How to determine which surface to scrape first on a bed ways. - Page 4
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  1. #61
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    Quote Originally Posted by Lurk View Post
    Sorry folks, ignore everything from my last couple of posts related to the use of the box level - found out yesterday that one end of the vial was floating having come adrift from the 'plaster' plugs and the entire thing effectively not giving a reading of any use. (explains why Chris brought it down to mine). Had half an hour with my Hilgar Watts level and got some readings - will update later when Ive gone through it all with that.

    Mat

    PS Alex & Demon73 ; thanks for your comments - its precisely the fact you questioned things that made me repeat the exercise and question my results repeatedly. I am trying to verify each measurement now with two methods of measurement rather than one. That way if they don't match chances are there's a user error :-)
    I've got a box level like that, I noticed it wouldn't repeat. Not had it apart yet but sounds like a similar problem to yours.

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    Quote Originally Posted by Demon73 View Post
    I've got a box level like that, I noticed it wouldn't repeat. Not had it apart yet but sounds like a similar problem to yours.
    Here's the thing, it repeated sort of but then when I left it, it slowly drooped / moved to the shifted position. Looks like someone has had a go at trying to repair it by stuffing card shims around the vial ends. Thats going to be job for another day.

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    img_5953.jpgimg_5954.jpgimg_5957.jpg

    Spent a few hours shifting the lathe bed this morning and got it to a position where I can work on it from both sides.
    Managed to get some decent repeatable Box Square readings from surface 11 to check for twist. I also checked the gear box mount position and feed screw free end mounting position. All four readings (ends of each & mid positions are all in the same vertical plane - the set up was to use a mag base on the casting as a shelf to rest the base of the square on - then tip it back to the face to be checked and align it with a vertical (Engineers Square dropped down from the bed above).
    I repeated the exercise from start to finish several times to ensure I hadn't missed anything. I also placed some shims between the box square face & lathe face being measured to get the square as near as I could to vertical / horizontal - well within 0.001" as thats as thin as my shims go.

    I have also checked the surface 9 to 10 at 3" intervals and with a level at 6" centers (12" level so foot positions over lapped) - and micrometers over 9/10. Thankfully, everything gives the same reading within 0.0005" range. I then set up the KW sled and as per Alex' suggestion had the dti in front of the tube foot on 9. All be it only 5" in front. I checked it down three paths of surface 9 to ensure I covered the width.

    Am happy at this stage to say I know where the wear is on surface 9. Just to be sure - I then used a depth mic' 9 to D and got exactly the same readings as the 9/10 - so I am happy to work on the basis that surface 10 is not worn (also held a SE along 5ft of 10, and can't detect anything with a 0.001" feeler.

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  5. #64
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    img_6038.jpg

    Made a start on the first face, this is from early on - the central section was just starting to show ink on the print. I step scraped each end down by c 0.003" checking with a micrometer between cycles - once I got within 0.001" of the middle I started printing with the SE.
    It feels good to be making a start after so many weeks scraping SE.
    Mat

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    If I were scraping the bed, I would start using the least worn bed area's. That would be the tail stock ways as under the chuck it is original and the TS end is seldom used. So the TS ways are the least worn and still represent the Factory geometry.

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  9. #66
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    Quote Originally Posted by Richard King View Post
    If I were scraping the bed, I would start using the least worn bed area's. That would be the tail stock ways as under the chuck it is original and the TS end is seldom used. So the TS ways are the least worn and still represent the Factory geometry.
    Hey Richard.

    I understand that the TS ways up by the chuck should be A1, but how would go about keeping that plane scraping the TS ways? When I thought about it, seems like it could be easy to drift a little. No big deal side to side providing the drive shafts line up, but could make more work in surfaces 10 and 3 to get them coplaner if you ended up a few thou out end to end.
    As like this for example:
    example.jpg



    Cheers D

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    I'd expect he means to use the unworn ends to check (with Kingway, etc) that whatever OTHER way is actually being scraped is lined up with original surfaces..

    Could also mean to "scrape straight down" on it, so that it retains its alignment, which could probably be checked by measuring to the unlabeled lower surface below it, which will also be unworn (but might not be precise because it is only a clamping surface)

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    When we are rebuilding a lathe you follow the original geometry that the factory made. It's different then starting from a new machine build. So many complicate a "rebuild" trying to invent new ways to test things. You know people rebuilt and have rebuilt machines without a King-Way. It is a cool invention and it works super, but one can make a sled or use the bottom of the TS base to measure and test twist (level) off of. Jerry is correct, you scrape down following the original co-planer ways the builder used or left. One should count the number of scraped on each side of the TS V way so it comes down evenly. With a sled or a King-Way you scrape the high ends down to the low ends either with a longer then the ways SE or you step scrape it. Then "Match fit" the saddle and TS. Headstock if you remove it. Also you need to be sure you have the machine setting on it's legs, leveling jacks, etc, Not on some horses that you are assuming are the same height and co-planer. I have set beds on 3 points in some cases, but if you have the original legs or frame, assemble it and use it.


