My little engine (continued)

[James BParticipant @jamesb]

Hi Garry,

That looks to be silver soldered on the shank.

I have found that the very thin cutting discs (1mm) in a small angle grinder are perfect for cutting tool steel.

This is essentially a tangential type tool – so the centre drill / tool steel would be mounted on the end of the shank at a small angle giving you the relief angle at the front.

Then you grind the top edge flat to give a cutting edge – parallel with the top edge of the shank for brass (zero rake) or at an angle for steels.

James

[GarryCParticipant @garryc]

Hi James

Thanks, you've clarified some really useful info there. Great timing as i'm about to have a play with making some tools shortly – have to do some digging now to see what I need for silver soldering..

Hi Peter

I do make quite a bit of mess sometimes – promise!

Regards

Garry

[GarryCParticipant @garryc]

Can I ask if someone can confirm that the little 'chamfer' (if thats the right word), arrowed below, is done with a small round nosed tool on the Lathe? Just wanted to double check, thanks.

Hoping my HSS blanks will arrive today and think this is what I'll have a go at making first as I can't seem to do without one…

Cheers

Garry

Edited By Gary on 11/06/2015 10:11:56

[JasonBModerator @jasonb]

Yep, its just decorative so you could do your own thing with what cutters you have or leave it off.

[GarryCParticipant @garryc]

Great thanks Jason, that then looks like an ideal straightforward test of my efforts at making a small round tool…

Cheers.

Garry

[GarryCParticipant @garryc]

Taken a bit of time out to have a first go at some proper tool grinding – some rather poor photo's of my attempt at a knife tool below – having a go tomorrow at a round nose. This will have to be case of trial and error and trying to improve with practice i think..

Wasn't sure to put these on here but then thought its all part of learning my way through the engine build. I'm not saying the tool is right yet but it will be good to try it and see first hand what needs to be changed and I have to start somewhere.. I did try and use a protractor on the angles once I had the basic shape which was really useful. I'm definitely going to like tool grinding, thought it was great fun!

All photos of the same tool..

Cheers.

Garry

Edited By Gary on 12/06/2015 19:18:12

Edited By Gary on 12/06/2015 19:27:31

[Neil WyattModerator @neilwyatt]

I would always try and make the cutting edge as near as possible the original corner of the HSS (OK you have to grind a tiny bit away). I've never found the lack of back rake a problem, even when doing light facing and it mean you can sharpen by grinding the end without changing the tool height. My mini lathe suits 5/16" high tools, so I use 5/16HSS, although now I have a QCTP its a bit of an academic question.

Neil

[GarryCParticipant @garryc]

Thanks Neil, that sounds like good advice – I have ground far too much away…!

One of the diagrams I had in front of me doing it was this one below and it shows exactly what you are saying I think – with the top edge of the cutting blade almost exactly the same line and height as the top of the tool..

I'll have it in mind now after your comments and should have a better idea of what to aim for next time, for this tool type at least..

Regards

Garry.

[GarryCParticipant @garryc]

Just a quick few photo's of my efforts this morning at the round nose tool, hoping someone will shout at me if it looks like a disaster waiting to happen..

Took just a few minutes to do, much easier than the knife tool – but maybe thats because it needs more work….. 

Tried to stay off grinding the top down this time..

Thanks

Garry

Edited By Gary on 13/06/2015 08:40:12

[GarryCParticipant @garryc]

A chance to try out the round tool I made this morning, it wasn't too bad at all..

I did the small chamfer first and then as it seemed to work ok I had a go at putting the waist on the bearing..

It's ok I think, I could maybe have gone a bit deeper though..

I'm glad I had a go as again it was good experience and I think it looks better for it..

Cheers.

Garry

[GarryCParticipant @garryc]

Its my time of the year to get the garden straight again (almost there) – but still managing a bit of progress..

14mm slot so far just left to do a 9/16 pass..

