Member postings for John MC

Lead boots? Me? Not in the family car, the wife would have something to say about that!

No I haven't kept them long enough for a belt change, guess why?

Not convinced that the belt debris is responsible for the wear elsewhere in the engine. That sludge will sit in the sump, if any gets picked up by the pump won't the filter hold on to it?

Reminds me of when the Japanese introduced motorcycle engines that the engine, gearbox and clutch shared the same oil. Dire warnings from the less knowledgeable about clutch lining material destroying the engine......

Change my footwear? Don't follow. The Eco referred to the cars economy of ownership, according to some sales lit I have when I first bought one, needs some translation from "sales speak" to english but I think I am right.

In the video posted by Steve, did the guy give an indicaton of mileage. I skimmed through the video so may have missed that. I would suggest that was a neglected engine, judged by the amount of c**p in the sump.

I have had three Fords with that engine. All have been reliable (so far!) but have not really lived up to the "eco" bit of the name, that is to say not as economical as I would have liked, especially the one with the auto gearbox.

Is that the correct use of an apostrophe? Or "there".

Found what appears to be the same product for £158 (delivered) on Amazon. Time will tell if its any good.

The only reason I can think of for Warco charging well over double the price may be that it will bolt straight on to their machines, no setting up needed?

Does anyone buy at these prices when, typically, they are usually sold for well under £200?

Its the characteristic finish when the tooth form is generated rather than formed.

To finish off my previous post I size the drilled pilot hole by multiplying the hex AF size by 1.02 and the square AF size by 1.06. Never an exact size so I round up to the nearest drill size. I arrived at this by trial and error (and a few broken broaches!), when I first made the tool. Some years later I found these factors are about right, maybe a little generous according to some rotary broach suppliers.

I note that the Hemingway version of this tool calls itself compact, I would suggest it is not that compact. That is to say it is overly long. On a lightweight machine overhang needs to be reduced as much as possible. The cutting forces are not truly axial so will try to push the cutter off centre. Keeping things "short" will be of benefit. With this in mind I would also suggest mounting the tool with a morse taper rather than a parallel shank in a drill chuck.

This version of the tool also uses 3 bearings (I think), one of which is a thrust bearing. Omitting that bearing would reduce the overall length by a useful amount.

I like Neil's idea with regard to the design of an external broach. I have a number of components to make that will have a 9mm AF hex, worth a try I think.

I make the smaller, 2 - 4mm AF, hex broaches 0.05mm bigger than nominal, 5, 6 and 8mm 0.1mm bigger. 10 and 12, 0.15mm bigger. This gives one, maybe two, chances to sharpen. For imperial, the equivalent. From memory I've used similar allowances for square holes. Ultimately it wil depend on how accurate the hole needs to be, for an allen key these allowances are okay. Again, from memory, I think the allowance on the larger sizes could be even bigger to stay within acceptable limits.

For the smaller sizes, if I needed to broach a large number of holes I would buy HSS broaches, I break more silver steel ones than I wear out! For the larger sizes hardened silver steel works well enough, I've managed 6 and 8mm in EN8 steel.

I generally drill the initial round hole a little larger than nominal, I'll have a look at my notes and reply tomorrow.

John

I've been using a rotary broach I made for some 30 years now, internal shapes, hexagonal and square mostly. The cutters for the basic internal shapes are straightforward to make, how will you make the external shape cutters?

Easiest way would be to buy? Quite expensive.

If I were to make a rotary broaching tool now I would make sure that I could buy HSS cutters that would fit. I make them from silver steel, okay for softer materials but struggles with small AF's in steels.

John

Keep going when you are able Taff, you will hve a fine machine in the end!

I've helped a friend sort out exactly the same problem on a Seig X3. An error of ~0.15mm across the table (Y direction).

At first we thought the table had distorted but checking the ways, which were flat, suggested otherwise, possibly a machining error?

A local machine shop confirmed the hump was on work side of the table. The machining to correct was done on a surface grinder. Two steel bars were placed on the magnetic chuck and ground flat. The ways were then placed on the ground bars, there was enough "grip" from the magnets to hold the table for grinding.

