Member postings for Graham Meek

Hi Mike,

While a level is the quickest and easiest way to check for twist, it is not the only way.

In my first post I outlined the use of a length of Silver Steel or Precision Ground Mild Steel. I used this method to set up my Maximat lathe the last time I moved the shop around.

I bought an 8" Engineers level second hand form an advertiser on here. It is a Rabone and Chesterman circa 1970's. I don't know what accuracy it is, but it is fussy. When I checked my lathe with this level I found it was not that far out, given I had used the Ground bar test.

Unfortunately I am the other side of the country in the Forest of Dean, or you could gladly borrow my level.

Regards

Gray,

Hi Will,

The travel to trip the clutch at the carriage, on the Myford, and the Hardinge I worked for some time was about 15 to 16 mm, from memory. The travel at the S7 and ML7 clutch units is 2.5 mm, the clearances need be no more than 0.25 mm. The Operating lever stops moving as soon as the Dogs disengage, and the ball bearing detent wants to be close to the neutral position, so that the Operating lever will snap into neutral.

Once set the carriage will repeatedly stop in exactly the same position and start in the same position. The only time these settings alter is when you set at a lower speed and then for some reason increase the spindle speed. As you rightly assume it is to do with Moments of Inertia, but once the settings have been reset at the higher speed the carriage will carry on as before.

I have always pointed this out when setting up the clutch unit in my articles to make those wary with VFD drives. It was something I found out while using the Hardinge which has variable spindle speeds.

Regards

Gray,

Hi Will,

I am really glad someone else has picked up the screwcutting clutch gauntlet and is running with it.

I am currently starting to put together a version for the Atlas 618 lathe. Thanks to an enquiry from the USA. This has been proving to be one of the hardest to do, due to the peculiarities of how the screwcutting gear train takes its drive, depending on TPI, from one of the two gears on the tumbler shaft.

I did think to start with that this would be a reworked version of the ML7 due to the similarities between the two machines, but I was wrong.

My Maximat clutch design last year was I thought going to be my last design in this field. I am beginning to know how a type cast actor feels.

I wish you well with the design, and if I can be of any help, don't be afraid to ask.

Regards

Gray,

Hi Mike,

Thank you for the kind comments about the Handwheel Dial. Steve makes a better job of them than I did, he has the kit to do it with.

Generally

As regards using an Engineers Level with a worn Flat Bedway. It is known that the wear on this particular Bedway is 0.0025". A feeler blade, which is a standard in my Moore & Wright set of gauges, can be interposed between the Bedway and the Level which will restore the Status Quo. No need for any further dismantling, or ruling out the use of a Level to check a worn bedway.

Regards

Gray,

Edited By Graham Meek on 25/05/2020 10:19:06

Mike what sort of tool are you using?

I use only a well honed HSS tool for machining test pieces after checking or resetting alignments. The type of tool and depth of cut are going to greatly influence the results. I limit the depth of cut to 0.05 mm or 0.002", this standardises the machining conditions.

I do think you are asking a lot of the Myford as regards the unsupported length, which I take to be 100 mm or 4". As you say you have 1" in the collet. On my Emco Maximat Super 11 which has a taper roller bearing headstock I only ever use a 75 mm protrusion of the test piece beyond the jaws of the chuck.

Personally I would start with the test bar in a spotless mandrel socket and run a clock along where a tool would normally pass and over the top. The latter test will tell you if the spindle is dipping or pointing skywards. The first test tells you whether the spindle is pointing down the bed centreline.

Provided you have not disturbed the headstock casting during your overhaul?

Then if the clock in the tool position is reading higher or lower towards the tailstock end then the bed is out of alignment.

To set this I either use an Engineers Level or a piece of 25 mm diameter silver steel kept specifically for the purpose. Grip one end in the 4 jawed chuck using protection pieces and clock to run true. Check the outer end and any high spot should be put at the top.

Return the clock to the tool position on the Silver Steel and clock from headstock to the tailstock end and adjust the bed feet until you get the same reading.

