Member postings for Graham Meek

Hi John,

I have sent you a PM

Regards

Gray,

Hi John,

The gear I looked at quickly yesterday morning which for 1 Mod is wrong is Pinion 4-24. Today I see the note "same profile as 3-18", (there is a lot of info on these drawings). These two gears are made using the profile shown in the small drawing on Gear 3-18. From the details given I do not think these gears are of an Involute form. I think they are intended to be a Cycloidal form, the same as the Clock Makers use. Making such cutters to use in a flycutter is simple. Using 1.25 MOD will not give the tooth thickness specified, ie 2.5 mm. From what I have worked out the tooth thickness will be 0.25 mm smaller, but still larger than gap cut by the 1.25 MOD cutter, which is 1.9635 mm.

The gears can be cut using 16 DP as the base but with 16 teeth on the pinion and 48 teeth on the gear. O/D of the pinion will be 28.57 and the gear 79.37 mm, not that far away from what is drawn.

Regards

Gray,

Looking at the PDF I have, the gears are 1 MOD. However I have noticed one gear has the wrong outside diameter.

Regards

Gray,

Although the picture is not very clear the cutter looks more like a Woodruff cutter than a Tee Slot cutter. Tee slot cutters in this range usually come with staggered teeth and with a lit more of a "Gullet" to help clear the chips.

I would not be running a Tee slot cutter of this size above 300 rpm and there is a real need to clear the chips. Flushing with coolant or an continuous air blast is a must.

Regards

Gray,

For those Forum members waiting for further details about the article. I managed the finishing touches this morning and it is wending its way to Neil's desk as I write this.

Regards

Gray,

Edited By Graham Meek on 08/07/2019 16:09:37

Hi Adrian,

The column on the FB 2 is counterbored at each end to take the 60 degree cones to allow the machining of the outside diameter. The counterbore at the top end also has a floating plate retained by a circlip, to attach the feedscrew bracket. The stud idea uses these counterbores to both seal the column and take the stud plates. Nothing would protrude beyond the column ends.

Also on my mill I have made new Gib strips that almost within 0.03-0.05 mm fill the space available for them. Too many of the machines today have loads of space for the Gib strips to move around in. I am beginning to wonder if that is the root cause with your machine. Pushing with my feeble frame on the head of my FB2 I can only deflect a clock 0.02 mm with everything locked. You can see the one on the X-axis in the photo's above.

Regards

Gray,

Hi Dave,

Although the cast iron is reasonably thick, it needs to be given the duty it is being asked to do. While it is a good bearing material for machine tools and lovely in compression. In tension and torsion it is not so good, hence the thickness.

Another problem with cast iron is the nature of the material can change through the casting. Far better results would have been had if the part had been a spun cast tube.

This is one of the reasons I suggested a stud down the centre under tension. It would give additional strength to a cast iron tube by holding it in compression and thus balance out any bending moments due to machining and drilling. Plus any bending moment due to the weight of the overhanging milling head. It would also improve the torsional resistance.

By stud I am not thinking a piece of Screwfix 12 mm, what I had in mind was 25 mm diameter EN24T. It cannot be larger than this as it will not pass up the mandrel of my lathe. Some fine threads on the end would allow a reasonable torque to be applied, (yet to be worked out).

Adding this stud should also tune out some of the natural frequency mentioned above. One other thought that crossed my mind while thinking about this mod on the steel tube of the Emco, was to fill the void with oil under pressure. The pressure of the oil could be altered to increase the tension on the stud or lowered to reduce it. I would not advocate trying this on a cast iron tube.

Regards

Gray,

I think the devil is in the detail. I know the Emco FB 2 uses a high specification material for the column. If the "clones" have not followed with this material then there is going to be differences.

Some of the round column belt driven mills I know have cast iron, or cast steel columns. This would be considerably cheaper to produce than something like the Emco column.

Round columns for machine tools have been used for some time, I remember working on Jig Borer, an Oerlikon KC4, which had two round columns.

As regards the filling of the column with any medium I am not convinced. The column is experiencing more twist when milling, with some bending, but when drilling it would be just pure bending. Twist and bending are not good for concrete, plus a lot of concrete columns are seldom solid, they too are reinforced hollow tubes.

Regards

Gray,

Hi Dave,

The theory is good but unfortunately I think you will find the concrete shrinks on setting. You then end up with a concrete block floating around in the column.

I have considered putting a long stud up the centre and applying a pre-tension to the column, this should alter the natural vibration point of the column. However if it was over done it might distort the column.

Regards

Gray

Hi Adrian,

Yes the first picture is a quill lock. What a lot of Emco owners do not realise is that there is a Tufnol gear in the input train from the motor to the gearbox. These have been broken in the past where owners use bottom gear to lock the quill.

This little unit ensures there is no strain through the gearbox.

My column is 78 mm diameter. One of the posts above mentioned checking the condition of the slides on the table. I once had a problem with the finish on the end of any bar when cleaning up the face with the side of an end mill or slot drill. Of course initial thoughts turn to play in the spindle, but as this was ruled out I looked at the slides. Sure enough both were a little on the loose side.