Cheers

Garry

[GarryCParticipant @garryc]

Have the fork gap to size now. Over the weekend I'll have a go at the Hole for the crosshead Bolt. I thought to do the Bolt at 5/16 as I have a reamer that size and as Jason suggested move the locking pin hole out to 13/64, I think that will be ok with the new size bolt but will double check before I do it". I have some 1.5mm drill bits (but not good ones) and as there is no pin material supplied thinking maybe to use the shank of one of the drill bits for the pin..

Bit wary of the small hole in this material to say the least..

The round end not to size yet, will do that on the rotary table later..

The Con Rod Drawing.

The Crosshead Bolt Drawing.

Cheers

Garry

Edited By Gary on 19/06/2015 09:58:41

Edited By Gary on 19/06/2015 10:14:41

[JasonBModerator @jasonb]

Do you not have an old scrap end of steel you could turn down for the pin? even an old 4" nail would do.

J

[Anonymous]

Gary: Looking good! I might have drilled and reamed the 5/16" hole before slotting the fork end. As for the locking pin I'd leave it were it was and just file a slot in the connecting rod. If I was being really fussy I'd mill the slot. No-one is going to see it once assembled anyway.

Andrew

[GarryCParticipant @garryc]

Hi Jason

Thinking about it yes I do, I've got some 3mm or thereabouts mild steel bar – I've not tried turning anything like that small a diameter before though, 1.5 mm sounds tiny! I don't think I would fare too well with the indexable carbide tips I've been using up to now as they seem to do as much 'pushing' as cutting I think – but a good chance to try my new knife tool that I made – that's sharp enough to cut your finger on…….looking forward to having a go already..!

also fingers crossed there won't be any broken drill bit photo's here over the weekend..

Cheers

Garry

[GarryCParticipant @garryc]

Thanks Andrew, I had a job to make up my mind which to do first as I thought I could see pro's and cons both ways but had a feeling to go with the slot first in case the hole alignment went out after the fork material had been removed – its very useful to hear you may have done it the other way though as I know now its a viable alternative for similar things in the future.. Great to pick up on things like that on here from people that know – I would have likely stayed in the dark over that one otherwise..

I wouldn't have thought to mill a slot for the pin either – it may well help me out of trouble if things don't go as planned.

Ta very much!

Garry

Edited By Gary on 19/06/2015 11:37:54

[GarryCParticipant @garryc]

A couple of photos of todays progress – just the remainder of the drilling done. Ignore the curved ends they are still untouched and still as cast (having a go at radiusing them with the rotary Table tomorrow)..

The drilling went ok, I had assumed I could use my slot drills in doing the crosshead hole but the only one I had without a shoulder and long enough was a 6mm so I used that one to make sure all was square going across the fork gap, it seems to have worked out fine. The photos make the gap to the 'pin' hole look massive but to the eye it looks very close.. I'm glad I took Jason's advice and moved the hole out to 13/64"…! The Crosshead Hole is reamed at 5/16".

Using the 6mm Slot Mill to make sure all was square over the fork gap.

The Crosshead hole reamed to 5/16".

Drilling the 1.5mm Locking Pin hole – at 13/64" from the centre of the Crosshead hole.

I'm still very heavy handed in getting marks on the work – these are left over from the Lathe Dog. Have to try and get better at preventing this.. This the opposite side to the Locking Pin face.

The Locking Pin side.

Next to radius the ends with the Rotary Table.. I'll have a go at turning the 1.5mm Locking Pin when I'm doing the Crosshead Bolt..

Quite pleased I didn't have the problems I thought I may get today doing this..!

Cheers.

Garry

Edited By Gary on 20/06/2015 14:41:10

[GarryCParticipant @garryc]

Almost done dare I say..

There was quite a bit of material to come off the ends I thought..

The radius is a little larger than it should be – I wasn't sure if I would come back onto the 'flat' if I used the exact measurement – need more practice to see how that works…

I used an end mill and milled down (i.e. not side milling ) with light cuts – not sure if that's the right way but its working ok so far..

May have chance to finish later..

Cheers.