Remove this set-up and return to your test piece. It should not be that far out and minor adjustments to the bed feet at the tailstock end should put it right. Two collars on the test piece save a lot of time machining and preserve a HSS cutting edge.

Spot on concentric centres in the piece of Silver steel make setting the tailstock a doddle.

Regards

Gray,

Hi John,

The straight knurl here was done with a single wheel straight knurl. While it is not as crisp as Martin's or Steve's it comes a close second. After making 500+ Myford handwheel dials using the same technique I thought I would share with you how I do this.

I never knurl a dial after the graduating, and the knurled diameter is always lightly skimmed. The skin of barstock is not the best thing for knurling wheels.

The Knurling wheel is set in the toolpost such that the wheel is canted towards the tailstock by a few degrees. This way the leading corner of the wheel is touching the work first. Prepare the knurled portion and have a chamfer at the beginning and the end of the to be Knurled surface.

For a 5/8" knurl I usually run at 65 RPM for dials of this size. The feed is about 0.1 mm or 004" per rev. Make sure the knurling wheel is absolutely clean. Touch on the diameter with the knurling wheel and then move towards the Tailstock. Put on a cut of about 0.2 mm or 0.008" deep. Engage the feed and apply a drop or two of cutting oil, preferably out of an oil can, and never with a brush which has been used for turning. The brush will not only end up in the knurl but it has little bits of swarf that will damage the knurl.

It may take a couple of cuts to get close to depth. Finally put the knurling tool in the toolpost square on and present to the work with the work revolving. Approach slowly so that the knurl can pick up the work. If you are not happy doing this just bring the knurling tool up to the stationary work and with your free hand just work the knurling wheel back and forth until it engages. Start the spindle and continue to apply light pressure. Move towards the tailstock but be sure to keep the knurl engaged. Re-engage the feed but at half the original feed rate.

Using the chamfer tool clean up the chamfers to remove the displaced material.

As regards Blacking.

I use Curator Antiquing Fluid for Brass, Copper and Steel. De-greasing is paramount and I use Isopropyl as a first step with an old toothbrush. Followed by a wash in warm water which contains washing-up liquid, followed by a warm rinse and a quick dry with the airline. Before immersing in a solution of 10% Curator and water from the workshop dehumidifier. It takes 2 minutes according to what it says on the bottle. I have to admit I was sceptical about this but it does exactly what is says. If trapped air bubbles form on the knurl give it a rub with a clean old toothbrush. The part is removed, rinsed in water and blown dry with an airline before being given a coat of Shell Enisis.

The Dial above has been in service for quite a while now and shows no sign of deterioration of the blacking. The bulk of the Curator Fluid bought is still in the bottle ready for the next big item. The made up solution is kept in an air tight container and is still usable for blacking small parts, nuts, bolts etc.

Regards

Gray,

Ketan has in my experience always given good advice. Whether that advice is taken depends on the person it is directed at. I have known such good advice being shot down because of bias against ARC over some previous issue by a poster. Nine times out of ten the biased advice is somewhat dubious.

How do I know good advice?

Well 5 years as a Technical Apprentice at Dowty's. 30 years as a Toolmaker in jobbing shops and 10 years as Head of the Mechanical Workshops, The Oncology Centre, Cheltenham, has given me the Experience to know.

All that I have purchased from ARC has been of good quality and appropriate for the money paid. It cannot be easy trying to bring tooling and machinery to the market place at a price which people are prepared to pay.

I had better add that I too have never received any payments in kind, or otherwise, for any article written on behalf of ARC.

Regards

Gray,

Hello John,

I don't think you need worry about cracks now, and like you say, "a worthwhile precaution".

Regards

Gray,

Generally,

There seems to be a a problem as I take it, with the title of the PDF Drawing. There are in my AutoCad files several R8 Spindle drawings, not all are for milling machine spindles. I know by this title exactly which it is.

No doubt had I have given this PDF the Machine model number, as well as those for the associated variants, I may have upset a whole load of trade suppliers. Some of whom do not seem to suffer with this problem.

