Member postings for Graham Meek

Thank you both for being so understanding. It may be a while before it gets into print though.

Regards

Gray,

Hi Jamie,

The Compact 5 Mill was my first choice when replacing the FB2, but as you know these are like Hen's Teeth.

You are right in your assumption about the cross pin driving the feed screw. Holding the feedscrew in a collet and reaming a hole was the easiest option. Using a Woodruff cutter it is a simple matter to put in the slot, which does not need to be a good fit on the drive pin. I used a 3mm pin with an 1/8" or 3.2mm wide slot. This avoids any slot symmetry problems.

Hi Steve,

I am hoping in due course to write an article on the feed unit. Maybe I can get John to do a 3D of the design in the meanwhile.

Hi Bernard,

As with my answer to Steve, it is my intention to write up this modification later on and if Neil is agreeable I submit the article.

Generally,

As regards Stepper motors this is a bit too complicated for me, and I do recall on some machines fitted with stepper motors I have used, that Cogging is an issue especially when trying to make small adjustments.

My method is dead simple, this gives me no such problems and the only cost is the 12v 60 RPM gearbox motor, the power supply I already had.

Regards

Gray,

Edited By Graham Meek on 25/07/2022 19:33:10

Well the FB2 and the Maximat Super 11 have now gone and the Screwcutting Clutch for the Compact 5 is now up and running. Along with a dedicated Retracting Topslide.

Work has now transferred to getting the Proxxon Mill to where I would like it to be.

The work on the Powered table feed is now complete as shown above. This has been used by jury rigging the wiring to produce the Delrin Connector block, come Micro-switch housing, as well as the End Cap for the motor. The finish produced by this small machine has impressed me.

Please ignore my makeshift base for the milling machine. Work is in hand to make a base similar to my Unimat 3 base in the background.

The Switch nearest the milling table engages the drive via a Dog Clutch. The Dog Clutch slides directly on the "D" shaped drive spindle on the reduction motor. As well as the drive shaft for the table feedscrew. Making the D-shaped hole was simplified thanks to an idea given to me by John Slater. More on that at a later date hopefully.

The second switch controls the direction of travel via a pair of micro-switches. Power currently comes form my Proxxon Micro-Mot power supply. This has a variable output and gives quite a good range of feeds with the 60 RPM motor. I may at a later date make a dedicated 12v power supply and control this via a PWM.

The Feed Unit was designed originally for John's X1 milling machine, another of our joint ventures. Thus it would be possible to adapt this design to fit most of the smaller milling machines. It would only require a different Endplate

One possibility I am mulling over at the moment is a variable power feed for the Compact 5 Leadscrew using largely the same design.

Regards

Gray,

Thanks Nigel,

Alas Emco have moved on from the Hobby machines, having amalgamated with a much larger concern. They are more industrially based these days. This to me is a pity as they gave the Hobby many innovations over the years, which have been copied around the world.

I have been using the U3 today to put the finishing touches to my Proxxon Milling machine table feed attachment.

Regards

Gray,

Hi Keith,

I am sending you an email about the parts I used.

Regards

Gray,

Edited By Graham Meek on 20/07/2022 10:49:31

Just tell them "You are scammers, you know it and so do I". There is usually a prompt Brrrrrrrrrrrrrrr.

What ever you do don't admit to it being you speaking, or answer "Yes".

They usually pronounce my name so badly that I say, "no one of that name lives here". This has the advantage that it usually stops all further calls.

Regards

Gray,

Multi-flute countersinks are a problem on smaller machines. The problem is the backing off behind the cutting edge is too great. Allowing the edge to rub on the work. Putting a piece of Emery Cloth on the countersink is increasing the contact area behind the cutting edge. However I have found that this does tend to blunt the tools quicker.

I use a single cutting edge countersink made by Magfor, these seldom give trouble. RPM is usually the root cause of chatter with this type of countersink.

Regards

Gray,

"Typo error"

Edited By Graham Meek on 11/07/2022 12:03:18

New switches are available, at a reasonable cost. The design has not changed much over the years.

Regards

Gray,

The Multifix tooling on the Hardinge I worked during the 70's came with a parting blade which had more of a "V" shape ground in the top face for the length of the blade, so these types of tools have been around for sometime. I have been trying to remember the make of the blade but with no success. I do remember it was only about 11 mm high.

GHT did try a parting tool ground like this as well as one ground with a shallow inverted "V" on the Front Rake. The latter is something I have tried, but found a straight face to be just as good when using a dovetail shaped blade. The end goal is trying to get the width of the swarf narrower than the cut width. The inverted "V" might seem the wrong way to go, as the cutting edge is longer than the width of the tool, but the secret is in the fact that the bottom of the "V" hits the work first before the outer edges. This forces the centre of the swarf to rise up from the tool and thereby reduce its width.

The problem with power feeding is the change in the peripheral speed as the tool nears the centre, with a constant feed rate. On the Hardinge this is easy to overcome as it has a variable feed. On larger lathes like the DSG, VDF and Colchester this does no seem to matter so much, as on these machines you do have the facility to change feeds on the move as it were.

Regards

Gray,

Hi Tony,

I hope all is well with you?

Not so good this end, more importantly as of the this morning Jean's health, and in recent months mine, are both taking a nose dive.

Regards

Gray,

Generally,

My observations on parting tools might not suit everyone's view point, but they have worked for me and have never given me any breakages or jams.

The Top edge of the parting tool blade is left with the ground dovetail face, and it is parallel to the plane of the bed surface. The angle of the dovetail face has two functions in the cutting action. The most important is, as the edge is sloping it turns the chip immediately it leaves the cutting edge and puts the chip on its side. Thus the swarf is narrower than the cut and cannot jam up.

