# myford drilling of centre



## fcheslop (Apr 29, 2010)

I have a problem with my old ML7 and wonder if anybody has had the same. When drilling deep holes in small diameters the hole never drills true always comes out to one side and if the hole is very deep it can come out of the side of the job sorry if I'm not being very clear.The machine has recently had new bearings and mandrel fitted but the problem existed before and has not improved.Have set the machine up with a test bar between centres and clocked in using a test bare fitted into the headstock it will turn true and bore true but Will not drill true.I know I'm probably missing something simple but cant find it .The tailstock has been stripped and no burrs or any problems found in the casting or barrel.Its always done this since i purchased it but is now becoming a problem due to wanting to make ever smaller parts. The machine is mounted on a sturdy wooden bench that does tend to move with the change in humidity but I always set it up for doing accurate work and can turn 14 inches to within a couple of tenths 0.002 and bore to the same accuracy or as near as i can read my mikes scale.I withdraw the drill often when drilling but some times i think i see the drill bit dipping as it starts the smaller the dia the worse the problem I've also used different drill chucks?.My test bares where made on precision centre grinders and if i test between centres on the lathe there is no radial run out either at the head stock or tailstock Istill think it is something simple I'm missing but now have no hair left to pull out.Any help would be appreciated.
regards Frazer


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## tel (Apr 29, 2010)

Sounds like the tailstock is out of alignment to me - put good clean centres in headstock and tailstock and see if you can nip a razor blade between 'em without it tilting


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## Blogwitch (Apr 29, 2010)

How large are the drills you are using? and as Tel says, make sure you always start off with a good centre point.

If you are heavy handed, and don't 'peck' the holes out, you are just liable to end up with the drill almost coming out of the side of the job.

I can get away sometimes with putting a 1" drill thru, and not having it go off centre. Anything smaller, and I will always peck drill.


Bogs


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## don-tucker (Apr 29, 2010)

What I did to check the tailstock was mount the dti on a bar in the headstock chuck and test around the tailstock barrel also with this setup you can check the barrel for being parallel.
Don


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## fcheslop (Apr 29, 2010)

Thanks gents,Tel ill try that when i get of punishment duties[gardening] If the tailstock was out would it not machine a taper just a question
          John the problem rears its ugly head below 3/16 and get worse, I'm currently trying to drill holes from no60 to 75 and at this size of hole you have to be careful as you know theres usually more swearing than cutting fluid.The lathe has always had this problem i bought it 30 years ago and it was made in 1965 and was only used in a scientific lab but may have been abused who knows.Just a little background i work/worked on precision cnc and robotic equipment and made the test bars on these grinders so i know they are accurate just so you know its not some hairy a-sed fitter trying to force a 3inch drill through some rough plate :big: but the problem is becoming a pain and I've seriously considered replacing it but it feels like putting the dog down and it cost £200 for the new headstock mandrel and bearings but maybe i should just cut my losses but i don't like giving up.I'm certain its got to be some thing daft I'm overlooking
          Don, Thanks I will try your suggestion
Thanks again gents will update if/when the problem is found or sit there broken hearted :big:


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## JimM (Apr 29, 2010)

I had/have a similar problem on my old Atlas lathe. I've managed to get it better than it was but I've tweaked so many things I'm not entirely sure what worked ! I suspect the problem was with the tailstock taper, I've given it a light ream and that seemed to make thing better, when I get a chance I'll try again and will report back

Cheers

Jim


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## Jasonb (Apr 29, 2010)

Can you mount the drill chuck in the headstock and test it for run out? As you say its OK with a CTr in the tailstock it may be the drill chuck thats out.

Jason


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## fcheslop (Apr 29, 2010)

Thanks, Jason ive already tested the chucks and they seem ok just spent the last couple of hours looking round again cant find anything obvious so going to completely strip it and start setting up from the begining its due a good clean up .
      Jim hope the Atlas goes well.
regards frazer


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## chipswarf (Apr 29, 2010)

A technique I've seen recommended has you start the hole undersize, then open to just the planned drill diameter with a boring tool, D-bit or end mill, to guarantee straightness and concentricity. This serves as a guide for the full diameter drill.

In older texts, it's often shown how to stabilize the entering drill bit by side loading it with something from the tool post, like a backward tool holder. If you orient the drill cutting lips, they can cut as a supported boring tool and give the same result.

