Member postings for James Hall 3

Jason B: Ah, I hadn't thought of tramming the head with the locating pin removed, so that's a very helpful suggestion - having removed any misadjustment there I can proceed to check the column, as you say, with a known good square.
Should it come to it, do you know if the column dowels have a lead-in chamfer - I'm very lairy of withdrawing dowels where realignment can be difficult, I've been caught before.
Adjustment of the column gib is something that has given me difficulty: tightening up enough to remove all play results in binding and the head lowering in a series of jolts. Reference to ARC elicits the response to make sure that both top and bottom adjusting screws are snug - but this I do. Funnily I can still feel some play on the jib side when all play has gone from the other.

Thanks Jason B. Yes, the locating pin for zeroing the head is far from precise, and I've been able to get rid of errors by tweaking the head rotation position in the past - but things have now gone beyond that - I know not why!
I tried using the head to raise the column as you suggested, but before any appreciable lifting of the head I got a very alarming noise of the pinion drive for the Z leadscrew jumping out of mesh - so gave that up very quickly.

Here's another newbie question:

When milling using the side of end mills (particularly on steel) I get a slightly 'wavy' or 'rippled' finish; this is not confined to one particular cutter or size.. I'm pretty sure I'm using the correct rpm for the cutter size and still find this despite varying cut depths and feed rates or combinations.
Can you old hands throw any light on this, please and advice on overcoming the problem. The effect is shallow enough that it can be sanded away but would prefer not to have to.

Checking with an indicator confirms my suspicion that my SX3 mill needs tramming; shows approx 0.10mm discrepancy over about 300mm of table on X-axis and 0.02 on Y-axis.
While light weight compared with more 'grown up' mills the head and column of the SX3 are still heavy enough to be non-trivial when it comes to raising them enough to insert the necessary packings - has anyone advice on this - would be much appreciated.

Simple answer: YES.

Not to mention the sheer stupidity of making Russia richer and damaging ourselves through these misbegotten sanctions.

You could look at it as having a reservoir of heat waiting there to get your CH off to a running start.

Otherwise, why not simply program your hot water to start heating a short while before your CH - then the HW circulation valve will be shut by the time the CH comes on and your problem will be no more.

Thanks to everybody for some helpful responses. Got some 1/8" gauge plate and had a go - cleaning up the column mouldings for my Stuart beam. I started small with just the bead and then on to the rest. First attempt failed as the iron machined my tool - insufficient heat when hardening - judged by eye, next attempt used a magnet and all was well.

Pic shows the result, which I'm pleased with as the casting was very poor quality, very oval, ill-defined, and full of sand pits (some of which remain, but it will be painted) - at least it's round now and the mouldings are properly formed. I'm now confident to further make and use form tools as and when required.

Seems difficult to find cones - almost all people selling step drills advertised as cones, but not at all what is required. I eventually purchased a taper end mill (half as much again as a cheap cone but has already done more work than the only cone I ever owned and which blunted at the mere sight of steel), which easily produced relieved holes and allows very fine control of the hole size for beads etc.

I'm aiming to produce some finials/ball shaped ends around 3/16" diameter and proportionate length - also some half-round mouldings of around the same size to decorate stanchions. This seems a good opportunity to develop my skills as a machinist into making and using small form tools.

However, I can't find any guidance on the thickness of gauge plate to use - presumably there's a trade-off between robustness of the tool and the amount of work required to produce an accurate profile with appropriate clearance angle (i.e would obviously be ridiculous to make a tool of this size from 1" thick plate, but 1/8" might not be rigid enough).

As usual, advice from those with experience would be much appreciated.

Mike: I recognized the price of a replacement 10H flywheel having had to buy one last year - the original having irremoveably welded itself to the stub mandrel I used for turning the back side. Ouch.

Dalboy - Nice looking pen.

Thanks for the responses.

As a long-time wood turner I'm used to filling (made) grooves with an epoxy/metal powder mix using copper, brass and aluminium to simulate metal inlays and should have thought of this as probably the best solution. In my experience the metal powder needs to be as fine as possible else the polished finish can tend to look a little powdery and 'glittery' - and as Jason B says the epoxy needs to be as loaded as possible. I expect the cleaning up of the castings will give plenty of opportunity to produce fine powdered CI!

The beam flywheel is actually listed by Stuart at £38 + VAT + postage - money which could better be spent elsewhere, if I had it, I think.

A now deleted response pointed out that the flywheel on 'the real thing' would not have been polished anyway which, together with this post, has made me think rather more about the finishing of models in general - perhaps I'll bring this up in another thread.

