26/06/2019 06:54:05|
|3236 forum posts|
The one advantage of a pillar drill, that Nigel perhaps omitted, was that of height available between drill bit and table. Floor standing options will accept seriously large sized items, while bench mounted ones are ‘similar’ to most hobby milling machines.
My larger mill has a spindle nose to table distance of around 425mm (rather less if a Jacobs chuck is fitted), but that figure has been increased (from standard) by adding a 120mm riser block to my machine (check out the current ‘Centec’ thread). My smaller mill only has 213mm head space, so often needs an alternative holder to a jacobs chuck, may need to use an alternative to using a milling vise for workpiece holding - as well as choosing a stubby drill bit! ‘Horses for courses’ is the order of the day.
Edited to add that if I don’t have enough head space, other alternatives are a hand-held drill (perhaps on a drill stand) or a heavy duty drill with magnetic base
Edited By not done it yet on 26/06/2019 06:59:58
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