Member postings for Graham Meek

A few casual observations.

I was always told good engineers can't spell, by my Tutors.

Plus, something my Grandson said, "When are they going to fix the English Language, it is broken". In his world each word should only have one meaning. I do have to agree with his comment about it being broken. English Grammar was certainly a foreign language to me in my school days.

The old "i" before "e", except after "c" rule, falls down with with the word "Foreign". They clearly forgot to include that dreaded "r" again.

Regards

Gray,

I use sections of Ground Flat Stock, or Gauge Plate which I have either surface ground myself or had a local engineering firm grind for me. GFS is seldom dead on size, usually plus and on the thinner sections the edges tend not to be square with the width of the section. Hence why I have them ground.

Parallels to suit my particular needs are thus quite easy to make. The latest requirement with the Proxxon mill was for 50 mm long parallels. Not many firms are making this size. The parallels I made for my Emco FB2 were made 30+ years ago and show no signs of wear.

Regards

Gray,

I have had several PM's over recent months for details on the above modification. I have written up some notes for anyone else who is considering this salvage scheme.

"This repair is not an easy task and it needs to be approached methodically. The only safe surfaces to come off are the cross-slide flat ways. As the Lug portion the leadscrew passes through is tapered on all four sides.

Using parallels the cross-slide faces are bolted to a small angle plate. By using a couple of dowels about 5 mm diameter in the dovetail vee the carriage assembly is clocked parallel to the edge of the angle plate. The dovetail ways of the cross-slide now being vertical to the surface plate and the bottom "working face" of the angle plate. (Lug needs to be uppermost)

In a vertical type mill bolt the angle plate to the machine table. With a close fitting "turned spigot" in the existing leadscrew tapped hole and using an edge finder locate the leadscrew centre-line, parallel to the angle-plate vertical face. Once on this centre-line and using a Verdict type clock. Clock either side of the casting Lug to bring the leadscrew lug central under the machine spindle.

From memory the thickness of the casting at this point is 15 mm. A 10 mm drilled, bored and reamed hole is then machined in the casting.

Re-clamping the angle-plate such that the leadscrew centre-line is now running vertically. Using the turned spigot again, clock to get the leadscrew and spindle centre-lines concentric. Open up the existing tapped hole using an 8 mm end mill, followed by an 8.1 or 8.2 mm drill. Nothing bigger as there is not much meat about here.

It is best to rough out the PB nut, tap the 8 mm LH thread and then finish machine the outside diameter to size, (9.99 mm for a reamed hole). Tapping PB throws up awful burrs and distortion on the diameter, hence why I used this method. It goes without saying that the tapped hole has to be on the centre-line of the 10 mm diameter, so some careful machining is required on this part"

I hope these notes help.

Regards

Gray.

Edited By Graham Meek on 07/05/2023 16:49:02

For some while I have been working on the Tailstock Support to be used in conjunction with the Emco Dividing attachment. I used it recently to make the Eccentric Spindles for the Emco Compact 5 and Unimat 3/4 Lever operated Clamping attachments. One of the Eccentric shafts is being set up in the above photograph.

The Tailstock body is made in to halves for ease of manufacture. The split line is easily seen in the above picture. Two Button headed dowels locate in the central Tee slot. This automatically locates the tailstock on the same centre-line as the Emco unit. Which also uses two button headed dowels in the same tee slot.

The tailstock barrel is locked by two brass half pads using the adjustable clamping lever. The barrel currently looks a little over-long, and this may well get shortened sometime in the future, once I have had a chance to use the tailstock a bit more.

The interchangeable centres uses the usual Unimat location technique but the dimensions are the same as the earlier Unimat SL. I had thought of using the U3/4 dimensions but this would have led to a larger tailstock barrel. This can be a problem when working on smaller pinion gears. Where the gear cutter fouls the tailstock barrel.

Regards

Gray,

Hi Colin,

Thanks for the kind comments as regards the design.

I have never considered the need for the void filling. Plus with the C5 tailstock, access is required from below to get to the two set-screws used to locate the tailstock barrel and lock the feedscrew bearing.

The design of this attachment will not allow the tailstock to droop when you move it. The lever action allows just enough clearance for the tailstock to slide when released. It is a bit like just slackening off the clamping plate on the standard set-up to allow the tailstock to slide. Unfortunately using the standard set up to do this usually results in the clamping plate jamming, due to the turning moment on the plate.

It is funny but this design actually came about because of a YouTube video on converting a Proxxon Tailstock to lever clamping. This involved machining the tailstock body, (a big No-No with me, which I have proved is not needed). Which combined with the sloping back face on the tailstock of that particular model and the oversize bore used. I considered not to be a real proposition on the C5 especially as the two internal ribs which take the camping forces would be virtually machined away.

