The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: RichardL on 02.11. 2008 18:14
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Hello All,
I bet this satisfies LJ's thirst for a new topic and discussion.
I think there might be interest in the Smiths Chonometric cleaning, service and repair I am underataking. I have done a fairly extensive web search and have found almost no photos (I think I found a total of 1) of the inside of a chronometric speedometer. If I am correct, with the addition of my photos, our forum will become a major source of photos for others who are looking.
Removing the bezel was the first challenge. One site said to put on a leather glove and twist off the bezel by hand. If no-go, apply thin oil. I let Liquid Wrench sit overnight and still had no luck by hand. Thus, you see my approach using two strap-wrenches, which did work.
The speedo was in much better condition than I hoped. The lubricant was sticky. I washed it out with ether starter fluid after wrapping the odometer and trip wheels in plastic food warp to avoid getting too much solvent action on the numbers, which are said to be quite sensitive to any solvent. In retrospect, I probabaly should have removed the clockworks from the frame to wash it out, but no harm was done. By the way, the speedometer truly is a clockworks, as it is designed to update speed readout every 3/4ths of a second. Recommended lubricants ranged from instrument oil to motor oil. I chose Marvel Mystery Oil as being something in-between and which I believe to be a high-quality thin motor lubricant; this I applied with a baby's medicine syringe.
After lubrication (and quickly to avoid oil overspray from acting like a solvent), I cleaned the the odometer and trip wheels with cotton-tipped swabs and soapy water; no solvents allowed.
The one thing that was broken was the tripmeter reset shaft. Reset shafts for magnetic replicas are available, but I could not find one for this old clock, and I didn't want to wait just to find out that I can't get one. (If someone knows where I could find one, please let me know). I fumbled around my tool box and came up with an awl that was just 0.025mm larger in diameter than the 3mm original shaft, so I have fashioned a new shaft from that, as seen in the photos. The little toothed wheel and shoulder behind it are both from the original part. removed by drilling, and now swaged onto the new shaft. The tapered arm (not custom made) seen extending out from the trip shaft lifts the pawl during the rewind process.
There will be more photos and talk as I move forward, so, for now, that's it. Some of the photos are pre-cleanup and some are after. If you can't tell which is which and need to know, let me know. Also, I'm not being very disciminating with the photos, so they will be in multiple posts and in no particular order.
Richard
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Here are more Smiths Chronometric photos.
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Interesting stuff. I tried to get the bezel off my speedo but gave up in the end and sent it to a specialist. I actually broke a strap wrench but it was probably an inferior quality tool. I then tried a length of leather belt wrapped round the bezel and used one of those oil filter removing wrenches that you use with a socket handle, the sort with pivoting arms. That was just distorting the speedo case so I decided I was doing more harm than good.
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If the strap wrenches had not workd, my next approach was going to be to rout out or turn a hardwood doughnut with the bezel profile on the inside, split that in half, then grab it with a strap wrench or other circumferencial tool, like your belt idea.
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Brave man Richard!
The speedo is a place where I have been in and come away in tears, not for me I'm afraid much too delicate. But you think your speedo bezel was difficult to get off, you should try a Military issue that has an anti tamper locking device rivet on the underside, this has to be carefully ground off before even attempting to remove bezel. I think in a lot of cases it is paint that had crept into the threads and dried which makes removal difficult. Good luck with the restoration and thanks for an interesting read.
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LJ,
As I mentioned under another topic, I have my father-in-law, a skilled clock entusiast, as a backup if I got in too deep.
Richard
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...and, yes, I did scrape around the housing/bezel junction to remove as much paint as possible.
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Hi
This is very interesting as I'm about to start on my Speedo.
Does anyone know where replacement or restored dials can be obtained? I got one made of plastic from the bike show at Stafford. It looked ok at the show but when compared to the original it's very poor quality so I'd like to find something better.
Cheers
Frank *smile*
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Frank,
This ought to give you a start in your seach for a speedo face.
Richard
http://www.vintage-motorcycle.com/index.php?language=en&site=9&suchtext=chronometric
http://www.petersclassicbikeparts.nl/index1.html
www.nisonger.com
http://www.speedorepairs.co.uk/
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Hi Richard
Thanks for the very quick reply.
The dials on the Austrian site appear to be the same as the one I've got. They have the wrong type face, ie sans serif. I think I may have to have mine refinished professionally then it will be correct.
Frank
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RE;Smiths chronometric speedos these are quite a simple thing to repair (if you can obtain the parts) seems like the speedo repairers do not like to give out info of source of parts for diy repair. Basically most chronos need a good clean thats all unless they have damaged mile/trip drum numbers you can easily source new dials in brass or aluminium .The hard to obtain parts are the parts that wear ie; the sandwich plates for mechanism & springs.I have repaired several chronos I normally give the mechanism to my mate who is a aircraft mechanic to have ultrasonically cleaned also I have used a good quality switch cleaner never use wd40 etc .I have replaced the mileage strips on the drums now this is a fiddly job but with a steady hand and a hands free magnifying glass it is possible.As for stuck bezels most bezels are past their best simple answer is to use a junior hacksaw & cut thru threaded portion once thru open up threaded part then remove dont cut deep or you,ll damage threads.Mind you I have made mistakes but have learned with time how to repair,you cant risk taking chances now at current prices for these speedos and if your not confident best left to someone in the know .Good luck if you do!!!! *eek* G/F DAVE
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Dave,
Too soon to know if I've done a right cleaning. Thanks for the advice regarding ultrasound. That would be a logical next approach if I have a jerking needle (no double-entendre intended).