    I would say 99% of all machines were built right if it was made in the USA, Germany, the UK, etc. so you can do it this way. You can't say that with Asian machines, ever the early days of Japanese machines when we use to say Japanese Junk. Modern Japanese machines are just as good or better then many of the war machines. Remember what I say is to be a detective and measure things prior to scraping, machining, grinding. Have a game plan

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    Quote Originally Posted by Richard King View Post
    When we are rebuilding a lathe you follow the original geometry that the factory made. It's different then starting from a new machine build. So many complicate a "rebuild" trying to invent new ways to test things. You know people rebuilt and have rebuilt machines without a King-Way. It is a cool invention and it works super, but one can make a sled or use the bottom of the TS base to measure and test twist (level) off of. Jerry is correct, you scrape down following the original co-planer ways the builder used or left. One should count the number of scraped on each side of the TS V way so it comes down evenly. With a sled or a King-Way you scrape the high ends down to the low ends either with a longer then the ways SE or you step scrape it. Then "Match fit" the saddle and TS. Headstock if you remove it. Also you need to be sure you have the machine setting on it's legs, leveling jacks, etc, Not on some horses that you are assuming are the same height and co-planer. I have set beds on 3 points in some cases, but if you have the original legs or frame, assemble it and use it.


    I would say 99% of all machines were built right if it was made in the USA, Germany, the UK, etc. so you can do it this way. You can't say that with Asian machines, ever the early days of Japanese machines when we use to say Japanese Junk. Modern Japanese machines are just as good or better then many of the war machines. Remember what I say is to be a detective and measure things prior to scraping, machining, grinding. Have a game plan
    Agree with all of that Rich, tbh honest I dont see the two plans as being that different. The main focus of both approaches is to get the TS ways in first and work from there.
    I do see one important advantage by taking the suggested route, and that is you can treat 7 and 8 as individual surfaces, where youd have to consider them as a pair working the TS surfaces alone. Sure thats no problem if youve some mileage but it can be the source of a lot of brain ache as a novice (no disrespect Mat ). Youve already got enough tugging your brain space to get you off into the woods , so if the situation offers you a bone, why not take it.

    The situation as best I can tell not standing over the machine is:-
    The machine is up on bases and level.
    We have the luxury of a known factory reference in 10, simple to go straight down in 9 as Mats done.

    From here:-
    Easy job to bring 6 in with 9, we have the luxury of levels and a KW, why not use them.
    We can now indicate 7 or 8, end to end to evaluate the usefulness of B. +/- a few were good to go. +/- .020" its a old Japanese pos . Time to re-evaluate.
    If B checks out ok, 7 and 8 are childs play to bring in clocking from the KW.

    All up I think Mats doing well, maybe overly cautious and thinking to much at times, but I remember being like that when I did mine, its normal. Looking forward to the progress

    PS:- Be a nice idea to rough scrape the TS base to the surfaces under the HS while we have the opportunity

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  16. #70
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    See I had the advantage I learned all this from generations of pro's teaching each other. This why you come here right? So you can ask pro's like myself, Ironsmith, Tyrone, Phil down under, RC, Jerry, etc.. We have been paid by people to do this as a profession. It's not our first machine and we are not guessing or asking amateurs for help. The test in time will be the results. Your way may seem good for you now, but from my perspective I am not guessing as I have done more then one, my Dad did more then one and the Journeyman who taught him did more then one. As time goes on you will discover some clearance surfaces were not machined perfectly as the ways.

    They were planned on the machine at the same time, but they are clearance and the builder didn't care if the finish was as fine as the ways. I would suspect your way will work and I would not be wasting my time with a square to get the bed ways a perfect 90 or 45 degree as how do you know if the builder cared if it was a perfect angle? He may have just set the angle using the graduation on his compound and it's off a degree or 2. Just scrape evenly down and follow the original angles and then "Match fit" the riding surface.

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    Well im not alone in thinking taking surface 9 first is a good idea Rich, and I think im well aware of the difference between a precision and clearance surface, which Is why I suggested checking it.
    I come here to learn from the pros, yourself included, help out where ive the experience, and of course have the occasional giggle . Weve a difference of view which im cool with, wouldnt be the first time. Like you said 'The test in time will be the results, and theres more than one to skin a cat'. So with that ill leave this exchange here I think.

    Cheers
    D

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    img_6154.jpg

    img_6191.jpg


    Following on the plan developed earlier in the thread - the TS flat way is now nearing completion - a small area of misalignment below the HS end. Ive left that to massage when I finish scrape the length. When I have a few minutes I will upload an image showing the condition of the TS flat way below the spindle - its had some trauma for sure and with the HS in place there would have been no way to use it. The TS end was also worn by 0.002" and had some serious dents (looked like the edge of several round hammer blows) - as RK has repeated more recently - measure everything & be the detective and then develop a plan.

