Boxford back from the dead

[AdeV]

Just a brief update tonight: Having now taken delivery of a second small pin spanner - I'd bought a small and a medium, but the pin on the medium didn't come close to fitting in the holes - I went to take the spindle lock nut off. And the small pins didn't really fit in the holes either  Must be metric pin spanners (4mm pin) and imperial holes (0.150" or thereabouts). That's about 3.75mm... Damn! However, I could get just enough purchase to unstick the two nuts from each other, thank goodness. The spindle then popped right out without any drama at all.

Pic 53 shows the various parts, pic 54 the now empty and more-or-less clean headstock.

The front bearing looks perfect, even the cup is clean and so smooth the camera couldn't auto-focus on it (pic 55). The rear bearing, however, is a different story - pic 56 & 57. You can see it's had some kind of a bash - indeed, all the rollers fell out when I tried to clean the grease off it. I was lucky not to lose one down the plughole of the sink  So I'll need to replace the rear bearing, and since I may as well do the outer cup as well, I need to figure out how to remove that. I believe it's a very light press fit, but I need to go read up on it before I tackle that. Also I need to find out what bearing it is, of course! The lathes.co.uk website suggested a fancy Timken bearing, but this one has no discernible maker's marks on it. I guess Boxford bearings aren't hard to find, and I believe they used the same size for every 4 1/2" lathe from start to finish. Everything else looks pretty OK. The pulleys need a good clean up, and the spindle has some rust internally which is a bit tedious - I might try some of this rust removing liquid you can buy (MC51), which various Youtubers use in their restorations & seems to do a spectacular job.

So that's it for tonight. Pretty much the last bit to take apart is the saddle/slides; then I can start looking at sourcing/making the few replacement bits I need to do, start welding the foot, and that motor/pulley plate. Hopefully the leadscrew, handwheels and various other bits will be done pickling by the weekend, and I can give them a clean up & check for excessive wear.

Thanks for following along - and all comments (even ones questioning my sanity  ), suggestions and hints/tips gratefully received!

[Sea.dog]

I seem to be having trouble posting some info on here, it doesn't seem to want to accept my attachments.

The outer race is removed from inside the casting. There are two small diametrically opposed holes that you can put a pin punch through to remove the outer race . I'll let you have the bearing details later.

[AdeV]

Hi Seadog,

I found a really helpful post on www.model-engineer.co.uk, which also mentions the pin punch holes, thanks! It also gave me the bearing codes - weirdly the back one is a metric bearing, the front one imperial... which seems odd... but it means I can get an SKF bearing for about a tenner. So that's nice.

[AdeV]

I had a bit of a rest yesterday, on account I've knackered my knee, but since resting it hasn't made the blindest bit of difference, I may as well press on regardless. 

Anyway, so I decided to measure up the apron handwheel pinion yesterday, as I'll have to make a new one. Or buy one, but they're £silly money, and it's not like I haven't got the machinery to do the job... the only thing I might need to do is buy an appropriate involute cutter (or make a hob... hmmm...  ).

Given that this is a 1948 machine, long before the European Union was invented, and not long after the French discovered the Metric system, I figured this was *bound* to be an imperial gear - doubly so because this is a copy of an American lathe, and they've yet to discover Metric even now... so out comes the calipers. 0.810" ish OD (bear in mind, this has some wear on it), RD is about 0.570" (IIRC - I'm on a train and don't have my notes with me), and has 14 teeth. But.... none of the imperial sizes really come close. At 19.5 DP the OD is too small, and at 20.0DP the RD is too big...

So, with some trepidation, I switched my computer over to French..... and sure enough, it appears to be a 1.25 modulus metric gear! 

So, before I rush out and buy a $5 Chinese-made mod 1.25 cutter of the appropriate number - does that seem likely? I can't imagine I have one of those already, given all my involute gear cutters have come from auctions of "random stuff" over the years.

I figured if I measured the spur gear that the pinion drove (which also appears a lot less worn) I'd have my answer, but I remember now it's lurking at the bottom of a barrel of citric acid, hopefully getting shiny, clean and lemon fresh. 

Anyway, that's todays question for any Boxford experts (Seadog  ).

[Pete.]