Mark


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## New_Guy (Apr 30, 2010)

it sounds like a very simple common problem your tailstock bore is worn you say the machine is 30 years old so its no surprise

as i understand it when you buy a new lathe the tailstock center should be a touch high this really wont have any effect on turning so its not noticeable and its so as you use the machine the center will slowly lower as the tailstock ram (quill) wears in the casting from gravity and the like i would bet my 2c that thats a factor in your problem unfortunately you cant fix it other than by boring out the casting making a new ram 

have you thought of maybe making a sort of drilling/high speed drill tool for your cross slide? having the T slots would make a tool like that very handy and you can make sure its dead on it may help who knows


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## Blogwitch (Apr 30, 2010)

NG, 



> unfortunately you cant fix it other than by boring out the casting making a new ram



Not quite correct, I rescued my Atlas tailstock which had a droop snoot.

http://www.homemodelenginemachinist.com/index.php?topic=2114.0


Bogs


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## lordedmond (Apr 30, 2010)

you say ML7 and with your comment on the price for the new shaft and the bronze bearing that have replaced the soft shaft and babbitt I am assuming so

its the design of the tail stock you have the non ejecting one with the screw through the hand wheel they get sloppy , a ML7 super on will fit and will improve your problem . when you replaced the bearings did you replace the thrust bearing as well ?. I had the same problem but not as bad , I to replaced the bearings ect , gave up in the end and dropped a load of dosh £7K plus on a new blue job from my local supplier ( Myford ) only six mile down the road this one will drill correctly.the 1 inch bore on the mandrill is a joy . ;D

BTW a mate has fitted a super 7 TS to his 7 and his drill straight no problem
as a final point have you tried the Dormer PS point drills http://www.greenwood-tools.co.uk/ishop/728/shopscr81.html


Stuart


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## fcheslop (Apr 30, 2010)

Thanks again,Food for thought i have started to make a mill/drill unit for the cross slide with a micro feed but am holding off finishing it until the lathe is working to my satisfaction.Thanks for the link Bogs.Stuart you are correct about the type of tail stock fitted but if i where to put 7k into messers Myfords hands although i would love to my personal financial adviser [Mrs H ] would remove some much loved delicate parts from my anatomy :big:
regards Frazer


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## lordedmond (Apr 30, 2010)

You are thinking short term a new lathe will last you a lot longer after the other parts have ceased to function :big:


Hope you get it sorted the drill quoted do help a lot you will not believe how the drill no effort required , they will outlast the cheaper one by about 10 fold



Stuart


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## New_Guy (Apr 30, 2010)

Bogstandard  said:
			
		

> NG,
> 
> Not quite correct, I rescued my Atlas tailstock which had a droop snoot.
> 
> ...



man thats a good idea it would sure be better than boring such a long hole and making a new ram lol i noticed it had a white lead hole how old was it? you wont get that use out of these new lathes lol


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## fcheslop (Apr 30, 2010)

Well Gents, I have to hang my head in shame and go to the back of the class it is wear in the tailstock body 6thou at the front of the casting a repair is not possible at the moment so I will have to consider what to do either buy a new smaller machine or Waite until I'm In a position to re machine the body as per Johns article.Currently kicking myself for missing it in the first place [call youreself an engineer answer muppet] but the most important thing with the help of the forum it has been found and I sincerely thank all who took the time to reply.


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## Blogwitch (Apr 30, 2010)

fcheslop,

Nothing to be ashamed about, sometimes you can't see the forest for all the trees that are in the way.

At least you have now found the cause, and at a later date, you can do a fix or if pennies allow, buy a replacement.

NG,

I never used the white lead pot, as invariably I used cutting paste when using a solid centre. Supposedly, as far as I could trace, the lathe was made sometime in the late 30's. as it came across the pond on the lease/lend contract, to help with the war effort.


