Member postings for jaCK Hobson

To improve edge holding, steels may include alloys to promote hard carbides. Micro-hardness vs macro hardness. At an extreme, think of plasticine rolled in shattered glass. Also an opportunity for more pedantry. These carbides tend to make it harder to get a fine edge.

Modern japanese tools tend to be a thin piece of hard steel welded to a fat soft metal like wrought iron. The thin hard steel can still be bent so you can true up a plane blade edge by tapping it with a hammer - the hard steel bends and is held bent by the soft iron.

I slapped on a 2 axis glass scale DRO from 'Vevor' for £109.99 on my SX3.5. Bargain.

Ender 3 v2 (what I got) - cheap entry. Plenty of routes for upgrade if you like fiddling with software, firmware, hardware.

Prusa - hassle free, easiest route in. the Mini isn't much more than an Ender 3 but it is limited by size.

My opinion is that auto bed levelling is well worth getting. A slight bother to fit for Ender 3.

Choice is cost vs hassle.

I also guess that is right decision for EN8.

Some things to consider: being plain carbon I suggest you just need to get to 'at least' the hardening temp, but exceeding it can still work. The lower carbon means it is farter way from the 'eutectic' so will need a higher heat to get the max out of it. So getting it beyond 'cherry red' is probably a good idea. For small items in low alloy steel, you do not need to hold the high temp for long at all - just get to heat then quench immediately. If hotter and held longer then you will get grain growth which will make it brittle. (For some higher alloy steel, an exact temp is much more important to get the desired composition of things before quenching)

The spec sheet listed by MichaelG suggest a max hardness of less than 26HRC which is way below 'skating file' hardness (which for decent files is above 60HRC). So I guess that means it is not intended for applications above that and should be tempered to get that. The tempering temp is therefore quite high at about 600C... too high for the kitchen oven where I usually bake my stuff. That might be beyond purple and then colours start to get very inaccurate.

You can probably buy it in the 26HRC 'tempered' condition and machine at that hardness.

The 'brittle' behaviour could be due to longer heat and/or lack of high temp tempering.

Wear will be increased if the pinions are not polished as well. It will be much easier to polish a soft EN8 than a hard silver steel. Lots of other things contribute as well to wear - like dust, or the other material, or the gap, the maintaining power etc.

So if you are of the opinion that hard pinions are good... go with silver steel. It is specifically designed for machining and heat treat. But I think it has a characteristic of being quite large-grained (might be to help machining). It also has extra carbon to create gritty carbides which also resist wear but will cause the wheel to wear faster.

If you are not convinced of the need for hard pinions... EN8 without hardening is going to be much easier to machine and polish.

All theory, no practical experience in EN8. I read a lot of books though.

Edit - Martin posted while I wrote. I am in complete agreement with everything he writes. Some might find contradictions with what  I wrote, but I don't think there are.

Edited By jaCK Hobson on 05/06/2022 13:54:39

You might not need a full set? If just one, I'd go half-round.

I guess all good files will be prone to rust as the requirement is for very fine grain in the metal and stainless isn't great for that.

Cheaper Vallorbe are excellent. You pay more for a finer cut. Cut 2 should be a good starting point.

Heat treating 01 is really simple - the metal is designed to be easy to heat treat.

I want that!

I have had a vfd die and a couple stop working but come back to life after opening up and dusting with a brush.

I now have VFD in a large enclosure covered by a cloth.. .e,g, on a middle shelf with cloth pinned across the top and bottom shelf, or in a plastic box with cloth draped over it.. No problems since doing this. The forced air enclosure above is better and smaller and looks pro, but as a quick soln, simple works (I've been running like this for years).

I got a heated vest/gilet which works very well. Mine has a heated collar which is nice.

Edited By jaCK Hobson on 28/04/2022 13:31:37

I couldn't get on with Octopi until I ran the pi from the Ender power supply. The stepper motors caused too much noise.

So now I run the 20Vfrom my ender supply into a voltage converter to drive the pi. No comms problems since...

What a fun day! Not as busy as previous years but that meant that the visitors could really engage. I didn't get a chance to take a break so managed to bore many people with long explanations of active damping applied to my 3d printer.

I don't think there is anything quite like this anywhere else. The South London Branch of the BHI is probably the biggest. I'll try and give more warning next time...

I think morrisons etc is fine for most visitors - I think 3 hour limit. Worst case, move the car from one to other - 6 hours!

If disabled then talk to the people at the soper hall barrier and you might get special treatment.

Unlimited parking is available up the road... but it is a bit less than a mile to walk back

Sorry about the website. That is an oversight

Edited By jaCK Hobson on 21/04/2022 12:25:29

I'm going to be showing off 3D printing on my table... Lots of other better exhibits. Should be a good day and maybe worth up to an hours commute - you will be able to spend more than an hour at the event without getting bored.

Thanks for the tip on using the draw bar to remove the chuck. Simples with some parallels. I used similar idea (3/4" pipe sleeve and bolt/washers) on MT2.

Deburring the R8 adaptor with a fine diamond stone got the total runout down to .1mm and .06mm measured of the J6 taper of the adaptor. I think it reasonable to expect .01mm on a reasonable quality adaptor so I will get one. .04mm on cheap 3 jaw keyed 16mm chuck is probably what can be expected?

I might buy another chuck for small drills...

Edited By jaCK Hobson on 29/03/2022 13:16:33

For comparison, I had a check of my new Sieg 3.5. This is the first time I use the drill chuck (which was supplied with machine as part of the standard package).