It will be 20DP. There's an adjustment for small tooth count pinions in fact I just recently made a handwheel pinion for someone which was 14DP but worked out 13.something. Let me find the details....

[Sea.dog]

20DP sounds right to me. Pete is spot on.

[AdeV]

Got to agree with both of you - the big cog it drives (which I rescued from the parts washer, having accidentally left it soaking for 4 days  ) comes out at almost exactly 20dp when measured, close enough I can touch it.

So - 20dp it is! I shall look to see if I already have a suitable cutter - if not, RDG sell them 

Nothing much else to report tonight, my MC51 rust remover arrived, so I tried a couple of rusty bits out in it - wow... that stuff *works*. I'll do some photos of that, possibly on another thread.

[Pete.]

I can cut you a 20DP pinion if you don't have a cutter mate.

[AdeV]

Hi Pete,

That is a very kind offer, thank you! If I can't lay my hands on one, I'll turn up the blank & send it over to you, if that's OK.

I may also have a go at making a gear hob, in the style of the old (and now removed) Hobbynut videos on YouTube. I think someone else has done a similar video or series since, if not, and it works, I might do one myself as well. It only produced an approximate involute, but the nice thing was, one hob was good for anything from a rack upwards. It wasn't a true hob... but a sort of multi-tooth form cutter.

Anyway, more of that later, the kettle's just boiled so it's time to go warm up my parts washer liquid & get on with some scrubbing!

[chipenter]

I looked at my lathe and the Boxford handwheel pinion is smaller and cross drilled for a taper pin . I would have to sleeve it , it's scuffed ware the handwheel has slipped, one patch of rust but the rest is good yours for a nominal fee .

[AdeV]

Thanks for the offer Jeff. At this point, I'm still thinking of making a new one from blank. Although I don't have a 20DP cutter (I've got a 12DP and a 40DP, don't think I'll get away with splitting the difference  ), but I've still got the Edgwick, and Pete's kindly offered to cut the pinion.

As for everything else - bit of a quiet weekend. I've managed to damage my anterior cruciate ligament in my right knee, so walking around is a bit of a faff right now. I assume it's named "cruciate" because when you damage it, it's "ex-cruciate-ing"? 

Also, I found I was clean out of TIG tungstens suitable for Aluminium welding (I've only got some ancient Thoriated ones left - mmm, radioactivity, tingly on the tongue), and Amazon were a bit tardy with their Sunday delivery, so I only just got the new gas lenses and tungstens that I ordered. Also, controlling the speed of the burr in the die grinder is a right royal pain, trying to spin it at a slow enough rate on the trigger to cut a reasonable amount of metal proving to be impossible whilst also keeping it on target. I used to have a regulator valve, but it's buried somewhere in the stuff I still haven't gone through since moving into the new place.... easier to buy a new one Apparently, it's a voltage regulator too  I think the Chinese translator's had a glass or five of wine*...

Lastly... somewhat serendipitously, I was watching a video ("Trev's Blog") on the InterToobs the other day, about de-rusting. Wondering what his "magic solution" was.... turns out, weak citric acid! Unlike me, though, he warmed his in a bucket using an aquarium heater, and added a dash of fairy liquid (liquid dish detergent/soap for those not of a British persuasion). Next day, I get a call out of the blue from Dad, his missus has just liberated three large tea urns from her workplace. Two were spoken for, would I like the third? Damn right I would!    A perfect heated de-rusting vessel  Obviously, in its current stance, it's not a "switch on and forget" device, as it'll boil the acid, and I'm not sure that's wise - so a bit of  to come - an Arduino attached to a temperature sensor and a relay should allow me to vary the temperature between ambient and very nearly boiling with consumate ease. Also, once I've finished de-rusting, I can throw a few teabags in there and have lemon tea 

Next jobs, then: The welding will now have to wait until the weekend, most likely. I need to get some suitable diameter steel - everything I have is either too big or too hard (said the bishop to the actress) or too short (retorted the actress). There's still some parts cleaning to be finished off, I'm waiting on the rear bearing to arrive; I'll pop the cup out in the next day or so. I also need a supply of paint stripper, some paint, and I want to reproduce the old Boxford plate, the speeds/feeds plate, and the the threading chart, but with a twist (I'll keep the originals for posterity). Oh... and I've decided sod it - I'm going with the black & gold paint job. If the next owner after me wants it to look exactly like it left the Boxford factory, in late Spring/early Summer 1948... they can jolly well repaint it themselves 

Thanks, by the way, to everyone who's contributed so far with suggestions, helpful information, offers of parts etc. I'm very grateful and humbled.

