Member postings for ken king, King Design

Hello fellow machinists, can you advise please ?

I have a Centec 2a with a vertical head, and when using the highest speed with small cutters (very low load) the quill head gets pretty hot, uncomfortable to touch in fact. I'm concerned that this may not just be a function of all that gear oil being thrashed around but something more serious, and I need to be sure that no damage is being done. I've never stripped the head, and have no information on maintenance, adjustment, lubrication schedule etc. , so if anyone out there has information to share I'll be very grateful.

While I have your attention, I'd like to obtain riser blocks to increase the clearance for chucks and cutters. I kow they have been in production sometime, somewhere, but haven't found any. Can you help with that too ?

Thanks in advance,

Ken.

Hello Rob, it seems that the two smaller items, if combined into one, would perform the function of the Clarkson nosepiece, apart from there being no obvious driving dogs. At any rate there would be a need for a collet to hold the tool, which would be tightened by the short taper in the central piece illustrated. I take it you have no collets ?

Regarding potential tool slippage, are there any driving lugs or similar buried up in the main body ?

Sorry I can't really help, I've not seen one like this, but I'll bet there are members who have. Hopefully they will come forward and shine the necessary light. Good Luck !

Ken.

This method came to me in a rare flash of inspiration triggered by the happy coincidence of having materials to hand. I needed to polish 1" bores, 3" long in bronze, following a lapping operation. In casting around for ideas I found an old roll of nylon pile draught excluder strip, 6mm wide and 6mm deep, the self adhesive backing of which was long-dead, but that didn't matter as it turned out. I also had some broom handle available, from which I soon turned a mandrel around 3/16" smaller than my bores, 5" long. Still in the lathe, I drilled two transverse holes, one near the end, the other close to the chuck. By doubling the end of the nylon backing strip I persuaded it into the first hole, pulled some through, and trimmed off, then wound the strip tightly onto the mandrel in touching turns, and finished by tucking through the second hole. The resulting brush looked the business, as they say, so it was lightly dosed with a paste made from green buffing compound and light oil. A casting was carefully threaded onto the brush as it was a tight fit, but a trial run at low revs built confidence and in a short time I'd polished all three bores . Result !! For the benefit of anyone having a similar need I've found a source on eBay, to which I have no connection whatsoever :-

The Culley Family Shop, [email protected], tel 0560 3449596 Five metres of 6.7mm wide, 6mm deep will cost you just £5.79, broom handle you can source for yourself, but be prepare to explain why the housebroom is suddenly shorter.

Here's an update on my problem. I had to rebore the castings slightly oversze to get rid of the worst reamer effects, encountering some work-hardened areas in doing so. I obtained some 1/8" thick copper sheet and made up an expandable hone to the design given by Ramon in his thread. I had bought on spec some Silverline Polishing Compound, on eBay, and when mixed with 3-in-1 oil it looked useful, so away we went, albeit with a little trepidation, after all, these were a client's castings !

In the event I found the whole process remarkably simple and controllable. I was able to bring all three bores to the same diameter (there had been just over a thou. difference between them after reboring) and true circularity and parallelism. Bores were checked using an internal micrometer, which in turn was checked with an external micrometer, reproducing the 'feel' of the bore. Thanks Ramon, and all who pointed me in his direction.

The next requirement was to improve the surface finish a little, and here a small brainwave struck. I pass it on in the hope it may prove useful to you. I found some old but unused self-adhesive draught excluder, 1/4" wide grey nylon fur on a nylon backing strip, and having measured the compression available I turne down a length of broom handle to a suitable diameter. I drilled a transverse hole near the end, and another near the lathe chuck. I folded the excluder backing to get it into the first hole, pulled it through and trimmed off, then spirally wound the excluder round the wooden mandrel, finishing similarly at the second hole. The holes were tight enough to hold it in place. Taking my trusty green buffing compound block I mixed scrapingsinto a runny paste with oil which was then dosed onto the fur. A casting was threaded on and subjected to a few cautious passes up and down the length of the mandrel. Inspection gave me the confidence to proceed at a slightly higher speed, and in a short time all three bores were showing a polished finish with a fine underlying scratch pattern from the honing, which I think may well be close to the ideal mentioned by some contributors to Ramon's thread, and mine too.

Let me know if this idea is useful,

Regards to all contributors,

Ken.

Hi Jerry, I too wouls suggest belt 'set' might be a contributory factor. I'd always had some motor vibration on my Myford ML7, then changed the very old belt to one obtained from my local friendly motor factor, and the vibration simply went away. Now I always release the belt tension when I've finished turning.

Lots of discussion going on in my other thread 'Honing vs Reaming', and I've finally got around to asking myself 'what surface finish is actually most desirable in the cylinders of a steam locomotive?' As I didn't have an answer I thought I'd throw the subject open to you all. An article from 1920 talks about a reamed finish 'like glass' and I assumed that is what I should be aiming for, but is it ? Isn't it likely to be influenced by piston seal material ? By means of lubrication, or lack of it , or other factors I haven't considered ?

Please give me the benefit of your experiences,

Thanks,

Ken.