Richard
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About 35 years ago I had a friend who was an instrument fitter in the airforce and I remember watching him work on some kind of instrument and he was using a pressure pack of some stuff to clean it. I think is was called Freon, but I'm not sure, it was a long time ago. I remember asking him about the stuff because it was amazing, just squirt it on and all the grease and grime just dissapeared.
Has anyone else heard of this or has my memory failed yet again ?
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Hi G/F Dave
Can you tell me where brass or aluminium dials can be obtained please?
Frank *smile*
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I do not know if Dave Woods will supply parts but he seems a reasonable chap I gave him my S/R speedo and rev counter and he repaired both and at a reasonable price.
The speedo on my Plunger is looking very sorry the bezel has had a screwdriver and hammer on it at some time but once fitted the ruber grommet in the cowl that it fits to hides it. the white paint on the dial looks as if it has been almost wiped off the word Smith can only just be read and the mileage numbers are very discoloured but at least you can tell what speed you are going.
Might get that overhauled sometime in the near future but I will not be going near it
Richard
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CIDER 1 I tried to contact my man who supplied with new dials but as yet he has not got back to me. I have a new dial in kilometers (180kph) if you are going continental. G/F DAVE
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Hi Dave
Thanks for the reply, but I think I'll stick with mph. A decent replacement will turn up sometime.
Frank *smile*
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Gents,
On checking the overnight (for me) new posts, I stumbled on the fact that I spelled "Speedo," "Seedo" when I started this topic. I apologize for having drawn others into my web of ignorance, leading to all posts in this topic with a "Seedo" heading. I couldn't live with it and changed all my own posts to the correct spelling. You all can change the spelling in your own posts, as you see fit, of course. I'd do it, being the guilty initiator, but I can't get to them.
For those of you who noticed my error and said nothing, so I might save face, my eternal thanks.
Erling, is there a spell checker here that I (and, it seems, others) have missed? If not, wish there were.
Richard L.
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a "Seedo" heading
Sigh! and here was I thinking of some sort of pornographic excitement comming from your speedo. It 'does' measure how fast you go doesn't it? *eek*
Hear Hear! for a spelling checker!
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Not sure where my spelling checker comes from ( probably the browser - Firefox) but it checks as I type.
I used to use a Sinclar QL computer that had a spell checker that checked and beeped with every key press, so you new at which letter you had gone wrong, you could then bring up a popup that would give you a list of suggestiond that you could select and insert.
Alas the QL had no internet facility so I now use the proverbial PC.
All the best - Bill
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Hello,
Because my top tree is from an A50, I think mine is an unusual approach for mounting a single Smith's Chronometric speedometer. Here are a few photos from before mounting the speedo. I found an obscure (I think) BSA part that goes under the fork nut and carries the more common instrument mount. You can see in the photo where I ground away part of this mount because it was never intended for the dropped ends of the A50 tree. Sorry if this is mundane, simplistic and something nobody else will ever need to do, but, I think enough of you are gadget-heads and bodgers that there might be some interest.
By the way, you can see the existing "Cateye" bicycle speedo in the photos.
Richar L.
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My Friend, that "obscure" part comes from either a RGS or a Lightning Rocket!
Trev.
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The RGS uses a longer finger bracket which is bent upwards. Other than that, it looks OK to me.
Trev.
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Gentlemen,
While I think I might have done a fine job of restoring my chronometric speedometer, I am yet to test it. Regardless of my perhaps illfounded confidence in the work I did on the mechanism itself, my stupidity continues to amaze me. There is a small fact about these mechanisms that I have now learned the hard way, specifically, they come in clockwise and counterclockwise versions. My speedo wants CCW (when looking into the input) and the cable is spinning in the other direction. "Hey, why isn't the needle moving?" was the first quesion to myself when I finally tried it yesterday.
So, one question I'm asking here is: is there a way to convert CCW to CW with the parts existent in the CCW mechanism? For example, might it involve turning over the escapement gear and that's it? Would the three little cams stay as they are? Obviously, I did not make a point of learning and taking into my soul every intricacy of the fairly complicated movement.
The other question I have is: is there an in-line gearbox I could get that is purpose-designed (or would just work) to solve this problem.
Your advice, sympathy and the indetectability of your snickering are all appreciated.
Richard L.
