Member postings for Graham Meek

Hi Neil,

Thanks for the kind words, MEW came to the rescue there and saved me a lot of time having to re-invent the wheel.

I have been pondering today whether to add the self indexing mechanism to my Compact 5 version of the turret, it will fit in a reduced size and it would be nice to have continuity.

Regards

Gray,

Hi John,

Thanks for the kind words, the toolholders eliminate the need for packing due to the sloping tool slot. The close fit in the toolpost means swarf is not a problem each time the toolholder is changed. Plus they are cheap and dead easy to make.

Regards

Gray,

The use of a one way clutch was to permit both the Turret, or the topslide, to be set at any angle.

If a ratchet based self indexing system had been used then this would have compromised being able to set the topslide at any angle. Only those angles that were within the ratchet geometry would have been possible. This was a situation which I considered intolerable as it seriously reduces the flexibility of the original design.

Regards

Gray,

With the original Tool Turrets which George had in mind on the Herbert Combination Turret lathes. There was no topslide on these lathes to worry about. Thus these tool posts only ever had to index every 90 degrees. The inner workings of these turrets that I have seen, is truly a work of mechanical art.

The sequence of events for those interested goes something like this.

As the locking lever is being undone one paw engages a ratchet, with a cam that retracts the indexing pin mechanism down into the base. This base supports the turret on a central pillar, and attaches it to the cross-slide. Shortly after another paw engages another ratchet which moves the turret to the next indexing position as the lever is unlocked further. When the turret is over its next location the indexing mechanism is now free to engage and the turret snaps into position. The locking handle is returned for the process to be repeated, or to be tightened. The number of parts and the complexity is mind boggling, no one would ever consider this from the outside. Yet these turrets worked faultlessly for many thousands of operations, maybe millions?

Regards

Gray,

Many of the tools I have built in my career as a Toolmaker have been fitted with "spring loaded urges" to bias the component being machined or assembled in a specific direction. WDS tooling aids call them "Spring Loaded Stops", but it is not what I have known them as and in this instance it is not what they are.

Urge might not be the exact word to use in this context, grammar was never my strong point, but it is what is happening to the index pin of the turret. The vertical spring loaded pins, due to the large radius on the end faces are forced down the angular face of the ratchet. This induces an anticlockwise moment on the turret which "urges" or "forces" the indexing pin towards the ratchet face.

Under normal circumstances with GHT's original design the torque applied by the locking lever, combined with friction contact between the various components provides the anticlockwise moment. Depending on the enthusiasm used to tighten the lever, (the human element), then there will undoubtedly be a variation, due to the varying moments of inertia involved with each tightening sequence.

Regards

Gray,

When the turret locking lever is undone the one-way clutch instantly comes into play and moves the turret as the lever, or in GHT's case the ball handle continues to be undone. Going slightly past 90 degrees of movement allows the index pin to drop. As the lever rotation is reversed the clutch dis-engages and the spring loaded urges bias the index pin towards the ratchet face. Further movement of the lever merely locks the turret.

The biasing of the index pin towards the ratchet face has totally removed any very slight variation I was getting in repeatability prior to this modification, (George talks about "tenths of a thou" with his own turret). As there is now a constant force being applied to the indexing pin and no chance of the pin moving away from this face even slightly.

Regards

Gray,

Those members who have followed my work over the years know I favour the 4 Tool Turret. While I know this is not everyone's cup of tea it does have its place in machine tool history.

A recent problem with my adaptation of George Thomas's Turret design was the tendency for the turret to stick firmly on the cone. Rather than just flick the turret round with the index finger of my left hand. I had to grasp the turret with my hand to free it.

Cutting oil was migrating along the bottom face of the turret and then up the cone taper. That plus a "close fitting" cone which has got better over the years required a solution.

George said in his article originally that he would have liked to make the turret self indexing, similar to the "Herbert Combination Turret lathes at the works". As my thought began to work out what to do as regards the sticking of my turret my mind went back to the above statement.

Two spring loaded urges pressing on the ratchet face would take care of the sticking problem. If these urges were so placed they could be used to re-index the turret as it moved around the central post. The angular faces sliding down the ratchet faces so urging the turret towards the indexing pin with a constant force.

The only problem now was to move the turret as the locking lever was operated. This came in the form of a one-way clutch, which came direct from the pages of MEW.

A clutch is preferable to a ratchet system, especially when the turret is being swung through an odd angle. Such as it would be when screw cutting for instance. Always assuming the reader uses this method of screwcutting, not everybody does. It allows for the turret to be set at any position and not dependent on any ratchet position.

Below is my original design adaptation for comparison.