Garry

Edited By Gary on 21/06/2015 12:54:18

[GarryCParticipant @garryc]

Couldn't resist had to go finish it…

I think there has been more work to make this one part than any I've done to date (I'm counting it as one as the parts had to be made together) – brilliant to have got through it without any terminal mishaps, just one silly mistake with the taper really and the other from not reading the drawing fully but I can easily sort that out ( if needs be, it may be ok) when I come to fitting, all part of the fun! Few cans for me now this afternoon by way of celebration..!

All needs a good clean up and polish now – think I'll be stuck with the dog marks though, have to count that as another mistake if I'm counting really. My first real go with a rotary table attempt at an accurate set up, just a simple one here but I have it my head now in seeing how things are done, helped a lot by the explanatory drawings posted here earlier.. Very satisfying and a nice thing to work with.. My efforts with my old (tiny) table were more guesswork I remember..

Just put together quickly not tightened up and oops I see one of the nuts upside down..

Great little project in its own right & think I've learnt lots just from doing this one part..

Cheers and many thanks again to everyone for all the help given, I would't have got here without it.

Garry

[JasonBModerator @jasonb]

Looks good, what bits next?

[GarryCParticipant @garryc]

Thanks Jason, think it will be the Crosshead, Piston Rod and the Crosshead Bolt to look at next. I've only had a quick look so far but it looks like when Andrew Smith wrote his guide booklet Stuarts were suppling the Piston Rod and Crosshead as a single casting (unless I've read it wrongly) – so he won't be much help at all this time I think .. The Crosshead looks like an interesting shape and another challenge! But I really haven't looked at them much at all yet – been too much focussed on the Con Rod.. I'll start trying to understand it all tomorrow..

The Piston Rod and Crosshead Drawing.

The Crosshead Bolt Drawing. No its not meant to be bent – a bad photo..!

The supplied materials – The Piston Rod is Stainless Steel the others Mild Steel. I've read Stainless Steel can be difficult to work with..

Cheers

Garry

[GarryCParticipant @garryc]

I've been having a go at the little 1.5mm diameter locking pin and although I've managed to make one that is probably quite useable its not very good as it has a taper due to deflection when turning (no support without a centre in) – its only about 5/16" long and it has a 3 thou taper which is a bit hopeless I guess really.

So I thought to use a travelling steady and do a piece an inch long to part off from thinking I could have the tool immediately behind the steady – which I can but then discovered that on the next pass having wound in the steady to the new smaller diameter the length that you can turn each time gets progressively shorter due to the steady coming up against the new shoulder each time – I can easily make a better job of this short pin now I hope by having the steady further in front and staying up on the larger diameter or even by just having a centre in – but I was wondering if i'm missing something or likely being a bit dull here – if I wanted to use the travelling steady to turn along a long length I can't see how it would work with the turnable length decreasing each time with the steady being wound in each time to maintain contact as the diameters decreased..? If you put the tool in front of the steady then you have the same problem with the shoulder at the tailstock end..?

Sorry its early, maybe that doesn't make much sense – I'll have to do some reading up on using it later…!

But in case someone can understand what I'm trying to say and can put me straight – thanks..

Garry

 

Edited By Garry_C on 25/06/2015 07:19:09

Edited By Garry_C on 25/06/2015 07:24:10

[Clive HartlandParticipant @clivehartland94829]

Garry, a 3 thou. taper over 5/16", it sounds as if you are running the lathe too slow. Small diameters need a faster speed and a sharp knife type tool, perhaps with the corner slightly radiused.

Clive

[GarryCParticipant @garryc]

Hi Clive

Yes I was running very slow! I had it slow to slow down the auto feed I think about 250 rpm – I'll try much faster and hand feed and see how that goes, thanks!

Garry

Edited By Garry_C on 25/06/2015 07:40:46

Edited By Garry_C on 25/06/2015 07:41:00

Edited By Garry_C on 25/06/2015 07:41:17

[JasonBModerator @jasonb]

I'd be doing that at 1000rpm or more and your tool geometry and height become more critical as the dia of the work reduces. I would not be using the tipped tools that you have for this.

Also if you still get deflection take a second cut at the same setting to work out any spring in the work.

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