Bogs


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## don-tucker (Apr 30, 2010)

No need to "hang your head in shame" I went through all that and put the good guys on here through a lot of aggro to find it was a burr my son had kindly donated.
Don


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## lordedmond (Apr 30, 2010)

fcheslop  said:
			
		

> Well Gents, I have to hang my head in shame and go to the back of the class it is wear in the tailstock body 6thou at the front of the casting a repair is not possible at the moment so I will have to consider what to do either buy a new smaller machine or Waite until I'm In a position to re machine the body as per Johns article.Currently kicking myself for missing it in the first place [call youreself an engineer answer muppet] but the most important thing with the help of the forum it has been found and I sincerely thank all who took the time to reply.



Glad you have found the root cause of the problem. I was going to suggest that you put your test bar in the tail stock and see where it points to 

Just for info I have just come in from drilling a 5/32 hole in 316 SS 4 1/16 inches deep so deep I had to pull the tail stock back to clear the chips , result dead centre at the other end 

If I where You I would keep my eyes open for a super 7 tail stock they are so much better


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## fcheslop (Apr 30, 2010)

Hi Stuart. Going to have to consider the options 1 spend the money at Myford and loose some soft dangly bits
                                 2 spent the kids inheritance with above consequences
                                 3 repair my old banger more likely and less painful
                                 4 find a good s/hand tailstock
                                 5 find the combination to Mrs H purse this I know is impossible
Ive stripped and cleaned the lathe today and its in reasonable working order so will just have to plod on until an alternative becomes available was thinking of a new small lathe but after reading so many threads about alignment problems just not sure what to do but intend to have a look at Harrogate show to see whats available as my milling machine is now well past its best after 24 years of abuse having had all sorts from Honda CX500 motors to large lumps or steel milled on it.I think in the near future its simply going to be time to re invest in some new kit better than giving it to the bankers i suppose although a nice Thruxton Velo might sway me :big:thanks again


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## New_Guy (Apr 30, 2010)

its good to hear you found the problem now you know whats wrong you can try and avoid it or at lest compensate it i wouldn't go out and get a new lathe you have a quality lathe that works for you and another project have you got an adjustable boring head? sounds to me you could maybe do it all on the lathe and you have a mill thats great don't let it phase you maybe take a few afternoons to plan out what to do and carefully give it a try 

also that wear happens to all lathes yours is 30 years old its no surprise there was a big talk over on PM about wear on lathes sparked form a box way Raglan lathe the conclusions were that box ways were far easier to fix, stayed very accurate in the middle channel and that on all used lathes the tail stocks usually have/cause the most wear both to the bed and to the ram we use them so much and most dont have wipers it just happens with out us knowing it you are luck to have a Myford i bet if you fix this it will last another 30+ years with out any problems


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## Blogwitch (May 1, 2010)

Frazer,

Have a look at my signature line.

I was getting myself really worked up when it came to machining mine, putting it off all the time, but eventually it got so bad, something had to be done.

There are few different solutions that people came up with in my post, and looking at it, maybe my method was the long way around the job, but for me, it was the right way for me to go. I am sure that one of the other methods would have had just the same good results.

After it was all done and dusted, I sat there looking at it and thinking, 'what was all the worry over'. A few hours of fine precision working saved me loadsa money and gave me loadsa satisfaction.

You have nothing to lose, the tailstock looks to be of no use as it is. If you make a rat's a**e of it, you have lost nothing other than a few hours of your time and a bit of material.

I honestly wish a few of you lads with problems such as this lived a little closer, I would come across and do the job for you. I have done it for a few people who have mini lathes, they brought them to me, but a Myford is just a little too large to bring over. But if it is worn in the same place mine was, then there is no reason that I couldn't do it with just the tailstock here, using the bedway slides and ram for reference points.

We will discuss it if we get to meet at Harrogate.


Bogs


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## fcheslop (May 1, 2010)

Hi Bogs, just read and re read the tailstock post I don't see any problems machining the tail stock as you did yours but don't have a decently large mounting plate but as per your signature will have a go in the near future.The scary part is its my only lathe and my backside will be phutting penny washers.Correct me if I'm wrong the Myford clamps the tailstock spindle from below so this should be OK to lock the test piece for clocking in on the mill unless it'll go on the cross slide or vertical slide.Think the first job is going to be to give it a good looking at .Most of my kit is now getting past its sell by date and accuracy is becoming an issue the mill was bought in 1984 and has done a lot of work despite being a cheap Taiwanese import that was much slagged of in the press at the time by you know who and at the price of the new ones is hardly worth rebuilding but the Myford is a different matter so any help is appreciated .Time at the moment is not a problem spending larges sums that may be irreplaceable is if you get my drift.Looking foreward to meeting up on Saturday just keep an eye out for the overweight bearded guy cutting the straps on those bloody haversacks they wear and IL follow the sound of the high pitched Bogs victims we should meet up eventually or ill see you at security awaiting an escort from the boys in blue.
regards and best wishes Frazer