The beauty of this design in use is that I can release the locking lever with the third finger of my Rt hand. Move the tailstock with my thumb, index finger and second finger, then re-lock again using the third finger. One slick operation which makes using the machine so much more enjoyable. Plus makes me more efficient in my work time. (By the way the lever ratio is 30:1)

At first glance I can see no reason why this type of attachment would not fit these lathes, and I had considered mentioning this in the previous post. Of course I would really need to have access to a machine, or machines in order to make a proper appraisal.

Regards

Gray,

Some while back I promised a Lever operated Clamping attachment for the C5.

This shot shows the attachment fitted to my Tailstock salvage scheme. This still uses the same lever, eccentric and eccentric pad. The standard attachments do not require for the standard tailstocks to be modified in any way.

As I said earlier, what fits the C5 will also fit the Unimat. Above are the component parts to complete the conversion on both machines.

This shows the sculpting required to miss the internal strengthening ribs.

This shows the C5 parts assembled and fitted to the Unimat 3 for convenience as regards photography. Below with the tailstock body fitted. No more searching for that Allen key, or having the key foul the topslide if the key is left in-situ.

Lastly we have the Unimat base fitted to the lathe.

Because the C5 tailstock body casting fouls the Leadscrew handwheel on both the Unimat and the C5 it will not slide on and off the Bed. The Unimat tailstock casting does and the whole unit can be removed at will once adjusted. Here is the attachment waiting for the tailstock body.

Here is the Unimat tailstock completed. As these attachments sit on the bedway in their own right. When the tailstock body is fitted the whole unit slides up and down the bed with a nice silky feel. The attachment also ensures less debris can enter beneath the tailstock to bed interface as the design clearance is only 0.05 mm (0.002"  )

This concludes the Modifications to the Compact 5.

The only other item I am considering making is a Motorised Toolpost spindle, but as this is a separate stand alone attachment, it will be probably be described in a separate post.

Regards

Gray,

Edited By Graham Meek on 21/04/2023 17:12:34

Hi Robert,

I wrote this up as an article with EiM back in Nov 2013, pages 149-153.

I may well have submitted this to MEW many years ago, but I do not recall it being published. I know I have several items still waiting to be published with MEW, this may be among them.

Unfortunately the timescale between submission and actual printing does nothing to help with my memory.

Regards

Gray,

The problem with all these types of caliper knurling tools is the Overhang. The adjuster placed between the pivot point and the knurls reduces the capacity for a given size.

In true Blue Peter style here is one I made earlier.

The adjustment is near the operator, out of harms way. Due to the force application point there is an actual mechanical advantage over the standard caliper knurl. The arms holding the knurls are much shorter thus they do not magnify the sideways movement. Not that hey can move sideways due to the construction used.

Capacity 0-50 mm, and it works straight out of the box, hence why I make my own tooling.

Regards

Gray,

I am all for keeping costs down, that is why whenever possible I make my own tooling. That way I know the tool is done to an acceptable standard to me.

The tool shown could be improved especially if the bolts used for the pivots are just plain set screws/bolts, that is threaded up to in under the head.

Reaming out the holes to the next size up and fitting Shoulder screws would be a good move. Shoulder screws can be made or purchased. As would fitting shims either side of the arms to make the joint a closer fit.

Generally,

Lastly there is a trend to fit large wheels in the knurling tools these days. The old school sizes used to be 0.5, 0.625 and 0.75 "or 13. 16 and 19 mm approx. These wheels have less area in contact with the workpiece, they need less force to get them to cut, or more correctly deform the workpiece.

One only has to look at the rear wheel of a tractor, where the size is such, so as to lessen the impact on the soil.

Regards

Gray,

This is what knurling should look like. Click on the image to get a closer view.

Contrary to Sonic's text book I always start with the knurls off the work. That is after first touching the knurls on the diameter at 12 and 6 o'clock and applying a cut to the knurls with the adjuster incorporated in the knurling tool. The work should always have a chamfer to lead the knurls into the work.

The faults in the above OP's knurling are more than likely due to sideways play in the knurling tool arms. There needs to be no lateral movement at all. The pivots should be a true diameter and not the crests of a threaded bolt like so many that I have seen. Poor fitting pivots contribute to the lateral movement.

By starting on the work as shown by the OP, each wheel will adopt its preferred position. Which will be anything other than in line with one another. As I said recently on the same subject the knurls are no different to helical gears with the same forces acting upon them. This is why in the above shot by Petro1Head one knurl is predominate.

Regards

Gray,

Edited By Graham Meek on 31/03/2023 15:29:42

Most re-sharpening services in our area use CNC grinders which grind the cutter all over. Years ago you could stipulate just grinding the gullet which preserved the O/D to a certain degree.

