SHED MATTERS 2

[micktoon]

Hi Stanley , you seem to be making steady progress and your 'new' eyes seem to have the welding sorted out too now Its taking shape nicely and will look smart when done, the HM is a good bit of kit too
Cheers Mick

[Stanley]

I think that if I did some practising and got myself a modern shield that automatically changes to dark filter I could do a fair job now. One thing is certain, the big oil cooled welder was a good investment, very steady output.
The HM is like me, slow and steady but it does a good job. That key way cutting was hairy, it's got to have a full cut on the first pass, but if you go slowly it does a good job. That's a big cut for my El Cheapo Taiwan VM! But you can see from the chips, the cutter never warmed up, they came off bright and shiny.
I'm glad that stage is over without disasters but when I looked at the tee slot it could do with one more light cut on the last side I cut, no problem because it is only a skim.... Might as well have it perfect! My problem is that I watch these Bridgeports etc. with DRO on Youtube and go green with envy. I'm sure some of the lads have a good laugh when they see my timid cuts....

[Stanley]

I was late getting into the shed this morning, too many small matters needed attending to. That's one of the disadvantages of being a singleton, you have to manage your own life! First job when I did get in was to measure the slot I cut yesterday and take one light cut to match both sides up.



Once that was done, a bit of measuring up and then I drew the crosshead I wanted. I can get it out of a piece of 1" square bar, the problem then was finding it! However, after a good root and ignoring the bits that would do but needed a lot of reducing, I found this, a nice little piece of 1" square bar.



Then into the HM after changing the cutter and saw it off at 2".



That's better, the minimum of machining needed and no material wasted.



Then into the VM, get it square and start reducing it to exactly what I want. Knocking off time but a clean start for tomorrow. Steady progress, no rush and no mistakes!

[Stanley]

The design committee are worried that I might not have left enough meat in the head of the crosshead but I think it's going to be OK....

[Stanley]

I was late in the shed but straight into continuing with the crosshead. I needed one dimension to be exactly the width of the slot in the guide with a bit of clearance.... Once I had that correct I wanted to square the ends. I swapped this 3/4" cutter for another that I haven't used as much so it had enough depth to face the ends in one pass.



I allowed myself to be distracted. I use this brass bar as a parallel and it's about a thou out of truth so I gave it four new surfaces.... Never time wasted!



My next job was to reduce the head of the crosshead to 1/2". As soon as I started I realised that the new cutter I had put in was OK for brass but not cutting this steel properly. I considered putting another one in but then decided to have a fresh start with this cutter, back it off and sharpen it properly. That did the trick, it's OK now. Knocking off time, not a lot done but once again, no mistakes. Tomorrow is another day in the shed!

[Stanley]

I started the day with what may look like a distraction. I have been annoyed for a while by a chatter in this handle. I thought it was inside the handle and started this morning by addressing that but found it made no difference, the chatter was in the cross feed spindle so I took it to bits. I identified the reason as too much end float between the bearing and the handle assembly so I found a very thin brass washer and took the play up with that. The first one was too thick and made turning the handle very hard so I pulled it to bits again and found a thinner brass washer. I got it right the second time, still more resistance than there was in the turning motion but supportable and it will bed in with use. On with the crosshead reduction!



I then made a surprising discovery, have a look at the 1/4" cut I have on the cutter here. I've never managed to take that much before! I still can't see why eliminating the end float has made such a difference, something to do with harmonics I suspect but the fact is that my El Cheapo VM is performing much better!



Twenty minutes later and the meat is off the crosshead. I didn't attempt any more 1/4" cuts.... but I took much bigger cuts than usual and speeded the job up no end.



I spent about half an hour with my big flat file taking the milling marks out of the crosshead and making it look beautiful.



Here's the end result, looking tidy, sliding nicely in the tee slot and marked with a register so I can keep it the same way round.



The next move was some very careful measuring and thought to ascertain the position the cross slide needs to be in on the bed to give me my two inch stroke. Then mark the bed so I can position it easily again. Then two 1/4" holes drilled in the base of the slide for the cap screws which will hold it in place. I didn't counterbore for the heads yet....



Because I wanted the full drilling to ensure the greatest accuracy when I used the transfer punch to mark the positions of the holes in the bed that will have to be tapped for the screws. I clamped the slide to make sure it didn't move!