    So far so good.

    Mat

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  21. #73
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    Well, I thought I should close this thread with the bed scrape completed - I followed the step by step plan and it pretty much worked like clockwork. I kept a track of the hours spent - just for interest. The first face was the saddle flat - which took c 14hrs. The next was the Tail Stock Flat, that took c 12hrs. The inverted V of the TS each face around 9 hrs, and a little less on the saddle V. All in - 40 hrs. I could spend another 10 hrs refining the faces and PPI - but at this stage I am calling it done. End to end, running the metric clock along its within +/- 0.005mm
    The images show the final face - the inside saddle V. (For scale - the face is approx 3/4" wide).

    img_6317.jpg
    img_6318.jpg
    img_6319.jpg

    Going to take a look at the saddle next, then the headstock & spindle alignment - the latter is looking to be interesting as the white metal bearings are shot ;-)

    Thanks to everyone that has contributed to this thread and others I have started - without their ideas, support and encouragement I would not have achieved much of what I have to date. Special thanks to Duncan for the 'plan' its just so much clearer when you draw things rather than I try and describe them ;-)

    All the best
    Mat

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  23. #74
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    Glad it all worked out well mate. Looks like youve done a top job, curls n all.

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    Quote Originally Posted by Demon73 View Post
    Glad it all worked out well mate. Looks like youve done a top job, curls n all.
    Don't worry D. I am saving some scraping for you when you come up. I thought you might like to take a look at the double dovetail cross slide / taper turning arrangement - might prove a challenge to maintain alignment

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    Quote Originally Posted by Lurk View Post
    Don't worry D. I am saving some scraping for you when you come up. I thought you might like to take a look at the double dovetail cross slide / taper turning arrangement - might prove a challenge to maintain alignment
    lol, I think looking at it is all ill be able to do for a little while mate, today was a bad day at the office thats gona sting for a good while.

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    One of the important things I teach in my classes. Is to be a detective and measure everything. If you are trying to keep everything co-planner or original. Scrape the worse or most worn place on the two riding ways in the same system.. Or sat the Tail Stock ways or the saddle ways. You scrape the most worn to scrape the it to the bottom of the wear and then scrape the opposite side to the same depth to keep the ways co-planer.


    There are other things to consider if the ways are longer and you have a shorter riding part then you can correct the geometry with the shorter matched fit side in some cases. But to answer the question generally. Like the top of a knee on a milling machine and you need to keep the knee square to the column ways then you scrape the most worn side first and then scrape the opposite side or less worn last.

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    Hi from downunder

    I have two Holbrook T13's myself. This is an excellent thread for me to follow and learn ! My 13's have both suffered years of abuse , I just missed out on buying a mint T15 model that was on ebay .... Mike

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    Mike you are lucky to have an amazing machine rebuilder down there who also teaches scraping classes from time to time: He is also a member on here Machtool and another aussie member with a Chirchil way grinder in his shop is RC99. Here is Mactool info: These guys are pro's who are not guessing.

    Phillip Fehring
    P & L Machine Tools Pty. Ltd.
    24 Bostock Court
    Thomastown Victoria 3074, Australia
    Tel: +613 9466 3655
    Mob: 0412 555 326
    [email protected]

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  33. #80
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    Quote Originally Posted by Sheraton2 View Post
    Hi from downunder

    I have two Holbrook T13's myself. This is an excellent thread for me to follow and learn ! My 13's have both suffered years of abuse , I just missed out on buying a mint T15 model that was on ebay .... Mike
    Glad it has / will help you Mike. As you have probably worked out for yourself - Im no machine re-builder, just trying to learn as much as I can while doing it for my own benefit and sharing what ever comes along - the input from the forum members on these threads has been beyond anything I could have gained from a few days on a course - I think the fact you get to re-visit the thread as often as you like and get a pretty good explanation of each theory is worth its weight in gold. That being said, Im sure if you get the opportunity and can resource it- a machine re-building course would be a fast track to get up and running. I know there are some guys in a 'club' run out of Marcus Hugh Christensens' workshop (Queensland )- he's on this forum and hopefully will drop you a line. He's got some acreage of granite and a selection of straight edges and other gear which he and the club have been hoarding for some time :-) - he's also a very nice guy :-)

    Meanwhile, if you want to follow the T13 rebuild, I am uploading progress on my YouTube channel (Look Creations YouTube) - as and when I have some useful info' / questions I will start a new thread on these pages - this last week I have been tearing the clutch assembly appart. Also worth a look at the Yahoo Group of Holbrook Owners if you are not already a member. Let me know if you want a link.
    All the best
    Mat


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