Oh.... I also got a shiny set of collets + drawbar from fleaBay the other day, so I look forward to fitting that! It's in close to pristine condition, looks like it just needs a dot of lube or two to help the collets slip in and out, but is otherwise pin on! I'll take some photos of that when the lathe is back together.

Meanwhile, here's some piccies of today's Amazon haul, and my new deruster.




--

* Chinese wine... is about 40-60% alcohol, and drunk in much the same manner as Tequila. It's very scary stuff, I might try using some as paint stripper...

[tom osselton]

“ I've managed to damage my anterior cruciate ligament in my right knee “
I did that back in 92 mind you I snapped mine while launching myself off a 6 foot fence! It seems like I forgot how to tuck and roll! It was fixed by way of reconstructive surgery.

[AdeV]

Tonight's instalment isn't really specific to the lathe.... but about derusting in general.

First - here's a link to the video I mentioned about derusting parts. The link will take you straight to the part where he's making his solution: https://youtu.be/fdTqrgq_5ag?t=214

If you're not fussed to watch - it's basically 10 grams of citric acid granules (from a well known auction site) per litre of warm water in a bucket, with a dash of washing up liquid to act as a wetting agent. He uses an aquarium heater to maintain temperature - I use a stainless steel tea urn. What the acid will do to that long term, I'm not sure... I'm sure it can't be good.

Anyway... Pictures 1-4 show a rusty chuck which came with the lathe, and picture 5 is a re-cap of what the pulleys looked like inside the headstock (although they seemed less rusty once out in daylight... not sure if that's just an artifact of the camera flash or what.

I used about 6 litres of water (about a gallon and a half in US measures), and therefore 60 grams (2oz) of citric, and just to be contrary, an Imperial Squirt (about half a metric dollop) of washing up liquid. I warmed it to around 40 degrees C (that's about degrees 40 in French measures), and added the pulleys and the chuck. After about an hour I went back to it, re-warmed it to 40 (it was only 5 degrees down from where I started it, which is quite remarkable given the complete lack of insulation on the urn), and left it overnight. In the morning, before going to work, I gave it another dose of warmth and a quick stir... then returned to it when I got home about 12 hours later. So all in, it had about 24 hours +/- in the acid, of which maybe 6 hours were above ambient.

The results are remarkable... pic 5 is what I saw when I opened the lid  , pics 6-8 show the state of the chuck & pulleys after a quick wipe down with a rag. A remarkable transformation for such cheap ingredients! I'll definitely be looking at automating the urn so it maintains around 30-40C. It's also a lot cheaper and quicker than mixing up a massive barrel of freezing cold acid (with water straight from the glacier). Mind you, I still can't fit that leadscrew in it...

The chuck has gone back in for another night, as there's still a few spots of rust on it. Hmm, just need to find/fabricate a chuck key so I can see if it actually works! There's plenty more ancillaries to de-rust, but the cast iron bed I'll use that MC51 on a rag, it also won't fit in the urn!

That's it for now... got to rest this damn knee.

[awemawson]

Ade when I use citric acid for long shafts I use a suitable length of either 110 or 150 mm underground drainage pipe stood upright and a blanking plug on the lower end.

I have a couple of such lengths and I also use them for nickel plating (after a good wash!)

[Will_D]

Ade, stainless steel loves an acid.

It helps build up the Chromium Oxide layer which protects the steel.
Often after fabrication, stainless parts/installations are "passivated" by use of acid washes/soaks.

Stainless does not like stong alkaline solutions. We use this to clean home brew equipment and you dont want to leave in for more than 24 hours.

HTH

Will

[AdeV]

Andrew - I like it, great idea... I could stand it in the urn turned up to 11 to get it all nice and warm too!