It was knocking off time but I wanted to centre drill this hole while I remembered which punch mark it was. I had another mark in almost the same location that I had put there when I was finding the centre. This'll do for today, I know exactly where I am. A mixed morning but more progress and no mistakes. And the odd discovery on the way!

[Stanley]

That improvement in cutting after eliminating the end float in the feed screw intrigued me and overnight the Advisory Committee have come up with what I think is a plausible explanation. Being an El Cheapo, the Taiwanese VM doesn't have any adjustment for end float in the spindle assembly, the location is fixed by a spring loaded dowel pin driven through the handle assembly and the shaft so the only way to get rid of the float was the brass washer.
End float on the cross drive of a lathe is no problem, we all know that, as long as the play is taken up before starting the cut all is well. The difference with milling seems to me to be the fact that we are dealing with an intermittent cut and we all know how damaging 'climb milling' can be. I think that what is going on here is the fact that being an intermittent cut, any play in the feed screw allows the drive train to continually recoil and then recover. Only a tiny amount but it introduces a harmonic in the cutting which in effect means that every time the next tooth arrives in the cut it 'bites' as the pressure of the cut comes on after the recoil. The deeper the cut, the worse the effect. By minimising the end play I have cut this effect down and that's why the cutter is performing better. I don't think this is as bad on the long feed of the bed because the gibs are so much longer and have more resistance to the initial recoil if there is too much end play.
Interesting, and I'll experiment further as I use the mill.....

[Stanley]

Usual drill to tap the two 1/4"Whit holes in the bed, centre, drill and tap all on the same setting to make sure the holes are accurate and truly vertical. Then counterbore the holes in the slide to take the heads of the cap screws.



I got the centres right, the slide pulled down onto the bed dead straight and in line with the centre.



I bolted the cylinder on the target plate with two bolts to make sure it was firmly in place and then marked on the crosshead where the piston rod centre is. I did it by putting some blue tack on the crosshead and letting the end of the rod mark it. Then a good pop mark in the centre of the impression. Nice thing is that the pop mark is dead centre on the crosshead.



Amazing how much tackle you need to drill and tap a 5/16" hole! Thank god I spent the money when I could!



Notice the sophisticated depth gauge on the drill, insulting tape. Cheap and dead accurate, don't knock it!



A trial fit and the rod is dead in line and starts to screw in easily. I didn't go any further than this because we haven't finished with the crosshead yet.



The 1/4" hole for the clevis pin that will locate the con rod drilled and the burrs taken off it.



The focus shifts now to the flywheel end of the bed. The con rod will be almost the last thing to be made because I won't know the exact centres until the crank is made and mounted in its bearings.... So a bit of decision making and altering of plans.



Once I had the measurements I had to find some stock. This will make two pedestals but a bit shy of what I wanted. No matter, I can work round that. Notice that I had to support the end of the stock because I hardly had any hold on it in the vise on Mrs McMaster.



The setup worked OK. I have my stock ready for tomorrow.
Nice morning, lots done actually!

[Stanley]

Today's job is to get the pedestal blocks clean, square and matched. Notice that one of them has a flaw where the cut was started to burn this off at some time. I shall work round this, I need all the meat I can get!



I've got them square (note the flaw) and have them marked for overall length, 2 1/4". I shall cut the meat off with the saw in the HM.



No dramas, they are ready for final milling.



The cutter has done a lot of work so I dressed the wheel on the T&C grinder, backed the cutter off because that was where it was set from the last time (16 degrees). Reset it to 5 degrees and made as good a job as I could of resharpening. Never time wasted....



The best way to ensure a perfect match is to machine the blocks together.



The final result. Note the good finish from the cutter and the fact that I have kept the flaw away from the very end of the block where it would be much more obvious. Two identical pedestal blocks and very close to the size I was aiming for. There has been no waste!



Knocking off time. First thing tomorrow is some decisions and then some measuring and marking.

[Stanley]

The target is the pedestals... The first thing was some measuring and decisions. I had to finalise the design of the crankshaft and having decided on a shaft diameter in the bearing of 1" I had to make sure I had room for the bushes and at the same time got the shaft height as close to the piston rod centre as possible. A horizontal engine looks wrong if it's kicking uphill. When I had decided this I translated it to the pedestal and did some marking. I found I could afford to reduce the height a bit.....



I put both blocks in the vice and reduced them to the same height. The cutter was working beautifully, nice finish. Time spent sharpening it was well spent.