Regards

Gray,

Nice work Martin, you have been busy since we last spoke.

Regards

Gray,

Hello Richard,

I was fortunate to work a brand new HLV lathe. for 7 years, but that was 40 years ago now, so my memory is not so good. There is a round knob near the rear of the headstock which will select the threading box. The quadrant on the outside of the box is only used for Imperial and special threads, like DP or Mod or additional Metric not covered by the box.

One point to make when setting up for threading is to set your speed first. Increasing the speed alters the trip point on the screwcutting clutch. It is all to do with moments of inertia.

From what I recall there is a sizeable two speed motor on this lathe. In use it is possible to go from high range directly to low range, this might cause some invertors a problem. I know of one person who used a rotary phase converter.

Is your machine fitted with a handle to alter the variable speed, or does it have a separate motor like the one I worked on. If so I suspect this motor will need to be accounted for with the sizing of any invertor. Plus there is the variable DC power feed to the carriage for normal self acting feeds, this too will be a load on the invertor. No doubt the more knowledgeable electrical Forum members can help there.

Regards

Gray,

Hi John,

You are indeed fortunate the spindle is not that hard. The 4 mm should suffice provided you don't over tighten the drawbar. For peace of mind an additional collar could be fitted with Loctite 630 or similar. I would however put a large chamfer on the exposed corner to allow better vision when using small cutters with an R8 collet.

Regards

Gray,

Hi Michael,

I purposely did not provide any details of the internal taper as this spindle can be had with a Morse taper as well. Plus the outside dimensions were all I took at the time. Had it been necessary for me to make my friend a new spindle. Then I have the details of the R8 socket on file somewhere.

Regards

Gray,

I eventually found the rough sketch I made of the defective spindle which was eventually salvaged. Just in case anyone finds themselves in a similar position and need to make a new spindle I have uploaded a rather poor Jpg drawing.

If there is a requirement for a better image of this drawing then I can furnish a PDF. If there is a method to make this available to the Forum, this would save a lot of exchanges of emails. Perhaps Neil or Jason can help here?

Regards

Gray,

Hello John,

I have sent you a PM

Regards

Gray,

Solid edge is not working on any of their options, I was trying yesterday.

Off topic I know, but such forms handed out at NHS visits are to satisfy the tick box. Plus good ratings are used to outweigh the poor ones, yes these are sad I know. My Father fought cancer for 30 years, he received nothing but the highest care. This was one of the reasons I joined the NHS for 10 years in the twilight of my career, I wish I was able to assist now.

Regards

Gray,

Hello John,

There is one YouTube video posted which shows a non-QC gearbox installation. While it is on a standard Super 7, there is little difference between this and the ML7R. The video was posted by a friend in Italy who I helped out many years ago.

Thanks Phil and Brian for answering on my behalf, I do not always log-in every day.

Regards

Gray,

The taper roller bearings on my Emco Maximat Super 11 have yet to be adjusted. The machine was purchased new in 1986. It has seen a lot of work, for 10 years I worked from home and this machine earned my daily bread.

According to the Emco Manual the headstock bearings are adjusted so that the spindle makes one complete turn after being pulled around smartly by hand. All gears are in neutral, as is the drive to the quadrant gears.

For my part I would be checking the slideway adjustments. All slides should be able to be moved by hand pressure alone and they should never be adjusted with any feedscrew in situ. A clock on each slide element would be how I would assess if there is any play present. Starting with the topslide and working down to the carriage to bed interface. Ensure the clock is only clocking between slideway elements. A clock for instance held in the chuck and detecting play when pressure is applied to the toolpost, can be detecting play in any one of three slideways.

The Harrison lathes I have worked on during my career have always produced good work, I hope this helps

Regards

Gray,

Hi Trevor,

From what I can see in the tailstock housing photo the thread seams to be full of small particles of swarf.

One thing I would do is with a single point internal screw cutting tool, is to clean out the thread with this. A single point tool used methodically will show up any defect in the thread which can be scarped away using the tool.