The only external difference is the additional flanged plate held on by two M4 capscrews. This also stops small particles of swarf migrating into the needle roller race that I use in my adaptation.

I have been using this set-up now for a few months and it has come up to my expectations. All the parts are mild steel, with exception of the curved spring loaded cams and the rollers in the clutch which are silver steel. If wear does become a problem then I shall think again about my material choice, but for the time being I am prepared to run with this.

I have schemed out an adaptation that could be fitted to George's original design. If there is enough interest shown, I am prepared to write this design up and incorporate the modification to GHT's original.

Regards

Gray,

Hand reamers are like all cutting tools made to very close tolerances, of the order "+0.00* to +0.00* mm" to suit different hole standards. I have yet to buy a new reamer that is not on top limit. Usually H8 hand reamers are stocked, but special order can get you H7. With machine reamers usually stocked and produced to H7 tolerances, or again to any "hole fit" that is required, to special order.

A machine reamer usually cuts oversize when too much material is left in the bore, it will also wear quickly. Leaving too little material can also cause problems, usually giving a poor finish.

Another cause of hole size problems is by how slowly the reamer is passed through a bore. The process wants to be done quite swiftly, but at the same time the reamer must be allowed to cut. The correct lubrication is another area that will influence the size and the finish.

For a 3 mm reamer I usually use a 2.9 mm drill, for a 5 mm hole I use a 4.85 mm drill and for an 8 mm hole a 7.8 mm drill. In all cases I drill 0.5 mm smaller first before I use my pre-reaming drill. As can be seen the amount of material left in the hole for reaming is getting bigger with the increase in the size of the hole.

There is however a limit to how much that is left in prior to reaming and there are many PDF's by the people like Taylor+Jones who give guidance on this topic. The type of material being reamed is also of great importance. I would never expect a reamer that has been used on steel to produce a very good hole in brass or bronze. If a lot of reaming in the last two materials is envisaged it would pay to keep reamers specifically for these. I also never cut these materials dry with a reamer, despite what the text books might say.

I hope these notes help those who have struggled in the past.

Regards

Gray,

Hi Phil,

Hope you are well. and glad to hear my tooling is still working well.

The reason I changed to GHT's Turret was based on problems I was having keeping my own Interchangeable Tooling free of very small bits of Brass swarf. These bits of swarf were making it impossible to hold some very tight tolerances on a commission I had undertook.

I had always though my original design was easy to keep clean, up until this point. With only 4 faces to keep clean. The prospect of another larger batch commission meant something had to give. I had always promised George I would give his turret a go one day. One thing that had put me off before hand was packing. However I think I have managed to work out a system that does not need packing.

By the way the larger batch was done much quicker than the original smaller batch. The Turret got left on the machine and my interchangeable system was sold.

I have added recently a refinement to the original design in that the Turret is now self indexing, but as yet I have no photographs of this. Those who have seen it think it warrants an article, but we shall have to see on that.

Note how there is no chance of swarf to get into the location slots.

What is not shown in the above photograph is the register pins beneath the tool holders. One such pin can be seen in the top of the second standard tool holder. I now have dedicated insert tool holders again with registration pins. Thus I have the advantages of both systems.

Regards

Gray,

This is a solution I made in the late 1980's before going back to a 4 Tool Turret, based on George Thomas's design.

Regards

Gray,

Hi Chris,

Not wanting you to go to a lot of work only to find the project might not live up to your expectations.

You might want to give your location stop arrangement some thought. As I see it, the toolholder has to come out either, forwards. Okay if the work is in the chuck, and the carriage can be moved to the left. Not so convenient if the work is between centres.

Or, to the side, by undoing the clamping lever several turns to allow the toolholder to come out that way. Okay getting the toolholder out, but not so easy getting the holder back in as the plate needs to be lifted whilst doing this.

Fitting a spring under the plate might seem at first glance a solution to holding the plate aloft for re-insertion from the side. However if the angled faces are the same length/height then when the plate clears the toolholder angled face it will also clear the tool post face. The plate is then free to follow the lever due to the friction between the lever and the plate. Thereby loosing its alignment with the toolpost.

As a suggestion, a dowel pin in the plate, which fits loosely in a hole in the toolpost will maintain alignment under such circumstances.

Regards

Gray,

Edited By Graham Meek on 04/09/2019 16:19:22

Jigsaw blades come on a variety of materials and could make a fairly cheap source of material for such a system, but it would probably mean some form of clamp to hold the blade, rather than a hole.

Regards

Gray,

Thanks Michael,

A good few ideas on that site, and several useful tools too. There are two items I have been meaning to add to my toolbox for some time, so you have saved me time at the drawing board.