Once I had the height right I did some more marking for the holding down bolts, the lubricator and the 1 1/4" bore for the bush. Then some careful drilling! Actually it was at this point I had to break off to deal with a pressing matter so in the end I didn't get as much done as I was aiming for.



Never mind, I had a straight edge at knocking off time and as far as I can see, no mistakes.....

[Stanley]

The first job was to cut the excess off the 1/42Whit set screws that locate the raising blocks and file the base of the bed dead flat. We want these blocks mounted solid in their working position.



Clamp the pedestal in exactly its right position (after checking your register marks!) and transfer punch the locations on the raising block.



Drill and tap the holes under the pillar drill to get them dead on target and properly upright.



The pedestals in their correct positions and bolted down.



The two jaw brass chuck comes in handy again. Easy to centre using the tailstock.





Took the meat out with a 1" drill and then bored it to exactly 1.25".



A standard 1.25" plug confirms it is exactly right for the bush.



Not a bad morning's work. One pedestal ready for it's bush. I know exactly what I am doing tomorrow....

[Stanley]

I started the day by boring the other pedestal for the flywheel shaft bush.



Once I had both pedestals bored I took advantage of the fact that I had the 2 jaw i9n the lathe and took a light cut across all the faces of both of them. I shall paint the raising blocks but leave the pedestals a natural finish so I want them to look nice....



When I had them tidy I broke all the edges with the fine diamond hone you can see on the bench (red handle). You can get these in sets of three and they are very long lasting and useful. You get a fine, a medium and a coarse.



It was clocking off time so I tidied up and gave the lathe a good clean. We will be making a lot more swarf shortly!

[Stanley]

The first job this morning was to put all the set screws in the front end of the cylinder and tighten them up. Then take the lid off the back to get at the nut on the piston rod because we shall be tightening the rod into the crosshead using this and of course tightening its grip on the piston as well. While the end is off the cylinder I want to drill and tap the top of the cylinder 1/4" 26tpi for the lubricator. The vise on the pillar drill is one of the best things I ever bought, it never lets me down!



A little tip here, pure Newton Pickles. Put some grease on to a suitable carrier and insert it into the cylinder bore before you start drilling and tapping. This will catch all the swarf and hold it. Newton used to do this inside the ports of a full size cylinder when he was boring it so that he caught all the muck before it started to wander off where it was not needed.



Tightening the rod in the cross head and at the same time locking the piston on the other end of the rod. Dead easy and you can get both really tight.



That's it for this part of the build, now we need to start thinking about the crankshaft. I started by checking all my measurements and making sure I had them right.



I put my most accurate chuck on the lathe, the big four jaw. Then I spent as much time as I needed to get the blank central in the chuck and running true out at the other end. I got it to within a thou which for an unfinished piece of stock is fine.



Put a good big centre hole in the end and then turn the face parallel. Once you have done this, reverse the stock in the chuck and do exactly the same to the other end.



Close of play. I have the stock centred and faced at both ends. That's a good start and I'm ready for tomorrow.
If you look at the instructions for building engines most versions will recommend a built up crankshaft when you get to this size. If you want to do it that way, go ahead but I always chop them out of the solid. This means an amazing amount of swarf, about 80% of the present weight but done properly it makes the best job. One more thing, the classic way of turning a crankshaft is between centres but I'd rather do it with one end firmly in the four jaw chuck. Plenty accurate enough if you clock it when installing it and you are absolutely sure of your hold when you eventually have to do an interrupted cut on the crank pins.

[Stanley]

It's a while since I made a crankshaft so I was reviewing what I was going to do. Normally I use the oil feed to flood the cut but I use neat oil and I always finish up with a shed full of smoke to I think I'll cut it dry..... Also been thinking about the shape of the cutter, I break some of the rules when I am doing this. More later.......

[micktoon]

Hi Stanley, its looking really good now, nice work and explained well as usual. I am looking forward to the next bit I always like seeing the crank being chopped out of the solid.
Keep up the good work Mick
P.S the treasure chest never fails to amaze me

[Stanley]

Thanks Mick. You'll enjoy this morning then!



I cleaned the billet and gave it a coat of marking ink, then I put a few key locations on it. I need to know where I am cutting to even though this is only rough cutting.



Away we go! Sharp cutter and a dry cut that is just trying to turn straw coloured as it comes off.



Later after a lot of swarf, we are making progress. No point rushing, quietly away and make no mistakes!