The second advantage is that even with the parting blade ground square to the lathe centre-line it still has a pip-less parting action. As the tool is in effect producing a very shallow cone. As the cutting edge is really a product of the dovetail angle and the ground square edge.

A lot of people grind the top face flat, or with a slight top rake. This not only looses the above advantages but it also is reducing the width of the blade due to its in-built tapered section. It also restricts how deep the blade can penetrate the work. As the unground blade above the new ground top face is now wider than the cutting edge. It might not be much, but it is enough to give you a bad day.

The Front rake angle if it is too sharp, allows the blade to penetrate the work very easily. This in my view is what causes the dig-in, as there is no, or very little resistance felt on the feed handle. This results in too big a cut and a jam, dig-in, or breakage. If a moment is taken to think about it. A true vertical face would not cut, and by not cutting it cannot dig in. As the Front rake is increased the tool is allowed to penetrate the work, depending on how much this increase is, equates to how easily the tool can be fed into the work. Hence my opening sentence here. Some resistance to the cutting tool is a good thing in my book.

As I said these are my rationale, it is based on my experience, and advice given to those apprentices in my charge . Even on the smaller Compact 5 I use now, I still have the same set-up, and have been recently parting off 16 mm bar, (BMS & Silver Steel) at 330 RPM with no problem.

Regards

Gray,

The front rake angle is the killer as regards a problem with digging in.

This is the blade holder I made for my Emco Maximat Super 11 lathe. This was the second blade used in 40+ years. The blade is 13 x 2 mm section, it has a dovetail section and is only ground on the front at 10 degrees.

The section of the blade means the swarf is turned on its side as it leaves the cut and it never caused a jam. I now use an 8 x 1,5 mm on my Emco compact 5, with the same style holder. Parting off is carried out with the carriage locked and at normal turning speeds.

I hope these notes help,

Regards

Gray,

Nice to see white writing on a black background.

Red and Green writing over a photograph is not seen by me, and it plays havoc with my eyes, not to mention the Migraine this combination induces.

Regards

Gray,

Hi Jon,

For what it is worth it happens to the best of us.

When I recently completed the Screwcutting Clutch for the Emco Compact 5 and switched it on for the first time. I was filled with blind panic. Moving the operating lever to the left sent the carriage to the right. That's not right I thought, what have I done wrong.

Switching the lathe back on it worked perfectly, then the light came on, Holmer Simpson comes to mind, DOH.

My only advice is not to worry about a single incident, be more concerned about repeated events.

Regards

Gray,

It only requires one more gear stud in the gear train to do a Left Hand thread.

Given the simplicity of the C8 Banjo quadrant, it would not be that difficult to make a new longer one, should it not be possible to get an extra gear stud on the original banjo. It does not have to be made of steel, aluminium would do.

If a new longer banjo should foul any of the drive pulleys / belts. Then the banjo can be set vertically in front of the mandrel.

Regards

Gray.

The Leadscrew is indeed Trapezoidal, by that definition it is 30 degrees included angle. This being the Continental standard. A 29 degree included angle means it is an Acme Thread.

Any Bronze is better than no Bronze at all. If I were making one and given the limited use this Axis gets compared with the X&Y Axis, then I would opt for Colphos 90, as this is much easier to machine. At a push I would substitute Aluminium, especially if you have not cut a Left Hand Trapezoidal thread before.

Just be aware that there will be wear in the centre of the Leadscrew, there always is.

Regards

Gray,

Thanks Jason, I can see them OK,

Regards

Gray,

Darren / Jason,

I noticed in my Compact 5 post today there are images not present. Clicking on them it says they cannot be found or have been removed. Although the originals are still in my albums. Did this occur because of the change over? OR Is there another reason?

Regards

Gray,

Now I have the workshop almost straight I have taken a breather and done some more machining.

These are all the parts laid out ready for assembly. Below is the finished attachment fitted to the lathe.

This is the fully forward position, note the position of the topslide end with regards to the aluminium topslide base.

This view shows the slide fully retracted, the distance moved is 4 mm. Due to the longer feedscrew bearing the topslide has a much smoother action now.

I am hoping when I post the next photographs it will show the slide in use. It will be cutting a 10 TPI worm gear. This will be part of an attachment to bolt directly to the C5 Dividing attachment which will give this attachment a conventional 40:1 Dividing facility. This however is a way off as yet as I have the table feed for the Proxxon mill to finish first.

Regards

Gray

Derek,

I have in other posts on this forum outlined the way to go about the Slider adjustment. This cannot be done with the head in-situ. The Column assembly needs to come off the machine, the feedscrew removed and the column held while the slider is dealt with. The Gib adjusting screws need to be backed off, (19) this allows the fit between the slider and the column to be adjusted. It should move freely, without any side play from one end of the column to the other, but beware the keyway will foul towards the bottom of the travel.

The movement should be able to be carried out with hand pressure alone, any tighter and it is too tight. Then it is possible to adjust the Gig strip, and again after adjustment this should move with hand pressure alone.

With the slider at the top of the column and locked put the feedscrew back in and lock up the bolts, but not too tight as the area beneath the housing is not fully supported. I have known some users break this part.

Re-install the column and refit the head. (The head can be rested on the milling table to remove it with suitable packing).

I hope this helps,

Regards

Gray,

I made Phos Bronze main feedscrew nuts many years ago for the FB2, after the initial adjustment they were never touched. Despite the Hobby build of the FB2 it does handle work far outside its scope.

Somewhere in the back of my mind I think Emco specify 0.05mm backlash as the desired goal. It may have been on my Emco F3 that I read this. It does go to show there needs to be some backlash, or premature wear takes place as there is no room for the lubricant.

Regards

Gray,