Yet another Quorn

[Charles Lamont]

My Mk2 Quorn Tool & Cutter Grinder kit was bought in 2004. It has finally emerged from under the bench and work has started. It will be mainly a Mk2, with pad/split-cotter clamps rather than split castings, some ideas from the Mk3, and numerous, mainly minor, tweaks of my own.

This job will proceed at my usual snail's pace, and I am not doing a full build log, but intend to post occasionally with more interesting set-ups, problems, wrinkles, ideas, questions.

The first alteration has been to move the column forward by 1/16" to suit the casting. The cored hole was really too big, and gave almost no latitude at all on the hole position, especially as there was a divot right at the top. I was lucky and the boring tool just managed to scrape all the primer off. Note on the far right of the first pic, a piece of blue plastic shim under the back of the angle plate to get it dead square to the spindle. Borrowing from the woodworking department, I was able to do a little preliminary blending of the chamfer into the cast surface.

[Admiral_dk]

Last Picture shows a new one for me - logical when you think about it - but I don't think I would have come up with this one by myself 

Per     

[Chipswitheverything]

Will be interested to see your posts about the Quorn build, and the ways in which you have gone about some of the set-ups for the more "interesting " operations that builders of this machine have the sometimes challenge of concocting. I must admit that, partly for the reasons I outlined when I wrote up my finally finished Quorn back in early 2023, my example has not done much since completion, but it was satisfying to have done the job. My various non-model engineer visitors to the house, seeing it proudly displayed on a table in the living room, have not sought to engage me in conversation about what it might be!  Dave

[Charles Lamont]

Boring the holes in the base castings for the bars.

The RH bed was fixed just by one bolt through its leg, so I clamped the back end to an angle plate for security. Straps are not practicable for this job as they are bound to distort the light Myford boring table which has to be free to move backwards and forewards between the two holes.

I went to the considerable expense of getting the longer, chrome-plated Mk3 bed bars from Hemingway. These turn out to be hydraulic cylinder rod, and they are within tolerance, barely, being evidently centreless ground and markedly lobed.

The front holes are bored very close to 1.000" - a good running fit on the bar, while the rear ones are 1.002" to allow 3 thou on diameter for Loctite.

As the assembly photo shows, I have nearly finished already.   

[Dave Otto]

Nice work!
If it is anything like the Universal Pillar Tool, once you get the basic machine done you are only about 1/2 finished

Dave

[Bruno Mueller]

I also used these hydraulic lift rods for my Bonelle. My rods were surface hardened and hard chrome-plated.

[Charles Lamont]

Six months after the last post I managed to get back to the Quorn.

During that interlude I have made the little instrument vice I posted a while ago, dug out and cleaned up the cam grinder and made some cams for demonstrating the thing at MMEX last October, and have completed the Power Hacksaw Refurbishment, also being reported here.

Now I can get back to the Quorn as No 1 job. I am trying to make an impression on the castings, having an extended session on the iron. I am doing a bit of work on each part, establishing initial datum surfaces and then putting it aside for coggitation before the next step.

Now, I decided long ago to use pad clamps rather than split the castings. For the best results, and following GHT's methods, the main hole is bored with the clamp pad in place. This means that the hole for the pad has to be made first. I am allowing just 1/64" clearance between the main hole and the clamp bolt, to give the clamp pads as much contact patch area as possible. I am finding it hard to organise proper datums on the castings so that I can be sure of getting the pad and main holes at the correct centre distance. There will be more on this shortly.

The next castiing to attack was the Workhead Base, two photos showing boring for reaming the 1/2" hole for the split pad clamp, and two of boring the main 1" bed bar hole. The angle plate and 123 blocks provide squared up surfaces to clamp against. These two set ups were infuriating because the casting is lopsided just where it sits on the packers, and every time I put clamping pressure on top, the blasted thing tipped over.

At the right hand end (left in the photos as it is mounted back-to front) I increased the bore very slightly as it can be compressed by clamping the Rocking Lever on to the rather thin walled seating spigot that is turned at this end. The main part of the bore finds the roundness faults in the front bar and is too tight in places. In boring I could hear some variation in the texure of the metal at different parts of the circumference. It will need a little lapping.

The final photo shows the Wheelhead Bracket being roughed parallel and square to unmachined surfaces. This has now been machined both sides to final width. I will probably follow the bible and make the spindle housing to finished OD to use as a gauge for boring the big hole.
   

[Krypto]

While I have no plans of making a Quorn grinder, I really enjoy seeing the interesting setups used to machine the parts.