Newly enthused by finishing my first model (Stuart 10H) I'm about to embark on a Stuart Beam kit bought second hand from another reader.

The flywheel casting has some pretty noticeable casting pits - big enough to warrant filling IMHO - returning to Stuart is obviously not an option.

Presumably one of the metal-containing epoxy fillers would be the thing to use but as a comparative newby I'm not sure what would be best to get the optimum colour and finish to match a well-polished rim - a dull patch might look as bad as the original pit.

Advice from you old hands would be welcome.

A Happy and Prosperous New Year to everyone.

Thanks again JasonB.
Not sure of the exact vintage of my 10H, but I got it on Ebay and had plainly been living in someone's attic for a while. It's old enough to have the cast crankshaft.
If needs be I'll finish the crankpin with emery, though pride and the challenge say that I should try to machine it to a finish. I'm wondering whether, as an alternative to emery I might lap it: a simple lap should be easy enough to make, or using the big end (which can be progressively tightened up as it is split) hence lapping the two together. I think that I can take the bulk off the inner faces of the crank webs and the pin with my heftier HSS parting tool and the try various strategems for finishing it while still over-size to see what woks best (this worked well with the rest of the crankshaft).

Paul Kemp:

Thanks to you too for your response which gives some very helpful hints on machining a crankpin. I'll let you know how I get on!

Thanks Jason B:

I'd missed the relationship of the bearings to the centres of the bearing stud holes and, as you demonstrate, the wider projection will give a zero end float and just a little fitting. I'd based my misconception of a large end float on mounting the crankshaft but with the bearings not properly positioned axially. Beginner's mistake.

More question on tooling for machining the crank pin.- more newcomer's ignorance I'm afraid - so please bear with me.

I have an indexable parting tool, but only c.1/16" wide do you think it feasible to grind away the centre? More generally one would have to use something like a diamond slip or very small wheel to do this. My inserts are gold coloured so presumably coated (TIN?) I suppose the underlying carbide is fine without the coating, but are there unexpected negatives to removing it - I have wondered about his in respect of other inserts and giving a little sharpen with a diamond slip as I would with an HSS tool.

I do have a more (unused) substantial HSS parting tool which would be wide enough to bifurcate but this, squaring the end, and small roundings to provide the fillets would obviously require a regrind to return it to its original function.

Sorry to extend my original question, but now seems the time to ask.

I'm well into my first model from castings, a Stuart H10, and (fingers crossed) all seems to be going well.

However, and it may be because I'm a novice and not practiced at reading engineering drawing, I'm puzzled by one thing.

The brass crankshaft bearings are asymmetrical - the turned portion on one side where the flat part is machined away shown as projecting1/8" and on the other side of the bearing as projecting 5/32". I can't see from the drawing whether the longer projections face inwards toward the crank or outwards.

Perhaps they are intended to limit end-float on the crankshaft but it would be pretty large either way round. I think that these bearings would be the same for a 10V so the same question would arise.

While I'm here, any suggestions for a tool to machine the crank pin - it needs to be fairly narrow bur has to project from its holder to the depth of the crank webs (i.e. the crank offset plus a bit).

Thanks for any advice that you can offer.

Hi Huub - yes, I'd spotted that review, though even to the inexpert eye the presence of exposed 100v DC and 220v AC terminals shows that this needs a good insulated enclosure. Plainly the motor casing (plus any other exposed conducting parts) needs earth bonding.

Fortunately I have a good friend who is a professional power supply designer and can advise on safety - in view of our shared concern I probably wouldn't consider buying this without such expert advice available,

Thanks for pointing this out.

I think that I'll go for your design Huub - but with a rather heftier motor so that at least the final shaping can be done with it as well as final sharpening.

This looks as if it might be a suitable candidate - currently at a very good price and, I suspect from its intended use, with bearings sturdy enough to directly mount a disc without a further spindle.

https://www.banggood.com/Machifit-ER11-Chuck-CNC-500W-Spindle-Motor-with-52mm-Clamps-and-Power-Supply-Speed-Governor-p-1027937.html?cur_warehouse=CN&rmmds=search

That's really helpful Huub, thank you.

I hadn't appreciated that your motor was 'dremel sized' which seems fairly low powered. Do you use your set up for shaping cutters from scratch - which would be fairly slow, I guess, or just for sharpening.

Thanks Huub and Paul.

As I don't speak Dutch I'm not sure of the grit size on those discs so it would be helpful to know that.

I'm more and more persuaded to go for Huub's solution, the main problem being finding a suitable motor to power it.