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Member postings for Clive Brown 1

Here is a list of all the postings Clive Brown 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Loose table on Fobco Star
25/06/2022 19:39:16
Posted by Dave Halford on 25/06/2022 18:00:28:

Below is the last paragraph on the first page of Tony's site, which might go some way to explain the quality issues.

According to an interview conducted by the writer with the Company's owner, Fobco began by machining parts, under sub-contract, for the makers of "Progress" brand drilling machines (distributed through the Elliott Group) as well as a much lighter, cheaper model for use by amateurs that was retailed exclusively through the London mail-order department store Gamages. However, after visiting the London store and seeing the retail price, O'Brian realised that the profit made by Gamages was several times that achieved by himself and decided to enter the market on his own account - and so the first Fobco "Star" drill came about, designed by his son, Frederick Thomas.

Edited By Dave Halford on 25/06/2022 18:00:46

I think that's a bit unfair. The opening sentences praise the high quality, precision and smoothness of the Fobco product. If the same basic machine was sold for over 40 years it couldn't be too bad.

Thread: Info' that might be of use to Warco Lathe owners.
21/06/2022 10:57:25

+1 that a carriage lift of 0.018mm is not really significant, but I wonder if the quoted measurements are wrong. Th OP refers to using a feeler gauge of 0.015mm inthe gap. If such a thing exists, I've never seen one.

Thread: Replacing a 24V AC machine lamp
18/06/2022 18:46:38

Not helping a great deal, but Iunderstand that halogen bulbs are, or will shortly be, banned for sale for domestic use. When I recently looked to replace one, I found none in the normal retail outlets. It's LED or nothing it seems

 

Edited By Clive Brown 1 on 18/06/2022 18:48:26

Thread: 'Mechanics' Weekly Magazine 1946
17/06/2022 19:34:56

Under their 1000 class list of castings etc. Reeves 2000 also list links to 2 downloadable pdfs of the construction series which you may be able to use.

Thread: Governor drive belt
17/06/2022 08:48:52

On my recently completed ST Williamson I used nitrile o-ring cord from e-bay, about 2mm dia. cut to length and joined with superglue. The joint seems reasonably durable though it's only a dummy govenor and I don't run for extended periods.

Cutting the cord should be done with a scalpel blade or similar to give good square ends.

Thread: Centaur Valve Timing
16/06/2022 13:59:52

Thank you all for these further thoughts and comments which reassure me considerably. This is the first IC engine that I've built so I have no real experience to draw on. Whilst I did think that the valve overlap etc seemed strange, ETW's reputation made it difficult to ignore "the words and music" despite the inconsistecies. I will now set the valves to what seems sensible positions.

A good tip about ignition timing.

MichaelR; a very nice engine, hope mine turns out somewhere near that result.

Once again, many thanks,

Clive

15/06/2022 19:56:24

Frank, thanks for follow up, seems we're both in the same boat. With me it's both valves, and the inlet shows greater difference from spec. than the exhaust.

15/06/2022 14:35:33

Thanks gents for quick replies;

Jon, I had read ETW's build notes re lost motion in the valve train, i did mention tappet clearance in my post but the timing differences I'm seeing are too large for this I think.

Hopper, My mearurements are with a scale on the flywheel with a dti on the rockers as you suggest. I agree that the follower geometry will affect the measured valve lift for any given intermediate position of the cam lobe, but, for a roller follower at least, I can't see it altering the angular positions of the start and finish of the valve movement. Those positions coincide with the roller crossing between the base circle and the two cam flanks, which are tangents to that circle. This angular distance is fixed by the cam shape itself. In your post you seem to suggest that extra angular distance might result, whereas I'm seeing a shorter opening period, this with virtually no clearance in the train.

Bricky, you say your engines work, why are you considering new cams? I'm thinking along that line with the Centaur.

Clive

15/06/2022 11:35:07

I'm in the process of setting up the valve gear of my Centaur gas engine. Having made the cams to drawing, I can't achieve the specified valve timings. Both valves have opening periods that are too short.The drawings are shown below.cams.jpgvalve timing.jpg

The inlet and exhaust cams lift over 220deg and 240deg. resp. and slightly less if tappet clearance is present The timing diagram calls for 240deg. and 250deg.Which is correct, does it matter much or have I got this wrong? Since ETW was a very respected designer and the Centaur is a long established design I'm surprised to find this apparent discrepancy. Comments would be appreciated.