Many thanks for the replies. I was hoping that I could use a 3 volt power supply, the sort that looks like a fat 13 amp plug. As has been suggested, the electrical output is noisy, the device won't like it. Also, my understanding of these PSU's is that they need to be made to "work". That is to say, the very low power demand of the DRO may not be controlled very well by the PSU.

I wonder if using one of these powering a voltage controller may still have problems with electrical noise?

At the moment I am favouring a larger battery to power the DRO. I'll need to make a dummy battery with flying leads.

My last thought would be to use a mains USB adaptor connected to a voltage control device, (as in the previous post). Would this be electrically clean enough?

I use several of these types of DRO in my workshop.

Powered by a either one or two 3volt button cells (CR2032). These batteries never seem to last long so was wondering if anyone has made them work from a suitable 240 volt to 3 volt mains adaptor.

Anyone got any ideas for doing this?

John

The excessive overhang from the lower spindle bearing seems to be a generic feature of this style of machine. It will, without doubt, hamper the performance of the machine. It would be so easy at the design stage to eliminate this unneccessary overhang. Could it be done so as to incorporate driving slots for face mills and the like? Very necessary on large powerful industrial machines that are made to work hard but our machines don't need it.

My first go at reducing overhang reduced it by some 35mm, that is to say the bearing was 35mm closer to the load it is supporting. I achieved this by maching away the overhang until the spindle was almost flush with the end of the quill and what was now the oil seal holder.

Then I remachined the 4MT to bring the various chucks etc as close as possible to the end of the spindle. This, of course, made the drift slot redundant. A tap on the drawbar unlocks the bearing.

The photo shows the setup for machining. The spindle mounted in its bearings in the quill. The steadies holding the quill so that the spindle runs in its own bearings. This ensures absolute accuracy. It was fortunate that the spindle had enough "meat" in it to allow modification.

The machine was reassembled and put to work. The improvement was noticed immediately. By way of a comparison I used the machining of the head adjusting device I described earlier. I machined some of it before and some after the spindle shortening work, this made for a good comparison.

I wish at this point I could say I was pleased with this but I cannot. I could not help but feel what I had done in reducing the overhang was a "half a***d" job.

Look at the photo of the machining setup, the lower end of the quill is a big lump. The bearing sits some 15mm from the end of the quill. While the spindle was dismantled for cleaning up after the work described I took measurements of the quill, spindle and other components related to the assembly. Then drew the assembly on the computer. I have now reduced the overhang by a further 21mm. This will mean (I haven't done it yet) a new spindle and modifications to the quill. I'll describe this when its done. I've only just ordered the the steel (EN8) for the spindle and bearings. There may be some further gain, I need to see the bearings "in the flesh" to see how the cup and cones of the tapered rollers fit together and determine the space needed. I think SKF's recommendations look rather generous.

Incidentally, the original quill is case hardened, not really necessary, I think, especially as the morse taper surface and the splines were not hard! The spindle did not machine well, a hardness test revealed that the spindle was just over 200 Brinell, so not much harder than mild steel.

As an old colleague would say, thats made from old park railing!

I have a Brother P-touch E100, a self contained device rather than needing a PC. Makes a nice label, plenty of options available. I'm not sure that the labels it makes will have the long term durability of the traditional Dymo type.

My only complaint is its appetite for batteries, a mains adaptor sorted that out.

Time to sort out the "nodding head" error. To recap, the head needed 0.008" (0.2mm) shim trapped between the head and Z axis slide to bring the quill perpendicular with the work table.

After gettting a friend to check my reasoning/method I clamped the slide to the work table of another mill. I shimmed it in such a way as to duplicate the shimming that corrected the error.

A fiddly job manipulating the cutter around the spigot!

Before machining I checked that the spigot would not jam as it would be misaligned. A bit of trig showed the error was very small and as I mentioned before, when I improved the fit of the spigot I left some clearance to avoid jamming when the clamp bolts were released, just as well I did!