Then it needs to be clean, really clean. Start with an old tooth brush dipped in white spirit regularly. Mop up the accumulation from the bottom of the bore as you go, don't allow this to flow towards the tailstock barrel. If you have, Isopropyl, brake drum degreaser use this with the tooth brush afterwards, but watch the paint on the body of the tailstock. It might be wise to wrap some masking tape over this and around the edge to protect it.

Finally with some cotton material from an old Tee shirt, wrap a strip several times around a piece of small diameter, plastic, or steel bar. Work this around the thread to remove the last bits of debris. This might need doing several times.

My hunch is the female thread is at fault, but just to be on the safe side, put the male housing on a mandrel in the lathe. Running in backgear with a half round Swiss needle file run up the flanks of the thread using the flat of the file. Then pay attention to the crests of the thread again with the flat of the file. You are looking to remove damage not a load of material. Coating the thread with felt tip marker will show where you are taking material/damage off.

Don't be tempted to use a 3 square or Triangular Swiss needle file, this is the wrong included angle, and please be sure to have some protection on the Swiss needle file handle. I saw one lad at school with the handle of the file under the skin of his right palm like a large thorn.

Then clean this thread as above. A trial assembly without any oil should see the thread screw in further than before. If this happens replace the feedscrew and then lightly oil the thread which should go fully home now. If you have to use the Tommy bar it needs more work I am afraid.

My feeling is that when you unscrewed the thread it actually "picked up", not your fault these things are sent to test us. As you say you had to use the Tommy bar to release the housing. Once the housing had been released it should have unscrewed by hand, the grease nipple providing all the leverage needed.

Regards

Gray,

Edited By Graham Meek on 07/05/2020 10:30:09

Just by coincidence Neil has an article waiting a publication slot on this 36 mm diameter Boring & Facing head. The above boring head was made for a friend who has a Mannix MM 250S3 Milling machine, the taper is a BT 20, hence the 20 mm cutter.

The feed of this concentric dial Boring Head to the feedscrew is by a single start worm and gearing to a conventional feedscrew. To keep the worm profile simple the Pressure Angle was chosen at 30 degrees. Thus the 10 tooth input gear has an Involute form with 30 degree PA. The feed works in two directions to meet the requirements of the two boring tool positions. There is a neutral provision in the gearing for manually setting the boring tool, so the operator does not have to wind the dial for this purpose. The dial can be set to zero, one full turn of the dial removes 0.1 mm from the bore, and two stops can be set to limit the travel when spotfacing. The feed is 0.05 mm per rev. A built in clutch in the feed ring allows the feed to stop once the limit stops are made.

With regards to forming the flanks of the single tooth cutters that I use. A series of photographs recently appeared in the thread on my design for the Myford Tailstock dial. Or you can find them in my album.

As regards the flank radius this is always going to be a compromise. B&S cutters cover a range of teeth per cutter. For obvious reasons the cutter will have to be made to cut the smallest number of gear teeth in that particular range. Thus those at the top of that gear cutters range are going to be a compromise.

I design my cutters to suit each gear used, that way the teeth are as close to a hobbed profile as I can get with a form cutter. These gears run extremely smoothly together because of this. While I draw and work exclusively in Metric very often an Imperial cutter is so close that it is not worth worrying about, so I use that.

I am currently working on the 66 mm diameter bodied version of this B&F Head following numerous requests for a larger version of the 36 mm baby of the family. (I built the 50 mm version some time back, see below).

Regards

Gray,

Edited By Graham Meek on 02/05/2020 11:40:19

You could make your own for free and have the money for other things!

Regards

Gray,

Although Ian seems to have sorted his problem, it might be worth making a note that DIN 5480-1 lists splines/serrations with 19 teeth. The number of teeth depending on the base diameter of the spline and the size of the Module, (Mod) being used. Straight or Rack profile as well as Involute splines are listed under this specification, but it relates only to 30 degree Pressure Angle(PA).

ISO 4156 Covers 37.5 and 45 degree PA.

Regards

Gray,