Thread: Issue with fire tubes blocking up 3.5" Rob Roy
13/06/2022 18:07:07

Hi Tom,

if you haven't already done so, can I suggest that you give Welsh steam coal a try. Not too widely available these days but it can still be obtained.It's listed on Ebay, although I haven't bought any from there. In the past when I have run my Simplex on it I found the ash and clinker residue considerably less than with other domestic coals so it might improve your loco's steaming.

Thread: Loose table on Fobco Star
11/06/2022 13:21:26

Just measured. Clamping my Fobco table closes the slot by 0.008" to 0.010" so if your hole over-size is much above that figure then clamping is going to require a lot of torque on the handle. As said, there is a possibility of fracturing the casting assuming, as probable, it's cast iron and not cast steel..

Although not a simple solution. it might be feasible to put a split-clamp through the casting between the column and the table itself, although the table would tend to interfere with the clamp handle

11/06/2022 11:09:01

I've owned my bench Fobco for 40+ years, and throughout that time I've done just as you have. The casting is very rigid and it seems that the slightest wear will cause this looseness and the standard ball handle is a puny affair only about 3" long. An easy mod. hasn't suggested itself, there's not really enough metal in the casting to fit a split clamp. To avoid making it any worse I do try to minimise the number of times that I need to adjust the table height by having several pieces of wood of differing thickness to put under the vice/workpiece if safe and appropriate.

Edited By Clive Brown 1 on 11/06/2022 11:09:49

Thread: Failed Miller Transportation
04/06/2022 16:04:12
Posted by not done it yet on 04/06/2022 15:56:3

Does that really matter?

I would say that it does. That person/ organisation has the contract with the carrier and therefore the legal right to discuss responsibility and possible compensation, although we don't actually know if the transportation arose from a sale or just a re-location of the machine.

Separately, some effort seems to have been made to support the machine in the van. Strange how delivery seems to involve a pallet differing from the original one

Thread: Buried-cable detector
04/06/2022 15:57:09

I bought one of te cheaper brands from a DIY shed. My need was to detect wall studs, I was not very impressed. Positional indication was vague, tapping the wall with my knuckles seemed just as good. When I tried it for mains wiring results were just as unimpressive. I certainly wouldn't trust it to avoid hitting a buried wire.

Thread: The Correct Way To Sharpen Drill Bits Using A Picador Drill Sharpening Jig With Custom Base
02/06/2022 16:51:26

I very occasionally use the side of my grinding wheels although I can fully see why the practice is frowned upon on safety grounds. But irrespective of this, surely a practical problem with regular use of the side of a wheel is the difficulty of regular dressing to maintain shape and cutting efficiency. Setting up a jig to routinely use the side of the wheel will run into this difficulty. Isn't this the type of job that cup wheels were invented for? They're all side!

Thread: Advice on Belt Tensioners
02/06/2022 15:46:37

I find myself wondering why the OP wants a variable speed drive on a grinder. I understand that grinding wheels are best driven at their optimum speed. Too slow and they run soft and wear quickly. Too fast is dangerous. If the speed variation is to allow for different sized wheels then great care is needed to avoid mistakes and over-speeding.

Thread: Warning buyer beware
31/05/2022 16:21:49

Glad to hear the OP seems to have resolved the issue, albeit without the item he wanted. Looking at what I believe is the listing, the seller shows a fairly sizeable feedback score and at 100% which makes this problem rather surprising.

I joined Ebay some 20 years ago and my experience has been very good, the couple of problems that have arisen in that time having been quickly and amicably resolved at no cost to myself. The vast majority of sellers seem very keen to avoid negative feedback but the one in this case seems to have fallen from grace.

Thread: Stuart Williamson Engine
29/05/2022 21:43:28

My Stuart Williamson is now completed. An attractive little engine, it seems to run well and I'm pleased with it. The Cumbrian connection is an interesting bonus.

Can't seem to embed an actual video so here's a link.

https://youtu.be/-8ehkqaZBQU

Sorry about the noisy compressor..

Edited By Clive Brown 1 on 29/05/2022 21:46:18

Thread: slipping chuck
18/05/2022 14:49:35

The Jacobs chuck on my Fobco did show a tendency to detach if, say, too high a speed made a largish drill chatter. A dab of Loctite stopped that. Now been OK for several decades.

Edited By Clive Brown 1 on 18/05/2022 14:50:10

Thread: Easy power tailstock feed for your lathe
09/05/2022 09:01:30
Posted by Bill Kunz on 09/05/2022 02:14:27:

Many years ago I came up with a simple power feed arrangement for the tailstock on my 9" South Bend lathe when drilling, reaming, tapping, etc..

I'd question the desirability of a powered feed for tapping, especially in a fairly small lathe.

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