Will - good to know, thanks! I was a bit concerned it might eat the metal eventually... but if it makes it better, wow! Cool 

After a quick trip to the quack, it seems my lower leg isn't about to fall off, so with a bit of luck I'll be bouncing around like Tigger* again soon.



* An old, slightly crippled version of Tigger...!

[philf]

So - 20dp it is! I shall look to see if I already have a suitable cutter - if not, RDG sell them .....

Ade, don't forget the pressure angle. 14 1/2 or 20 degrees.

[Pete.]

Boxford is usually 14.5, Denford is 20.

[philf]

Ade, stainless steel loves an acid.

It doesn't like hydrochloric!

[AdeV]

Phil - good catch on the pressure angle. This leads to a conundrum....

Please see pictures Exhibits "A" and "B": Exhibit "A" is the sliding pulley which either engages directly with the pulleys via drive pins; or engages with the backgear shaft. Exhibit "B" is the backgear shaft. For ease of viewing, I've blown up the relevant parts of each picture. Note that the main gear has "14 PA" stamped on it (the "4" looks more like a "+", I guess it was the apprentice's day on the punches). The backgear shaft, on the other hand, has "20PA" stamped into it!

Now - this IS possibly correct, as the large gear on the backgear shaft is, in fact, a pinned press fit, whereas the small gear is cut into the shaft itself. Either that, or one (or both!) of the gears have been replaced at some point, with the wrong item, perhaps a gear off a later Boxford. We shall never know.

Is there any obvious way to check the pressure angles? The teeth all seem to mesh OK, but I don't really know what I'm looking for.

In other news, I popped the back bearing cup out using a small pin punch and a handy lathe part to tap it with (the hammer wouldn't fit!) As anticipated, almost no force needed, just a few gentle nudges on each side in turn and out she popped.  There's no makers mark on the backside, but rather fascinatingly it's had the words SCOTLAND "CARRICK" (in quotes) and a number hand engraved on it. The number is very hard to make out, but after some googling, must be 14274. Looking closely at the front of the bearing again, it also has SCOTLAND and CARRICK (no quotes around it, this time), and a number, but the number's more worn than on the back. Although I can't read it, some googling and searching eBay suggests it must be 14137A, as that pair make up a bearing the exact size of the one I've got (as measured with calipers, so +/- a couple of thou). If anyone can explain, though, why Scotland and Carrick appear to be hand scratched into the bearing, please share!

So... the website I linked to earlier in this thread, with the bearing sizes in it, has led me astray  The rear bearing I have on order has a cup size some 3mm too big; therefore, tomorrow, I will order the correct bearing. If anyone needs the wrong bearing for a Boxford spindle, drop me a line, it's yours for the cost of postage!  (and if it happens to be the right one for your lathe - well, bouquets all round 

[awemawson]

You can visually determine whether the pa is 20 or 14.5 by my crude but effective method:

Roll the gear in Plasticine to create the correct meshing rack. Cut longitudinally with a sharp razor blade and look in profile at the flank of the rack teeth which for an involute gear should be a straight line. This flank angle IS the pressure angle. The difference between 14.5 and 20 degrees can easily be determined with a cheap school plastic protractor.

[AdeV]

That's not that crude, and sounds effective! If you'd called it "modelling clay" it would seem positively professional!

Looks like there's some Plasticine on my shopping list now!

[Sea.dog]

It definitely looks to be 14294, doesn't it? I've asked for any info on these gears on one of the Boxford forums. I'll let you know if there's a reply.

BTW, the large gear is called the Bull gear.

[Sea.dog]

Pretty much as expected, the backgear is from a later machine. The PA was changed in the '50s so the 14 is a pretty rare animal. Broken teeth are quite common when chucks get jammed. Since there's no way of locking the spindle until we get to the MKII the usual method is to engage backgear as a lock. Bull gears do come up for sale from time to time and the chap I spoke to does have a set available.

[AdeV]

Thanks again for the info - I’m wondering now if the pulley set is original or not - as it is in mesh with the small gear, which is 20pa. It’s possible that the driven gear on the back gear shaft is the original 14pa, as it is pinned to the stamped shaft. Looks more and more like I need to go buy some plasticine at lunchtime