If I measure runout on a quality hss 10mm endmill held in 3 jaw chuck, I get in the region of .25mm runout. Not what I hoped for at all as it is clearly visible and not what I'm used to. Disappointing if I'm using 1mm drills, which was my intention. Any tips on how to get a chuck off a J6 taper so I can compare with other chucks I have? I suspect the R8 adaptor makes a significant contribution as it is not the same quality of finish as that of the separate 10mm collet I got at the same time.

Runout on the same 10mm end-mill in a R8 collet is difficult to measure - I think the movement on my .01mm indicator is due to lack of stiffness in the mill. So I would guess .01 or less. The collet is std from Arc - not std with the Sieg. Does any of this matter if the mill isn't that stiff? Applying hand pressure (maybe 5-7kg) to the head in x directon, with all axis gibs locked, gives .4mm deflection. Much more than I would have guessed.

I got no idea if any of that is good or bad. Not a clue, but I would be much happier if I hadn't measured it Can someone cheer me up?

Edited By jaCK Hobson on 23/03/2022 12:54:11

I think it is very unlikely you could ensure a high chance of detecting a knackered old lathe without personal practical experience of turning and/or tinkering on a lathe.

If you lack experience then you might not even know if the poor results you get from your lathe are due to lack of knowledge or a fault with the lathe.

Either buy new, or buy according to the direction of someone you trust and who has something to lose (if only your respect) if they give bad advice.

Big lathes are a bother to install.. but equally a bother to get rid of. If you want a big old bargain, get something smaller and cheaper to learn on.

This is stuff I have concluded after buying a few old lathes with little personal experience. I am an expert in making bad decisions; I should not be trusted to make good ones.

Machine shops will chuck big old knackered lathes in the skip just for the scrap value. 

Edited By jaCK Hobson on 13/03/2022 09:06:18

I finally have better credentials for reading 'model engineer' but only as a collector. I bought this...

Pretty sure it is an engine. It has inlet an exhaust and a suggestion of a fuel pipe/carb so I guess it was intended to be IC.

I think it has twin 'cylinders' (I bet they are flat, not cylindrical) that move towards each other on an arc with a single combustion chamber in between.

I also guess it is 4 stroke as there is some backgear and cam which means the 2 valves each operate on alternate rotations.

I don't expect it would ever work... the concept would seem to require accuracy and precision well beyond that which the evidence of build quality would suggest has been achieved. But somone has invested a lot of thought and time into making it.

As a bit or marketing, which I'm not good at, this is run by the 'South London Branch' of the BHI, which is one of the largest branches. I'm lucky to rub shoulders with world experts in their field... and there seems to be strong correlation between success and just being really nice to talk to. For pedigree, George Daniels was a founder and former president.

We had to cancel the last one because of Covid so this is a celebration of the new normal!

Free tea/coffee and cake. (No hog roast this time - a casualty of Covid )

Lots of displays that would be interesting to many on this forum. Workshop guided tour this time! I'm planning to have my 3D printer there so not just strictly horology.

I would guess this won't be as busy as last time but hopefully that gives more opportunity to 'engage', chat with exhibitors, 'have a go' etc.

Train station 50 yards away. Not far from J6 on M25. There is easy local parking for an hour or so.

The DRO works. Bargain.

X is neat:

I'm a bit worried about Y - I should really turn the scale up the other way to minimise dirt getting in (for now I leave a bit of extrusion resting on top).

Does anyone want to encourage me to turn it upside down, or do some people live with a scale this way up?

Tips for installation:

I started trying to complete the install without any dismantling of the mill but it is so much easier once you do! And tapered gib strips make is simples.

Again I am glad I got this size of machine and not any bigger - the cross slide is about as heavy as I would like to handle on my own without any assistance.

Thoughts on the SX3.5

The flaking paint issue is extensive on my mill. I was forewarned so I'm managing not to let it bother me. Be careful to check if paint is going to bother you!

The X power feed installation feels like it lets the side down. The electronics and motor are fine, but the hosing is thin plastic and will not last much longer. I have had to take the cover off a few times and if you put the wrong screw in, or over tighten, then the plastic cracks and that screw hole is then no good. I got 2 screws left holding the panel on... and they come undone because I don't want to over tighten like I did the others. I thin I will be 3Dprinting a new box within 12 months. The wire to the limit switch dangles around ... not sure what the soln would be though. The power is via a separate brick about the size of an old laptop power supply, and the power input socket has its threads stripped so dangles out the box. Note that there are extensive power supply options hidden in an enclosure behind to column so a nice soltion would to have been to provide the power from there.

The column is no where near as massive as it seems in the sales pictures - most of that is a steel sheet covering to enclose the power and electronics.

The Z power lift however is a nice install. Enclosed power supply, hidden wiring etc.

The quality of finish, including surface finish, tends to be good enough and no more. An example is the gib strip. Where you might expect a scraped surface, you have the same effect but achieved with a hand held grinder. The actual points of contact are probably less than 10 across the whole gib - but these are at the extremes so it does its job. I don't know what impact this might have on wear.

The rest of the wiring and circuit boards are all neat.

As far as being a good or bad mill... I have no idea as I have nothing to compare to. But if you are buying, then be prepared for the above and you will be much more likely to avoid dissapointment.

I went ahead and cut the glass scale with a slitting disc in the angle grinder. I got lucky and it cut perfectly. I had a lot of extra scale so had the opportunity to try multiple times. Worst case was 2cm of scale chipped out at the end.

I reckon there isn't anything special about the angle grinder - I would guess that glass just shatters under stress but tends to go across scale rather than along... which makes sense from a 'science' point of view. Band saw, hack saw, just snapping without even scoring... I bet they all work within 2 cm. I was 'careful' but that is only within the limits of how careful you can be with an angle grinder.

Edited By jaCK Hobson on 27/02/2022 13:53:28