Knocking off time. I have had a bit of a clean up. Notice that while I am cutting I have the swarf bin inside so I can keep putting the thick of the swarf straight into it. Not a bad morning.... More of the same tomorrow!

[Stanley]

When Brown's and Johnny Pickles made big three throw boiler feed pumps they first used forgings to make the three crank shaft but after a couple of failures they went on to chopping them out of an 8" billet of 90 ton steel. Jim Fort remembered turning them and he told me it took at least six working days to make one but they did the job, they never had a failure.



A new pump in Henry Brown and Sons shop.

[Stanley]

First thing is to check the setup, remember the stock got hot yesterday and we don't want any surprises.



We are rough cutting so your best friend is the spring callipers. All to easy to take too much off when you are in the swing!



All ready, off we go. Still cutting dry and the cutter is holding up well.



I soon had it down to under an inch and a quarter. I re-sharpened the cutter ready for the next session and made sure it was set on centre.



I'm going to have to take the stock out of the lathe and it will be going back in the same place so it makes sense to mark the stock and the chuck so you can get it back in and centred as easily as possible.



Before I go any further I have to mark the centres for the crank pin, one inch offset from the dead centre.



Once I had popped the locations I had to drill two hol;es with the centre drill so I got the electric drill out, it's the easiest way.



Both ends done....



The next job, and it was Newton that taught me this, is to get the meat out of the crank webs on the milling machine, far easier than a long series of interrupted cuts. I want an inch square block left and so a bit of careful measuring and marking is indicated!



I need to finish up with a 5/8" gap between the webs so I found a 9/16" cutter long enough and gave it a complete resharpen including backing it off.



All set up and ready to go. Dead easy to be sure it is square, the tee slot in the bed makes sure of that!



Clocking off time. Getting on well with the cutting. The cutter is working fine, I think I am getting close to cracking sharpening milling cutters, however, you'll see from the small shiny chips I am not pushing things. As you get older you get more patient! I know exactly where I am starting tomorrow. Nice morning's work.....

[Stanley]

I couldn't resist logging in just to look at that cut! I've got the end mill just about right and I'm sure I could push it and take stronger cuts but I have plenty of time.
I can't stress too much the value of taking that meat out of the crank before turning the crank pin. Remember that the interrupted cut you would have to do would be done with a slender cutter like a heavy parting tool hung out over 2" from the toolholder in order to clear the stock when it swung towards you. I've done it that way and I can tell you it's boring and miserable!
Another point to notice is the order in which I am cutting. I shall not go onto the crank pin when I've finished the milling but take out the meat for the 1" shaft next to the chuck. That way, and because I have the material held rock solid and centred in the chuck I can have as heavy cuts as I like with the minimum of pressure on the tailstock centre. If you think about it it's only there for insurance, you'd quite happily do this cut without a centre. There's a reason for this. A mistake I have made in the past is to have too much pressure on the centre and because you have taken all that metal out of the crank it can close up and bend as the stock heats up and expands. I've had to take them out and straighten them before now! Doing it this way means that the last cuts that have to be made are the light ones for the crank pin and all you need for that is light centre pressure. At one time I used to mill a block and put it in the gap so it couldn't close but this way is better.
Sorry about the bleeding obvious but it will be useful to some of the brothers......

[Stanley]

I started the morning by finishing the big cut off. I was a bit late getting in there this morning but didn't try to rush and 'catch up', I have nothing to catch up to!



I blued the bottom of the cut, did some measuring and marking, put a punch mark in for where I wanted to cut to and then set the stock up again under the mill. I'm using the square to make sure I have it vertical but it's not crucial as I have left some leeway to play with.



One side taken out. Reverse the stock and do the same again.



Nice! That's a lot of metal got rid off. All you do when making crankshafts this way is throw good metal away!



Back into the lathe. Match my marks up and quickly clock it in to within a thou. That'll do me.



I took one tidying up cut on the section I had already roughed out to check the cutter.



Then I tidied up the centre section and took the first cut on the section nearest the chuck. All set up for tomorrow....

[Stanley]

Straight into shifting metal. I put a sturdier cutter in so I could push it a bit. The tailstock centre is just engaged but no pressure and I kept checking it as the stock warmed up. Remember what I said about too much pressure distorting the webs....