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## New_Guy (May 2, 2010)

you dont have an angle plate big enough? make one just go to your local fab shop and ask if they could do you a small job for cash of a case of beer then take home your welded angle plate and machine it true you could even machine a key way so your tailstock slots in and then it wouldn't need much clocking


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## fcheslop (May 2, 2010)

Thanks for the advice, have given it a couple of coats of looking at and think but not yet certain that it can be mounted on a My ford vertical slide using the cam lock holes clocked in then after bending my partner in crimes arm up his back borrow his tail stock and use this with a between centres boring bar the reason I'm looking this way is that i wish to re bush the rear of the tailstock where the handle runs as well as the front might as well kill two birds at the same time.
regards frazer


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## New_Guy (May 4, 2010)

sounds like an idea


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## fcheslop (May 12, 2010)

Hi all ,Back on this problem again re bushed tailstock as per Bogs article the machine is now within 1thou when checked in all directions and the tailstock sits 1/2 thou high with the barrel fully extended.I was going to post pics in another thread but still learning how to use photo shop etc.The machine will still not drill a parallel hole and the smaller the drill the worse the problem but when centre drilling using a clock as best as possible only get 0.0003 deflection .When drilling the hole the drill bit is widthdrawn approximately every 1/32.I have to say that it now definitely starts a centre drill a lot better and drills the larger holes to a far better degree of accuracy but just cannot find the problem with the smaller sizes any help will be appreciated before either it goes to the skip or I end up in the nut house.
regards Frazer


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## fcheslop (May 12, 2010)

just tried drilling ten pins all 1/8 OD with a 1/16 hole using different tailstock chucks and two different chucks on the headstock all pins 1inch long when measuring at the max run out all the pins have a wall thickness of 17 to 19 thou.Gone right back to basics checked /blued of tail and headstock tapers all OK rechecked alignment and for twist all OK rechecked machine level every thing to within 1thou. Running out of ideas [ranout].
regards Frazer


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## lordedmond (May 12, 2010)

have you tried using a collet chuck 1/8 dia is a bit small for a normal 3 jaw chuck


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## Blogwitch (May 12, 2010)

Frazer,

I know it might sound silly, but I don't think you have mentioned if your three jaw has any runout in it.

The action of a small drill trying to drill a component with an elliptical motion will give almost the same results as you are getting.

The thin drill will follow the elliptical motion, even if you have centred it. A more rigid drill will stay on centre much better.


John


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## fcheslop (May 12, 2010)

Hi lordedmund, tried collet chuck and even just a plain drill chuck the baffling thing is the run out is near constant on all pins, now been on with this for 2 days in total and still no better looking decidedly dodgy for some anatomical components :big: just so frustrating this has always been a problem with this machine .I am going to try the tailstock on another ML7 to try and find out if it is the tailstock or something else just at the stage of not seeing the wood for the trees but convinced its something simple but what.
Hi Bogs, run out about 3 thou at 1/8 chuck jaws parallel
regards Frazer


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## lordedmond (May 12, 2010)

If its always been a problem, then it must be a fault with the basic setup of the headstock, bed and tailstock

what does a morse taper test bar indicate in the headstock ( no chuck fitted )
the same test bar can also be used in the TS 


Stuart


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## dparker (May 12, 2010)

Hello All: I have had the same problem with deep drilled holes wandering off center also. I improved the problem by doing the pecking thing and cleaning the bit off with a toothbrush and cutting oil each "peck" (it did help quite a bit).  One thing I did not see mentioned was the point of the drill bit being right in the center of the drill. I took some time and sharpened the bit (granted, quite a bit larger than 1/16" dia) and tried to make sure that both cutting lips were the same length, this improved the problem somewhat more when both lips were cutting. I could be just fooling myself and your mileage may vary but good luck, a interesting thread and I will attempt to apply the helpful answers in my shop also.
don