[Chipswitheverything]

The Quorn casting machining is coming on very nicely, the shapes of the castings are certainly a test of patience and some ingenuity in holding them for the various operations.  I should think that every clamp, tee-nut and packer that I could find in the workshop was hauled into use at some stage when I was tackling them.  Your set up photos bring back to mind some of the rather laborious contrivances that I was "enjoying" playing about with ...  Dave

[Del_61]

I have built my Quorn using the mk 2 castings but to the drawings of Hemingway which has several modifications and is now called the mk 3.

I also built mine using the split cotter method and slightly longer bed bars of p.g.m.s. I have to say that "Time Saver" lapping compound was used on getting the final lapped finish on some key components.

There are lots of improvements and modifications to the Quorn design over the years, there is also a dedicated forum to the Quorn as well.

The most difficult part (so far!) Is the spindle. I decided that treppanning was way to stressful and built up these components carefully individually and loctited them together then finished them off on a specially made mandrel.

I still have to make up some bits yet, is a Quorn really ever finished?, but it was a challenge and has taken up about 5 years on and off.

I found a parvalux 3 phase motor from Ebay that I drive using a small inverter, but I am having significant issues joining the round plastic belt !!! All those difficult to hold, tricky castings and I cannot get my round belt to stay joined without the join failing. I might just buy a ready made one !

Good luck with the build, I made all the ball handles as it looks so much better, but I haven't decided if I am going to make the spiralling attachment though.

Regards

Derek

[Charles Lamont]

Well, you certainly did not want that Wheelhead Collar going walkies! Mine was the next to get some attention.

The first photo shows getting an initial datum surface, square to the body in two planes. Second photo, roughing the other end parallel to the first. After measuring up, both ends were finished to size, along with the little pads for the tilt adjusting screws. Next, it is set up square two ways for marking the hole positions for the clamp pad and the mounting pivots for the Wheelhead Bracket.

The fourth photo shows the casting packed up to centre height and set square with reference to the angle plate. (Setting square to the spindle means doing just that - with a turn round test. Traversing the cross slide past a stationary DTI tells you if the angle plate is parallel to the cross slide, but not necessarily that it is square to the spindle. Cross slides are mostly set on a new machine to turn a face slightly concave.) That hole looks as though it is too close to the bore. That is because the casting is intended to be slit through for clamping, but with pad clamps the hole needs to be closer in. The casting will be cosmetically dressed to suit. The hole may also look too close in because it is. Subsequent measurement shows it is 0.048" too close. Expletives.

I don't know how that happened, but it is going to have to be remedied. I don't propose to scrap it. Firstly, setting it up again is easy. Sat on the same packers, it can be lined up accurately with a 1/2" bar in the chuck passed through the hole, and can then be offset to get the hole in the right place using the cross slide dial. Boring bigger in the right place and fitting a sleeve would leave the casting too thin. What I mean to do is make an iron plug to go in the hole (to be fitted after setting up).

It will be no good pressing it in, because re-making the hole will leave the plug as just a thin crescent on the inner side. It would probably fall out. So, it will have to be glued in. But what with? Because the clamping pressure pushes outwards, fortunately the plug will not actually be subject to any load. Options I am considering are Loctite, JB Weld, and Araldite. Of these, I think Loctite in this situation may be a bit brittle and liable to chip in re-boring, and I think JB Weld may be too viscous to coat a thin joint that has to be assembled by sliding. I am thinking Araldite may be the best bet, as it will make a fairly thin joint and machines OK, but I would welcome thoughts.     

[Chipswitheverything]

Well, I must say that when I looked again at the forest of clamps that I'd used to hold down the Wh. Head casting, it did strike me as a bit frenzied : but I think that the idea had been to get a sure grip for the boring operation while not using too much clamping force at any individual point , so that the bore remained round rather than being slightly ovalized when the job was released. Probably! 
  Bit of a bind about the quite small discrepancy in the plug position, but I wonder, could you bore with the brass plug inserted in the present position, and make good with some minor dressing back of the plugs where they contact, and a similar small necking in diameter of the locking bolt to clear the column ?  Dave

[Del_61]

I use pieces of card or thick paper interposed between clamps, castings and the machine table. This provides better grip without having to result in overtightening the clamp or studs.

Regards
Derek

[Charles Lamont]

Dave and Derek, thanks for your comments. I agree on being careful about clamping pressure. I have a pack of redundant business cards that I use a lot for clamping, often as protection as well as for improved holding, though not when working to a dimension above the boring table.

I have been on Quorn Owners on Groups.io and its previous incarnations going way back, but there does not seem to be much traffic there of interest these days.

I don't know about making the belt joint. Are you using a guide such as a V-block for bringing the hot ends together? I am planning to use a little Poly-V belt on mine, H-section, 3-rib.

I have had a think about using the Wheelhead Collar casting as is, with a necked-down clamping bolt. I think it would work, but I am not sure I would feel happy with my workmanship. Plugging and reboring will be a more 'interesting' exercise anyway.