Stuart 'No.1' : a beginners tale..

I'm wondering if the misalignment will bore out in situ on the lathe cross slide. The finished bore needs to be 12.7mm. Since the bearing joint failed and I re-soldered I've had a boring bar through and the hole I guess would be about 8mm at the moment. The photos show the re-soldering has misaligned the bearing halfs'. I wondered what others would do - from the perspective of this being only an all time project no. 2 that is. I can't expect anything like 'brilliant' yet of course and should maybe see if I can get away with it and put it down to experience? Or should I redo?

This after the joint had failed and re-soldered - and me thinking I could get in with a small boring bar.

My smallest boring bar that would be long enough..

This would be the 'front face' in the housing. It looked much worse yesterday with all the re-soldering marks etc..

The front face again. 2.

This is the 'rear face' or internal face when in the housing - you can plainly see after re-soldering the misalignment.

In the housing - again you can see the misalignment on the housing 'block'..

In the housing - again you can see the misalignment on the housing 'block' 2..

In the housing - again you can see the misalignment on the housing 'block' 3.

I would be grateful for any opinions - from an all time no.2 project that is. I imagine many on here wouldn't dream of continuing with it, but remembering back to when you were starting out....?

I've certainly learned from it, which is always a good thing... Strangely I have developed quite a fond memory of some of Victoria's mistakes that still sit on the engine.. I have to improve on that though this time around..

Regards

Allan.

Edited By Allan. on 09/05/2014 10:37:21

Assuming that there is enough metal left to salvage the parts it's a matter of personal preference.

On my traction engines I've made complex parts again simply because I wasn't happy with the finish. On the other hand some journals on my two crankshafts are different sizes because I badgered up the machining on one of them. I decided not to buy a new casting and start again; I'll just bore the mating parts to fit.

Andrew

Alan Just bolt them firmly to the housing If they are solid they won't need soldering and as I said yesterday set the whole lot up either on the cross slide or on an angle plate on the mill then drill and ream

Roy

ps I wouldn't ream to finished size till you've done the crankshaft

Edited By roy entwistle on 09/05/2014 13:07:06

Hi Andrew

I'm thinking at the moment I'm best to carry on and see how the boring goes, will sleep on it. If that goes ok, its not going to notice that much if at all as the eccentric sits right in front of that bearing housing. The original fit was good and I know what went wrong and learnt from it - so there's probably little to gain by going over old ground and remaking, perhaps more important at the moment to keep going forward and learning more... The bearing is still a solid fit in the housing.

I'm puzzled at how bad it looked yesterday and before cleaning up this morning, it seemed much much worse than the photo's suggest now - must have been all the excess solder..

It would be good to see some photo's of your traction engine progressing sometime.

Hi Roy.

Yes after cleaning them up this morning I'm coming round to thinking to do just that (on the cross slide). But maybe boring instead of reaming....although if the drilling is much better when everything is bolted down I may try reaming..

Thanks.

Cheers.

Allan.

Edited By Allan. on 09/05/2014 13:17:48

Like roy say bolt them bown and bore on teh lathe, if the hole is 8mm at the moment then you will have enough to play with.

I'm also in agreement with Roy, I tend to do my crankshafts first and then do bearings, flywheels eccentrics etc to fit the crankshaft

If you are using those boring head type bars make sure there is enough clearance behind the tool. Another way to open them up is with a milling cutter, a 10mm would straighten up the wonky 8mm hole quite well.

Thanks Jason thats really helpful. Sorry I imagine these are dumb questions but does the following sound an ok way to go about things -

Drill a small hole in the other (blank, no hole yet) bearing then gradually open out using slot mills(?) to about the same as the other 'bad' bearing - doing this on the mill.

Then with the engine sole plate on the lathe cross slide use a slot mill to straighten out the 'wonky' first bearing hole - then bore to slightly undersize through both bearings.

I'm assuming I would slot mills for this rather than end mills?

Then on to the crankshaft before final boring of the bearings to fit..

A big thank you.

Allan.

Sounds OK but I would get the crank done then you only have to set things up once on the lathe.

As there is a pilot hole you could use 2, 3 or 4 flute cutters you don't have to use the a centre cutting mill such as a slot drill so you can use what you have to hand rather than go out an buy slot drills.