Reassembled and checked the accuracy. Remembering the error was 0.008" (0.2mm) over 6" (150mm). The error front to back (Y axis direction), is now ~0.0015" (0.04mm) across the full width of the table, 9.5" (240mm). Happy with that for now.

What I wasn't so pleased about was creating another error to remove an error. In my defence, it was the easiest way. Ideally the metal removed to correct the error should have come off the head casting. That would have stretched my facilities and been a diificult to set up.

To set the head vertical "tramming" as its called here, wasn't easy. The head is a big lump of metal to nudge very small amounts. To make this easier I made the device in the photo. Hopefully it's operation is self explanatory.

Only useful for the vertical (or near) position. The round bar can be unclamped to move out of the way for any other angle.

Another mill of my aquaintance has a geared arrangement (worm and wheel) to rotate the head. I considered this, lots of work to do, maybe for the future.

At this point the machine got some more use. All seemd well except for the excessive overhang of the cutter from the the bearing that is supposed to carry the cutting forces. I thought it was limiting the machines ability to remove metal.

In reply to the previous post, the original method of locking the bearing adjustment is unsatisfactory so I have just applied good engineering design and practice to sorting it out. To rubbish this style of locknut without understanding why it caused a problem and why another type apparently sorted it does not sit well with me.

Anyway back to the Cormak. The machine was now back in one piece, any problems so far were relatively easily sorted.

At this point I fitted a two axis DRO to the X and Y movements. I decided not to fit to the Z (column) axis, this is for positioning the head, the precision movement is done by the quill. I hope my reasoning remains valid!

I fitted a basic DRO to the quill and was delighted by the fact I could get it fitted within the head casting, just.

I also connected the VFD using the existing switchgear box for the VFD remote controls.

The round bar adjacent to the dro is for oiling the quill and its bearings. Its screwed in to an existing hole in the quill guide and protrudes through a hole in the cover. An oil cup screws in to the top of the bar.

Time to get the machine running. To start with I ran the machine at various speeds checking nothing got hot, all seemed well.

Before cutting metal I attempted to set the head vertical. Difficult due to its weight and poor location. Managed it eventuall but began thinking of ways to make it easier, more on this later. Setting up the head did show a significant error. Side to side good. Front to back and error that would need 0.2mm (0.008" removing to correct. The 0.2mm error was over a distance of 150mm.

The error I found in the column had reduced somewhat. Over the full movement of the column, assuming my large angle plate and cast iron box are accurate, the error was under 0.04mm. Not much over one and a half a thou. This was both for side to side and front to back. Pleased with that.

I ignored this error initially and did a few jobs on the mill. Not.hing like a some big cuts to settle things down! Allowing for the known error the machine seemed accurate.

The machine has a 4MT location for my various chucks etc. I noticed that the ER40 chuck was hanging out the spindle by some considerable distance, excessively so. This needed to be sorted out. My first thought was to make compact chuck that would locate on the O/D and end face of the spindle. Couldn't get a useful reduction in overhang. Also would not help with other tooling. So I shortened the spindle, I'll describe that later.

The machine was now showing some promise.

Something not right there. Assuming it was a Boko metalworking machine, these are substantial machines, it would take a lot of force to distort the spindle to introduce an error. Where was the bearing adjustment ring? For rigidity at the top of the spindle? Probably some 300mm separation? Clamping the adjuster upsets run-out at the cutter end? If the KMT's ability to be tightened selectively to reduce error then that error needed to be investigated.

I would strongly suggest the error was elsewhere.

I did consider useing a KMT style locknut, axially too long, not enough room to accomodate. Also, it would be clamping on a splined part of the shaft, it might clamp on the thread, it might not.

The locking ring I have described is very effective. Easy to make, the accuracy is easy to achieve, clamping/adjusting face perpendicular to the screw thread when machined at the same settting. Made properly, once the adjustments made it will not upset that setting. I hope your comments do not put others off using it.