A bit later..... I have got this section roughed out the same as the other end. The difference now is that I shall take this end down to finished sizes as when I turn the crank the stock will be reversed and the thicker roughed out section will be an adequate drive, stiff enough.



Kno0cking off time. The left hand end is finished. Tomorrow I shall reverse the stock, mount it on the centres for turning the crank and get that done. Once the crank is done I can finish the shaft which will be next to the chuck so stiff enough without any pressure on the centre.
In case you haven't noticed, you can see the crank appearing as if by magic!

[Stanley]

I did a last bit of titivating on the finished end of the shaft. Not entirely satisfied with the finish but they'll never see it off the Ribble....



I decided to turn the crank pin the old fashioned way, between centres, it's only a light cut so I'm pretty sure I can get away with it. I keep meaning to make a centre that fits the taper on the nose of the Harrison but have never got round to it so I chucked a piece of silver steel in the collet and turned it to 60 degrees. It will be dead accurate!



Then I hit a problem. I haven't got a dog big enough to go on the stock. I must have hit this problem before but I can't for the life of me remember what I did. So I left it alone for a while and made some vegetable soup!



I decided to do it this way. I drilled and tapped the end of the stock for a 1/4" whit set screw.



I think that'll do it! Thanks to John Mills for the tip about using plastic cable ties to anchor the dog! All we need now is a cutter.... [I swung it by hand and it's frightening to see the way it oscillates.... Just think what it would be like if we hadn't chopped that meat out with the miller!]



I couldn't find the cutter I have made before so I made a new one. The problem with cutting the pin is that you are constrained by the webs of the crank. It's almost like parting off with a 1/2" cutter with all the problems of chatter etc that would bring. I found a piece of 5/16" HSS and sharpened it just like a parting tool but put a nick in the centre so that it's two cutters in effect. I've done this before and found it works, you can traverse enough laterally to pick up the metal the nick has missed.
That's it for this morning, not a lot done but I have all my ducks in a row and no mistakes made! That means it's a good morning.

[Stanley]

I had to start this morning by undoing the last thing I did yesterday, mounting the stock between centres. I had forgotten to put the cutter into a block and adjust it for centre height.



That was soon done and I got set up again. Ready to start cutting. Set the speed to 34rpm, quite fast enough! And make sure the cross feed was in the right gear.



First cuts were to straighten the web up on each side. They were remarkably square, my set ups must have been good. You won't get a perfect finish but good enough.



After some very slow careful cutting I've got to the point where I am cutting the actual crank pin. Just think what would have had to be taken out if I hadn't milled that excess out! Well worth the time it took.



Some time later.... We have a crank pin, polished with two grades of emery as well! It is slightly over the .75" I was aiming at but it's a good finish and I'm glad to stop interrupted cutting! I can make the brass the right size for the bearing.....



The collet and gear taken off the lathe and put away. The 4 jaw bck on and get the stock mounted and clocked in. As it turned out I was wasting my time!



When I spun the stock I found that the section I am going to cut next to the chuck isn't running concentric so first thing tomorrow I'll dial the actual shaft in instead of the stock but that's for tomorrow, it was clocking off time.
If anyone thinks I have been over cautious and slow they are probably right but..... I've done what I set out to do with no cock-ups. Go and make a shaft for yourself and bugger it up at the last process and have to make it again. I guarantee you'll be even slower than me with the next one! Sometimes slow but sure is the best way.....

[Stanley]

I was late into the shed.... First job was to dial the shaft in. I have it running within a thou of truth, that'll do me. Bleeding obvious tip, don't expect total accuracy if the surface you are clocking isn't a mirror finish!



I'm not going to bore you with how I got here but here's the shaft finished except for tidying the ends up where I cut it off the end blocks. In case you're wondering why one end i9s 3/4" and the other 1/2" it's because the thicker end is for the flywheel and the other end is for the eccentric. If you have the shaft more than 1/2" you'll find you have trouble accommodating the throw on the eccentric.



I changed the 4 jaw for the 3 jaw SC. Ready for doing the shaft ends. But it was knocking off time so I cleaned the lathe up and called it a day.

[Stanley]

Couldn't resist going in to have a look at the shaft this morning. It's a chunky little bugger but it's OK.
I had a fall yesterday and at the moment I'm minded to keep out of the shed, I woke up an old war wound in my right arm as I saved myself. I'll take a view later but if I am AWOL that's the reason why. Nothing serious but an annoying and painful nuisance!