Regards

Gray,

Hi John,

Thanks for the compliments, the Emco Dividing Head, come Rotary Table, is a handy piece of equipment to have and it does get a lot of use in my workshop.

Regards

Gray,

Hi Joe,

Until recently the slope or fall on the surface of the lane was towards the property boundaries on my side of the lane. The result of this is flooding to the rear of the properties. The repairs to the surface by sub-contractors over the years have added to this. The district council view is that water will flow up hill in this part of the Universe and into the french drain they installed but have no record of.

It does not help that outside my boundary is the lowest point in the length of the lane, that is both ends are higher.

For the past year I have been struggling to get anything done, however last month the County council installed the drain you see below and graded the lane towards it, but only in front of my boundary.

The result was my gate just clipped the far corner where the ground is higher. Why not just take this bit off? Well this is a public footpath, and to tamper with this surface carries a hefty fine. Not to mention a liability for anyone who should get hurt from said tampering.

Hence my solution, I doubt the council will be doing anymore repairs in front of my gates, this has been a costly lesson for them.

Regards

Gray,

Edited By Graham Meek on 30/07/2019 10:39:05

This morning I made the final piece of the jigsaw, note the grease nipple for future lubrication, if I can bend down to get to it?

Then began the fitting of the completed parts to the gate.

Well I hope you have enjoyed my bit of Garden Engineering, there is still things to do to finish the job off. Like putting some concrete beneath the aluminium base plate and extending the hinge pins. The latter is under way but I am waiting for the loan of a right angle drill to do this operation.

Regards

Gray,

Yesterday was a good day, despite the 33.5 C workshop temperature. The mounting plate for the Cam is now complete.

The profile of the plate was an old jig base salvaged during my Toolmaking days, this includes the four counterbored holes in each corner. The various mounting holes and rotary table location holes were done earlier in the morning as was the rectangular pocket,

The extension handle for the rotary table is one I made years ago, it saves having to fumble around under a component for the table handle,

The last operation was to drill and tap an M8 stud hole, to clamp the mounting plate to the post.

Note how the job is dropped over the back edge of the table to gain room under the spindle nose and the workhead is slewed around to get to the job. There is not enough travel on the Y-Axis to allow the workhead to stay in its normal position.

Regards

Gray,

Hi Joe,

The largest gate which I am working on is 3 m long and 1.8 m high. Made from 50 mm heavy gauge box section and clad with 25 150 x 25 mm boards 1.8 m long. A conservative estimate is 0.25 Ton, but I reckon it is more than this, probably 0.4.

The other two gates which are in front of the garage, are 2 m x 1.8 m and of similar construction. These fold on one another like a bi-fold door. In total my gates cover 7 m and the uprights that hold the gates have a strut brace at the top to keep the posts apart. This strut can just be seen in the photograph.

I am like IKB, I don't like to have to revisit jobs once I have done them, so there is definitely some overbuild in these gates. They have been there for nearly 40 years and other than paint the steel and treat the wood no other work has been needed. Of course I have no control over the repairs to the footpath which has prompted my current project.

Regards

Gray,

Hi Joe,

I drilled a 6.5 mm diameter hole at every 5 degrees moving on the X axis at each location. This was the largest drill due to the centre to centre distance. You can see the plot position list, (not very clearly) under the spanner.

This process was followed using a 14 mm slot drill, fed down manually using my fine feed on the quill. Finally the form was cut using a 20 mm slot drill, this cut was done using the powered down feed. I then set the rotary table over to correspond to a 2.5 degree increment and went through the same process with the powered down feed to take off the bits in between the previous cut. The last operations took just under an hour. The manual dressing to take off the peaks took about half an hour.

Regards

Gray,

I thought I would share another project with the forum. This involves garden engineering. The rear gates to my property are substantial things and originally the largest gate would open fully and run parallel with my boundary. Due to the lane surface now being higher than it used to be the gate will only open 120 degrees.

While I could have had the hinges for the gates cut off and welded back on higher up, raising the gates this would allow cats and small dogs to come under the gate. Thereby creating another project to stop this.

In the end I have decided that if the large gate could rise as it is being opened by about 40 mm then this would make things easier as only one gate needs modifying.

Thus the FB 2 was pressed into service this week making the cam to raise the gate.

The piece of thick wall pipe is 140 mm diameter and 13.5 mm thick. The picture taken this morning was yesterday afternoons work. Hand finishing this morning finished this part of the build.

I will post the next piece of the jigsaw when I have made it.

Regards

Gray,

For those wishing to make the tractor as it is drawn I have produced a drawing of the gear tooth cutter for the 19 and 57 tooth gears. Based on the information given on the drawing.

Regards

Gray,