Thats great, thanks Jason. I'll probably get the bearings close first to make sure that all goes ok - but have to set up twice then on the lathe as you say...

It was while reading about possible problems drilling Gunmetal that I came across some info somewhere suggesting that a mill cutter was less likely to catch / grab at the work than a drill bit due to the side cutters (unless I misunderstood) - but had no idea I could make holes like this... so hence the attraction to try it this way..

I do have both End and Slot Mills..

Cheers.

Allan.

I regularly use slot drills for 'drilling' brass and bronze above about 10mm diameter. The reason that slot drills are less prone to snatch is most likely because the helix tend to be slower than on jobbers drills, so the cutting edge is less acute. I've got a few small straight flute drills for brass, although they don't seem to be available now. There are however slow spiral drills available specially for brass.

Andrew

Allan,

I must have posted this picture somewhere on the forum already, but here is the current state of the traction engines:

On the downside nothing has been done in the last couple of months, as I am swamped with work.

Andrew

Hi Andrew

Great photo, must be brilliant to work at that scale... ah one day maybe!

and it was interesting to hear that you are using slot drills for brass...

Cheers.

Allan.

Todays little bit of progress is to get the 2nd bearing halfs' soldered together, cleaned up enough to get back in the housing to check the fit and get setup on the mill for drilling and milling the hole to 8mm - ready to go onto the lathe..

Photo -

The setup ready to drill and mill the bearing to 8mm. Not tightened down yet so the table is not left under torque until I can do it...

The photo's not very clear but the bearing is in a kind of cradle of parallel's which I hope will help support the solder joint when drilling, and stop things moving around - all really because my current vice not good enough to use for this..

and my centre finder to line the mill up..

Regards

Allan.

You have got me trying to remember how I did my two Stuart #1s now. I don't really remember, but I would be very wary about relying on solder joints while machining, even if the chuck is supporting the job together.

I can tell you what I did with my Stuart triple. With this one, it is not practical to drill the full length of the bed and line bore. While you can easily make an extended drill when needed, it would be sure to wander. So the bearings are done in a jig. This is a seat for one bearing top and bottom half to fit into, complete with a couple of little studs to clamp them together just as they would be in the finished job. This is set up in the lathe in the four jaw chuck so that the desired bearing centre line is on the centre of the lathe. If the bearings don't already have a hole in them, you can do this with a wobbler. Once it is set up, you can bore all the bearings in turn, two for a #1 and 4 for the triple. The bearing parts should be marked to stay together and also to make sure that they all remain in same relationship. This is so that if there is any error they will all be out in the same direction. Now, since the seats for the bearings in the baseplate should all have been machined at the same setting, when we put the bearings in place they should all line up. This worked well enough for my triple.

Assuming the existing pieces were held like this in a jig, it would be no problem to clean out the existing holes with a slot drill. A normal twist drill should not be used, since it will try to align itself to the existing holes halves, which would tend to break the drill or at best make it wander. Once the holes are cleaned up it would be no problem to bore them normally. Although in many cases it is best to make the hole first and then make the thing that goes in it to fit, this is not necessarily the case with crankshafts where it is quite often better to get the crankshaft made with a nice finish first, then make a bearing to fit.

So anyway, you don't need to write off those bearings yet.

John

There are pros and cons. The main con is that everything costs more, the bigger castings are into the hundreds of pounds. A big pro is that I can see what I'm doing; makes a change from the electronics in the day job. Electronic components are getting ever smaller. I got an email flyer the other day for a simple logic IC, if I remember correctly it was 0.8mm square, and they got five connections in that space. No leads of course, they're a bit old fashioned these days.

Andrew

Hi John

That's an interesting post and some really good tips in there, thanks. So far if there's been a choice (and so far I've been lucky that there has been) I've been avoiding making tools and jigs - to be able to put all the time I have directly into working on the engine(s). Time I hope will get easier over the next couple of years as other commitments drop away to then be able to consider such things more..... But I'm taking on board and very grateful for all of the advice I can get for the future...

Hi Andrew

Yes, it's easy looking in from afar to forget the 'upscale' in expense as well..! I have it in mind though that longterm that is exactly what I'm working towards...