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I hope this is not obnoxious, but I am responding to my own post to keep the question on the front page, as I am anxious to resolve my speedometer problem. I believe that there are some in our group who can help, even if it's to say, "tough luck, Richard, it can't be resolved short of selling it off on eBay." Please don't be surprised or too angry if I repeat this process in hope of eventually getting some much-needed aid.
Richard L.
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Cider 1 /Frank,
I work with a chap who is a very good friend of Dave Woods the speedo man.Last time I visited Dave at his workshop I saw his selection of chronometric faces/dials (I think he said there were about 150 to choose from).I am pretty sure he will sell you a correct dial.He always has them for sale on his autojumble stall. He will know exactly what style you require for your model/year. If you get stuck and require any specific questions about repairing chronometrics ask me and I will find out the answer for you.
Mike
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Hi,
First, I am suffereing from name confusion, is it Frank or Mike? Frank, I think.
Anyway, thanks for this, I bet your contact with Dave Woods will pay off in getting to the bottom of my question, though, others, please still chime in. As it turns out, the dial face is fine. The problem is that the mechanism itself wants CCW at its input and the speedo gears at our transmissions want to deliver clockwise. I would greatly appreciate your putting this question forward with Dave Woods so I can learn if there is a "simple" fix. ("Simple" in quotes because, even if the mechanisms intended input rotation can be changed with existing parts, the work is going to be exacting and maticulous.)
If it would be easier for you and your workmate, I could contact Dave directly, if I was forwarded his contact information, that is, unless he is a recluse or adverse to giving away free information.
Thanks, again.
Richard L.
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Close, Its Mike,
Dave Woods phone number is 01243 542521 and he is near Chichester.He goes to most of the big autojumbles
To convert a chronometric speedo or rev counter from clockwise to ccw involves a complete stripdown and a small milling operation on the die cast chassis of the speedo .
The reason i know this is because he used to give the chassis to me to do the milling .
The other thing I know about chrono speedos is that any speedo can be rebuilt into anything you require. clockwise, anti-clock, rev counter, speedo,5" vincent ,even the "D" shaped bantam . They all use the same internal mechanism.
So a clockwise bantam speedo can be exchanged/converted into a 5" Vincent anti-clock rev counter.But it will cost you.
Mike
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Hi MikeN
Thanks for the info. I'll contact Dave later in the week.
Frank *smile* *smile*
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Mike,
Thanks, so much. This gives me hope (one of the basic needs in my speedometer rebuild). I will call Dave and ask if he is willing to share the specifics, then, I will need to decide if have the tools and skill to do the job.
Richard L.
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MikeN,
Do you have a drawing of the changes to the frame and would you be willing to share it?
Richard L.
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I haven't done any for a couple of years now, but from memory ; There is a small gear (they're all small), by where the cable enters the bottom of the chassis (it might actually BE the gear the cable enters)and it is retained by a metal plate and a small slotted cheese head screw. remove the screw, remove the plate and withdraw the gear. Set up in vice on vertical mill and with an 8mm slot drill ,mill the surface down 4.75 (3/16") lower.you re-tap the thread a bit deeper ,and re-assemble. And thats it.By lowering the gear that amount I think it brings it into mesh with another gear so reversing the drive (somehow. I never got involved in the details).I didnt do many as the majority of speedos go one way and only a few were specified the opposite.
Mike
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And another thing,
A tip I read for unscrewing the chrome bezels if you dont have any suitable tools is to hold the instrument face down in hot water so the plated brass bezel expands (brass has a higher co-efficient of linear expansion than steel).
Use a rubber glove for better purchase and give it a twist .
Making a GGRRRRNNNFF sort of noise at the same time could also help.
You can also make up a handle from a strip of steel with 2 holes and attatch it using the mounting studs. Which are ,I believe 6mm or possibly 0BA but not 1/4" BSF or cycle thread
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It's definatly 6mm. Did you see the strap-wrench approach I showed in the opening post on this topic? Also, thanks, again.
Richard L.
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The trip meter reset mount screw worked its way loose and I need to remove the dial to tighten the screw but I'm not sure how the pointer is attached. Is it a press fit on the shaft that can it be pulled off without tools?
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Hi azcaveman,
I was fortunate to have a pointer extractor tool from days long gone of calibrating pressure gauges, it is very simple, but one could be made out of a hex nut, thick wall tube with the bottom filed off suitable to make legs that clamp below the pointer. The opposite end threaded to take a screw with a "pin" turned suitable to fit the pointer shaft with a little clearance. Same effect as a run of the mill puller so to speak. The pointer is only a press fit. Despite having the puller, I have often removed the pointer using two screwdrivers under the pointer, with the dial face protected with a bit of card or cloth, carefully levering upwards, It should pop off without too much pressure and no damage....
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Hi All,
Recently I have seen the above and another reference to using a standard instrument needle puller
to remove the needle from a chronometric instrument
The needle fits onto a hollow sleeve so in my experience a normal puller can swell the outer end of the needle and
or put pressure on the inner spindle!
Not a good idea *eek*
I put the puller around the needle, clamp the puller in a vice and pull on the speedo so no pressure is put on the inner spindle
John