I have found resharpening a coated cutter not only gives a keener edge than the as supplied condition, but it will still out last a standard HSS, size for size.

Regards

Gray,

I received mine a few days ago and my wife received hers several weeks ago.

Regards

Gray,

Thanks Martin, I had not considered making a case, but it would be nice to give it a good home.

Regards

Gray,

I have finally managed to finish the Multipurpose Clock stand. The clock fitted in the above photograph reads 0.002 mm and was a given to me by a friend. When using this in my Starrett Scribing Block I could seldom get the same reading twice. The weight, stability and improved locking mechanism on the above clock stand has made it all worth the effort. The clock now gives the same reading time after time.

This next photograph shows the Slider to Read-out connection. I am indebted to John Slater for this suggestion. It is piece of Pinion Wire and allows the two units to move laterally independent of each other. I am also indebted to Ketan for supplying the DRO after an enquiry for a drawing. As I have stated previously this was only added as an after thought on my part. The mounts for which are dead easy to make.

This shot also shows Locking Knob which works on a separate shaft and thus does not influence the clocks setting. The Locking pad is spring loaded which always ensures a constant pressure on the rear face of the Column by the Slider.

This shot shows the Handwheel in the inboard position which gives a direct, or rapid traverse.

Pulling the Handwheel out engages a reduction drive of 4:1 for slow traverse and clock or DRO setting. The traverse is taken care of by an MXL toothed belt sunk into the Column. There is a tensioning adjustment incorporated in the top belt anchorage.The belt being sunk into the column ensures the teeth are always kept clean. The drive I was expecting to be a little Notchy but in the end my worries were unfounded.

This check was to verify the perpendicularity of my work. Running the DTI up the side of my homemade Cylinder Square and then turning the Cylinder through 180 degrees showed no error. Which was very satisfying.

The DTI can be mounted in the Vertical and used to check heights of components. Both as a comparator or in conjunction with the DRO.

This shows the scriber fitted for use as a digital Height Gauge. It takes literally seconds to change from one to the other. The scriber proper is a separate piece bolted to the end of the holder.

Finally checking the perpendicularity of the Proxxon Milling machine Column. While the clock position is not ideal and no reading at such an angle could be trusted. Using the clock in conjunction with the feedscrew does give a quantifiable reading. Which in this case was a lean backwards of 0.03 mm over 150 mm plus of vertical travel.

Given the weight of the milling head this will probably rectify this error.

I hope you have enjoyed this little device.

Regards

Gray,

Thank you all for responding to my request, I had the figure of 7.2 mm stuck in my mind, but it always pays to check.

Regards

Gray,

I was wondering if there are any Unimat SL users on the Forum.

I am making a tailstock support for my Proxxon/Emco Dividing Attachment set-up.

I was hoping to use the same size centre mounting diameter at the Unimat SL, which I think was 7mm or slightly over.

Can someone confirm this size for me?

Regards

Gray,

Edited By Graham Meek on 18/03/2023 11:05:29

And just as I was getting used to this site, Good Luck,

Regards

Gray,

Not wishing to put another stone in the ashes, if you will excuse the pun.

Stone and brick buttress walls are usually laid with the courses running perpendicular to the buttress face. Which means the courses are seldom horizontal and usually slope as the wall does in the OP photograph. Any slippage of the masonary will tend to be towards the abutment face and not away from.

I surmised it may have been a ramp. It could also have been part of a larger structure that was taken down to a level where it was deemed safe. Or to a point where the wall was considered safe to build on, alas we will never know.

Regards

Gray,

From what I can see in the OP's photograph it would seem the Knurls have been presented to the work in the centre of the diameter to be knurled.

This is not something I would do.

I have detailed my method elsewhere on the forum under a similar heading. Perhaps one kind Moderator might provide a link?

The pattern shown in the workpiece left by the wheels leads me to think the axles are not parallel to the work axis in both the horizontal and vertical planes. (This may be a defect in the tool construction, or mounting). This is a critical requirement with scissors knurling tools. Also critical is the side to side movement of the arms of the knurling tool. Each wheel is fighting to move sideways due to the resultant forces involved. The wheels are no different to a Helical Gear and these need to be paired in a gearbox to cancel out axial forces. Any play in the arms will therefore be exploited by the knurls at the expense of the finished knurling.

Small diameters usually benefit from straight knurling.

Regards

Gray,

I would agree, but I had envisaged the top surface of this particular wall to be the walkway. What we don't know from the photograph is how far these stones extend into the wall.

It may well be the ramp surface was wide enough to get a sack truck or cart up, and the width included the top surface of the wall, we just don't know. Feathered stones would tend to crumble under a heavy load.

Regards

Gray,