To complete the picture, my particular problem arose when trying to ream 1inch diameter steam engine cylinders. I have bored them to within a couple of thou, with a very nice, uniform finish. I was using a brand new hand reamer, not an adjustable, and the first bore reamed ok., though not as good as I'd hoped The second was a disaster, with the reamer digging in and jumping from one tooth to the next, six jumps per rev, equal to number of flutes. I never thought of dulling the tool edges; that's kind of counter-intuitive isn't it ? Maybe that would be the answer, but why didn't the effect arise with the first cylinder ? I'm reluctant to put the reamer anywhere near the third and final bore, I think understandably, and that's why I started thinking about other means of improving the surface finish from fine boring to polished.

Well Stub, my interest stems from recent unhappy experiences with reaming 1" bores. I'm awaiting more info but I think there are some preconceived notions of what can or can't be achieved with honing, and that it may prove to be a suprisingly versatile technique, capable of either rapid metal removal or very fine finishing. As I learn more I'll post it here for all to absorb. Here's another question to test understanding:- What's the difference between honing and lapping, or is each an extension of the other (do they in fact overlap - ouch, sorry),

Regards to all,

Ken.

Hello Roger. I should say that the only way to avoid dents is to not inflict them. Once in, virtually impossible to remove. I'd suggest belt or orbital sanding to clean surfaces and remove small blemishes, flipping the material frequently to treat both sides in parallel (no pun intended). If you can find a vacuum pump and make a simple, flat, vacuum hold-down table it will be well worth doing for the convenience it brings. Suprisingly, supported thinnish MDF provides a good surface and allows sufficient airflow through its structure to act as desired without the need to drill perforations. Just mask off the area outside your job with parcel tape or similar.

Sanding, particularly with fine grades, will harden the aluminium surfaces somewhat, which can be useful or annoying, depending upon your intentions.

Good luck,

Ken.

Does anyone out there have experience of honing small bores ? Can you recommend suppliers of various grade stones, from rapid metal removal to polishing? So far I've come across Sunnen, a Swiss company who trade worldwide. I'm calling their U.K. office on Monday next, but would like to know of others, and discuss the relative merits/problems/costs of the technique. Can you contribute ?

Thanks for further tips guys. All good helpful stuff and appreciated,

Ken.

Thanks for responses. M-machine now live in my Bookmarks bar.

I should have said that short explanations of each photo appear in my album Yellow Sun. they have not transferred with the photos to this thread.

For some reason unknown to me, but perhaps obvious to others, the photographs appear in reverse order to that in which they were entered, and so give a step by step 'deconstruction' of the model. Just go to the end and work backwards. I'll do better next time. Thanks for looking.

'Yellow Sun' is the name given to this bomb, and the model was requested to help illustrate talks on 'The Cold War'. It is made of light alloy throughout, to 1/24th scale, and is 2" diameter and 10 1/4" long. A dimensioned sketch was supplied, which I augmented by careful examination and perspective scaling of some photographs of bombs on their trolleys, adjacent to a Valiant and a Vulcan.

The simple body shape comprises two distinct sections: a parallel front end housed the warhead and supporting hardware, including significant electrical power supplies, whilst the rear is a stright taper carrying four stabilising fins.

The surprising flat nose was deliberately chosen to keep the dropping speed subsonic, in order that no shock waves would form and disturb the operation of the barostat triggers, set to a detonation altitude.

This model is of a later version with american designed warhead, using ram-air turbine generators to provide electrical power during descent. The earlier all-British design employed half a ton of lead acid accumulators which had to filled with electrolyte and charged before flight - hardly a viable rapid-response technology.

Dummy fin roots were fitted into fin slots whilst the body shape was turned, then discarded. A plug threaded into the tail end had a centre hole for in-lathe support, and was later shortened into the finishing truncated tailcone.

Can anyone please suggest a source of accurate 1/8" steel plate (not 3mm), either G.F.S. (expensive) or some other description which fits the bill. I'm looking for enough to make four bolting plates, each about 21/2" x 31/2" . Slightly thicker plate capable of being surface ground to thickness would also be acceptable.

Thanks for all the inputs so far. There was me thinking one single standard answer would be echoed by all, but it seems there are as many methods as respondees. It has been helpful though, so thanks again.

Yes, I can see that an adjustable reamer would work on larger holes, but 0.125 ? I should also add that the clevis ends are 0.125 apart, so not much distance with respect to tapers either. Actually, I've never checked a tapered reamer to see what the diameter difference would be over such a short distance. At the smaller side, a lightly tapered hole is no bad thing for the press fit, but to make the other side parallel, well, I can only think of the tip of a machine reamer, which has very little lead-in, but that's two reamers for each clevis size and £'s begin to add up!

I have some loco parts to make and on the drawing several of the clevis ends have one side specified as, say, 0.125 dia. whilst the other side is 0.124, the idea being that a press fit on one side retains the pin. Fair enough, but can someone with more experience please explain how this is best achieved ? I gather it's not an unusual feature so presumably there's a tried and tested method. Please help !