I've been having a great and interesting but eventful time drilling / milling the bearings this morning - post up later...

Cheers.

Allan.

Edited By Allan. on 11/05/2014 13:14:43

My bearings turning into a bit of a saga I think. Hope not everyone has given up on me yet though and some still finding it as interesting as I do...

This morning I made a start on the bore for the second bearing, intending to go to 10mm (not 8mm as previously said) ready to go on the lathe... After putting a 10mm Slot mill through the 'bad' bearing to sort out the wonky hole they should then be pretty close for further work..

The first slot mill about to be put through - 8mm

All going well with the slot mill, nice and smooth, no 'grabbing' of the work then progress stopped. I couldn't understand it for a while - then I realised that the Slot Mill had a 'shoulder' on it and I had reached it's maximum depth. None of my other Slot Mills have a shoulder - just this one! Unlucky again or just stupid for not noticing - don't answer that! Anyway my next Slot Mill size is 10mm (no shoulder) so off I go with that one, and again all going well until i come to the bottom of the hole and about to break through. As I hadn't reached the bottom with the last Mill it was now asking too much of the Mill and it stopped dead - and would not restart. I was glad I had used all the clamps and 'cradle' or I'm sure I would be redoing the bearing at this point otherwise... In all the work I have done with the mill to date I have never even seen it slow down let alone stop dead. I feel justified and glad of being so wary of the Gunmetal now and in taking all the precautions. Its tricky stuff if not used to it I think - drilling steel is a doddle by comparison!

Photo of the 8mm Slot Mill with the shoulder - and another, as per all my others, with no shoulder. I'll be checking for this sort of thing in future!

Luckily its just a blown fuse. The one blown is 6A, the Mill came with two spare fuses both 10A. Fitted one of those, best get another 6A to go back in I think. The Mill was fine again then.

The end results though are not too bad. This is one side of the 'second' bearing at 10mm bore. Needs cleaning up lots more, but has yet to be de-soldered again of course so I haven't been too fussy yet...

This side 2 of the 'second' bearing. Not quite aligned. Will definitely be trying Loctite next time for this kind of thing which should be much cleaner and hopefully much easier to align properly...

Test fitting the 'second' bearing in its housing. The alignment not too bad.

Next to drill and tap the stud holes for fixing and then onto the Lathe...

Regards

Allan.

Having seen your experiences, I think I would have fitted the unbored bearings and their caps to the baseplate, fixed the baseplate to the cross-slide, and drilled and reamed them in line on the lathe. I would definitely aim to finish ream them in position, as there is no facility for re-aligning them on assembly.

Neil

Hi Neil

Thats interesting, I had been thinking about if I needed to keep them permanently assembled after final reaming / boring i.e. once they are in the housings and finished they need to stay there to keep the alignment - I wasn't sure but think you have confirmed, thanks...

I'm thinking now to drill and ream to finish rather than bore... Then do the crankshaft to fit..

I've not done much with reamers so plan to ask some advice on how close to final diameter to use and what speed etc when the time comes..

Cheers.

Allan.

Allan: I'm still with you, this is one of the few threads I read regularly.

Hmmmm, where did you get the slot drills? I ask because the ground end doesn't look like right. The end of a slot drill should look like this, no 'bridge' in the middle:

As for reamers, here are a few notes:

1. Use a machine reamer, which cuts on the end, rather than a hand reamer which has a shallow taper on the flutes

2. Ideally make sure that the reamer is long enough to go through both bearings at the same time.

3. A general rule of thumb for reamers is half the speed and twice the feedrate of an equivalent twist drill

4. Leave enough metal for the reamer to cut properly; if I recall correctly the bore needs to be 1/2", so I'd drill, or bore, 31/64"

Regards,

Andrew

I'd still be tempted to make the crank first then if you don't get it spot on 0.500" you can bore +/_ to suit, if you ream it 1/2" and the crank comes out at 0.498" you are badgered to coil a frase. You could even bore each bearing slightly differently if need be.

For a similar reason I would not use a jig to bore the separate bearings, no disrespect to Allan but if the pockets or bearings are a bit different using the jig won't make them line up when in place. Thats why I suggest to bore to suit the crank with the bearings in place.

J