Member postings for jonathan heppel

Yes Tim that's definitely the Gucci way of doing it- arguably the "proper". Thing is, washers get lost, in which case plan B. Thanks for the next size down tip- I didn't think there was room.

Thanks for the replies. The Whitworth Society is looking into it for me but I thought there might be some members here with personal experience. They did tell me of an early 7/8W bolt with a 13/16" BS nut so I feel a bit more digging will confirm my suspicions that the practice (if not formal standard) changed twice.

Ian S C I agree with you up to a point but considering Sir Joseph's zeal for standardising and this being a high tech RN warship engine they will have been made to an existing standard. There are some surviving yellow metal small head nuts but since they are ratchet specials it's unwise to draw conclusions.

If true it does have implications for scale modellers, of course.

Ps I should have said that they are all hexagons.

Edited By jonathan heppel on 08/06/2014 16:30:17

The British standard for Whitworth nut sizes famously changed mid 20th C to the smaller size used for BSF, which size curiously also appears for coarse threads on at least some Victorian machinery. Does anyone know if this practice was common, or perhaps even Sir Joseph's original standard, leading to the irony that modern nuts are actually the "correct" replacement.

Perhaps there was even a choice of the two.

If anybody who works on old machinery has anything to say I'd love to know- I'm currently drawing an 1855 marine engine whose fasteners have disintegrated but it seems there is only space for the smaller size.

Ps by old I mean 19thC before the first BS of 1908.

Edited By jonathan heppel on 07/06/2014 15:20:28

Did some about 10 years ago for 1/4" bore out of a 6mm HSS engraving cutter blank on offhand grinder and angle grinder held in a vice. Material was 316. Neutral rake worked just fine. Job's been working (dymamic, not static) 40 hrs a week ever since. Diameter is the critical dimension with O rings, width is more about type of duty but anyway is less important. Surface finish must be adequate but nothing special. It's easier than first appears.

Edited By jonathan heppel on 25/04/2014 22:56:02

Maybe too far west but Exe Engineering in Exmouth might be worth trying. Long and distinguished history, good machines and staff.

As already stated, it's worth remembering that industrial speeds are maximum limits and are geared towards maximum production even if at the expense of shorter tool life, since tools are cheap and machine time expensive. Also those for HSS presume flood coolant. In the home workshop the priorities are usually reversed, and flood coolant isn't universal. Reducing to half or two thirds of industrial speeds makes a very considerable increase in tool life. The only caveat with carbide is to run fast enough to stay out of the built up edge zone.

Why the C3 clearance? If you're just following factory recommendations I wouldn't bother. Such a tiny amount would make very little difference to the service life of the bearing, if that's your concern. Doesn't C3 refer to the clearance between inner and outer race? That would be a tricky job indeed, and well worth £20.

Arc and Arrand it is then. It'll be interesting to compare them. I think I was being too pernickety about not wanting to extend them. I frequently use adhesives at work but still have an irrational prejudice. Stupid of me.

Thanks for the replies. The largest Arrand available is now 1" only. Perhaps no more are being made and stocks are running low. It's funny that we now regard Arrand as pricey when back in the day they were the budget replacement for J&S et al. How times have changed. Still would prefer the new stuff to be more consistently better though one can't have it both ways I guess.

Thanks, Brian I tried Arrand but they don't do one with a big enough head diameter. I realize that you have to be trying quite hard to mess up such a simple thing but after a less than optimum experience with collets I thought it might be worth asking at least if there were any differences. Other than head size the obvious qualities are truth and hardness. The mating taper is only a stub type and I don't want to risk damaging it. I repaired some jewellers' swaging rolls recently that were through hardened, glass hard and brittle. Shattered as a result There is a reason why Arrand kit is more costly. I'm ordering one for one of the critical jobs and going cheap on the less demanding ones

I want to buy some morse taper blanks for some tooling. I've always made my own when necessary but hardened shanks are desirable. Besides, they aren't expensive these days. There are many suppliers but are they all the same? I'd rather pay a little more if they were higher quality.

Any suggestions?

Why are taper mandrels used with an arbor press? English as she is spoke I guess.

I've just started learning Draftsight which is a free 2d prog from the solidworks people. Good beginner's manual, well supported, online tutorials. Give it a go- it's really not too hard once you get started. You've got nothing to lose but a little time.

They're great if you have a repeat job like the one above, but for only a few not really worth setting up. I took mine apart and put the tap chuck and friction clutch on a direct morse shank to power tap in the lathe. Best used with machine taps of course.

Check out RS components stock numbers 222-3823 and 222-3801. and others in the family. If appearance is important, they're really tidy.

Try pneumatic suppliers, or perhaps Lubetec (may be Lubetech)- not to be confused with a spillage control company with a similar name. Air stuff is generally push fit these days, but compression fittings are still available. Also SMC make cute M5 secure barbed fittings for nylon or urethane if plastic line is ok. RS do them or used to.

As Alan implies, if you're not hardening the expander then silver steel isn't the best choice. For similar jobs I've used a normal HT bolt or (better) a socket cap as stock, which is half hard and cheap even new. The ideal material is probably case hardened mild steel.

High speed and deep enough cut is generally the key to finish. You must generate enough heat to take you out of the built up edge zone, or work below it as suggested on this forum not long ago.

Small machines always benefit from higher rake angles and dead sharp tools, and like Douglas Johnstone I've achieved good results on gummy materials with ground tips for aluminium, but only for finishing to close limits cos I'm tight.

Or ignite the swarf.........

Slideway grinding leaves the telltale marks that you have in your high areas, which is purposely done to provide oil reservoirs as in flaking. I suspect you slide was milled, then it distorted due to stress and was finished on a slide grinder. The distortion was more than the grinding tolerance allowed, hence your little problem, and why the "good" finish is low.

As far as bearing surface finish is concerned, it is quite true that when the surface speed is enough to promote hydrodynamic lubrication, a "broken up finish is unnecessary. This never happens on a manual machine tool, and squeezing out the oil film and the resulting adhesion which causes stick-slip becomes an issue. This is why it is rare to see two finely ground mating surfaces; fine scraped or surface ground finishes are usually mated with the traditional slideway ground finish or a polymer bearing material, whose finish is usually broken up also because of said stick slip.

It's no big deal but there's rather too much blue there to get a good print.

Edit. looking at the print again, there isn't too much; it's just not very good contact. Would benefit from a few passes with a scraper. My mistake.

Edited By jonathan heppel on 23/02/2014 18:30:19

It's the other way round. Scraping is an extremely expensive process. Not just the man hours, but the temperature controlled factory space in which to work. For this reason, I expect it will be totally obsolete in a few years for new builds, but check out the Dixi site. (Super precision Swiss borers- they are very proud of their hand finished machinery) Rich King has been spending a lot of time in Taiwan teaching scraping classes because their premium machines are still hand finished, though their cheap stuff is farmed out to the PRC. There must be automated processes, but they don't yet have hegemony. No old files either- power scraping machines and carbide tips, though it seems the Swiss pull style still uses steel, even just carbon sometimes. There are some good you tubes and also threads on US forums.

Dixi site says 500 hours of scraping per machine! Still if you want the best..........

www.diximachines.com

Edited By jonathan heppel on 23/02/2014 00:29:29

Edited By jonathan heppel on 23/02/2014 00:34:20

Edited By jonathan heppel on 23/02/2014 00:40:13