Tightening the slides made a world of difference, but, and it is a big BUT do not over do the tightening. To adjust any slide way you need to take off the feedscrew and push the slide by hand. If it is that tight, that you cannot then this will cause premature wear. The only correct way to adjust the head to column slide is with the head off and feedscrew removed. The Gib strip on the guide key wants to be loose so that you can set the adjustable clamping bolts to get the slideway sorted, once these are set then adjust the Gib.

Get this wrong and you can get to a stage where the slide will stick, then suddenly drop to take up the play in the feedscrew.

Regards

Gray,

Hi Dave,

The Over arm support is used mainly for gear cutting, the additional support improves the finish.

I have also added an bracing system when using very large DP or Module cutters.

Lastly the Y-Axis stops are another of my designs,and are not fitted to the machine as standard.

Regards

Gray,

Here are a few more additions I have made for the FB 2,

Regards

Gray,

Hello Joe,

Nice set-up, OH for a bigger workshop.

The Red and Grey machines were the last of the line. I think the decibel levels of the machines were getting close to the then latest regulations. Emco then went over to belt drive, one of the two machines available I think used a similar FB-2 head casting, this had variable feed. These came on a different base casting which I think was from the Orient.

Regards

Gray,

Irrespective of the type of Slide way, the "Column" on any bench mounted machine is a torque tube.

I have used Emco FB 2's for for nearly 40 years now and if treated with respect they can turn in a surprisingly good performance. I would not change my machine for anything else.

Correct adjustment of the slider on the column is the secret.

As regards Fine feeds, here is something I added some years ago .

The attachment was recently described in HSM.

Regards

Gray

Hi Adrian,

I may have misled you slightly. Only extend the quill sufficiently to do the slot in hand.

Regards

Gray,

Hi Adrian,

I see the mill in your photo album is a clone "type" of the Emco FB 2. As the Emco mill has a strip attached to the column to ensure alignment, I am presuming yours is the same.

To produce a slot I usually drill a hole 0.5 mm smaller at each end of the slot if it is not open ended. Then with the cutter inserted I lower the quill, and lock it. Then set the depth stop on the quill. The whole head is then lowered and the cutter brought into contact with the job. The down feed is then set to zero. Retract the quill and put a cut on using the down feed handwheel.

Lock the head to the column. Start the machine and at the one end of the slot feed the cutter down using the quill until it hits the stop. Machine the slot to the other end, (I usually set stops when doing slots), traverse back to the start. Repeat the above until the slot is to depth.

To get a really good slot use an undersize cutter first, and rough out the slot. Move off the centreline an equal amount to remove some, but not all of the material on the sides. The difference in the undersize cutter and the size of the slot minus 0.2 mm is my usual.

Move back onto the centreline and insert the correct size cutter. Again I set the quill stop as above. Then at each end plunge to depth. On the last plunge cut lock the quill and traverse to the other end of the slot and back.

It takes longer to write down than do, I hope this helps?

Regards

Gray,

Hi John,

I have agreed with Neil to submit this as an article for publication in MEW. I hope to finish the text and update the drawings by the end of this month or early next month.

Regards

Gray,

Hi Thor,

Thanks for the kind words about my work. I must admit this design has fought me every step of the way. Even fitting the extension piece this morning required an additional modification. In the form of a scallop in the rear face of the extension piece to clear the aluminium casting that carries the quadrant banjo.

Whilst it has been a challenge I have enjoyed every minute of it, back to the Steam Wagon now.

Regards

Gray,

This week has seen all the required parts made and fitted. The Stops may come in for a slight design change before I put pen to paper.

What cannot be seen in the above photographs is the keyway running on the underside of the Trip Rod to orientate the Stop. There is nothing worse than trying to set a stop which has a mind of its own due to the eccentric nature of the design.

The clutch was pressed into service to make a new M8 stud for the extension piece. This is required to allow the same range of adjustment as Emco originally intended.

The parts in-situ,

This is the original position of the stud before the extension was fitted.

And after,

I hope you have liked my project on the Emco?

Regards

Gray,

I forgot to add one photograph the other day showing the Dog Clutch shape.

Over the weekend I have had a chance to fit the unit to the lathe. The Trip Rod and Trips are still to me made hopefully this week will see this project finished.

The unit is very quiet in operation, which did come as a surprise. I thought at the design stage that by enclosing the extra gear train in its own gearbox this might quieten things down but I was pleasantly surprised by how much. The noise is not dis-similar to that made by the Hardinge, even down to the clunk as the dog clutch engages.

The lower bearing was I thought going to give me a lot of trouble as regards alignment. The main bearing block sits on an unmachined portion of the bed casting. The bearing block is held in place by the headstock end hold down bolt. To overcome the roughness of the cast surface I used a 1.5 mm thick Aluminium spacer, which seems to have done the trick.

Hopefully later this week I can post the remaining parts.

Regards

Gray,