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## fcheslop (May 12, 2010)

Hi Stuart , The machine has been checked with Morse test bar and wound in ,then checked with a between centres test bar,spindles both ends have been clocked, max wear on bed ways is 2 thou all other measurements have a max run out of 0.001 as set.The machine will turn a 18inch bar to within 2 tenth parallel and will bore a hole true enough that I cannot measure the err. I have had my test bars recently checked and they are within 2 microns and this is the tolerance I made them to when i used to work in precision engineering .The problem has only become a nuisance in the last few years as I no longer have access to precision machines[looks like next job some where with decent kit] and at the moment I need to make some very small parts for an engine 1/16 bore and 1/16 stroke daft I know so I have found some hypodermic needles and am currently thinking of using these for the cylinders and pistons previously they would have been sparked. The next job on the lathe to find out where the problem lies so I am going to try the tailstock on another machine To be honest this has always been a problem on this machine and never seems to improve and is peeing me off to put it politely and would love to bin the machine if I could but don't know what small machine to purchase to run along side it .Thanks for the advice keep it coming we might just hit lucky.Think I will have to start making larger models maybe even as big as Poppin :big:       
Regards and Thanks to all Frazer


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## billmac (May 12, 2010)

Myford series 7 tailstocks get their side to side location from the two inside edges of the bed. Unfortunately the wear on these faces can vary down the length of the bed so that the tailstock can be aligned straight at one point but not in other places. I assume that you have adjusted the base of the tailstock to make the best of this situation which is an unfortunate design feature. A few degrees wander in the pointing of the tailstock can cause a drilled hole to wander a lot further out, particularly for deep holes and smaller bores. To check this, look for angular free play, after you have adjusted the tailstock as well as possible.


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## fcheslop (May 13, 2010)

Hi Bill, Thanks for the advice this has also been tried and the bed tested and is parallel to with in 2thou.Just going to live with it for now as life's to short but will try and eliminate tailstock today or tomorrow then work from there as a the moment I just don't know for certain where the err is coming from and am becoming a bit like the fufu bird :big:.Thanks to all for the help will post if/when i find the problem.
regards Frazer


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## fcheslop (May 13, 2010)

Hi again.tried the tailstock on another ML7 and it drills a 2inch deep test hole bang on centre so hope fully this proves the tailstock and my repair ?.Next will try to find out if the problem is in the headstock is it vertical or horizontal err by marking the collet and piece then seeing which way its wondering when drilling but not certain yet how I am going to test the spindle in relation to the bed if you get my drift.lt will be nice to actually find something obviously wrong ha I wish
regards Frazer


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## lordedmond (May 13, 2010)

bet its the vertical alignment of the headstcok bearings as you have now eliminated the TS so it can only be the HS 


try putting your test bar it the mandrel and using a hight gauge from the bed way as you know the bed is OK 

Stuart


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## fcheslop (May 14, 2010)

Just to say thanks to all for the advice.Stripped and checked headstock on machine no problems found the hole machine has now been totally stripped and checked and the max run out is 2 thou but still wont drill true.As i have said before this machine has always had this problem but from time to time it nark's the hell out of me.Going to start looking to replace or buy another to run along side it any advice on a small but accurate machine gratefully accepted but not a Myford :big:
regards Frazer


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## lordedmond (May 14, 2010)

for the cost of a phone call why not ring Myford up , they may be able to zero you in as to the problem with your lathe. the sales man is Malcolm and the sen fitter is Brian

don't be put off with the term salesman Malcolm knows these lathe inside out 

as you have checked the thing from top to bottom and found no errors , your job will have given you the correct methodology to test out the lathe, Sorry I have no more ideas to help you sort out the problem

Stuart

note they shut at friday lunch for the weekend


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## fcheslop (May 14, 2010)

Hi Stuart, Will give them a try but have spoken to them before several years ago and drew a blank then. You would think some thing would measure out. I remember when I bought it there was an old machinist at the place and he said he could never get on with it you know the type brown machine coat ,rolley behind the ear and that knowing look maybe he was trying to tell me something :big:. Will post if anything comes to light .Just been looking at a new Cowell 90 didn't realise they cost so much new. I shouldn't have sold my Boley but we all do daft things cheers and thanks again to all.
regards Frazer


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