Bright mild steel

  1. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    Hi , chaps , I am an avid wood turner and have been using my home made lathe since 1983,it has had several iterations ,latest of which is an inverter drive set upwhich has transformed it's capabilities , the final tweak I want to improve is the alignment of the tailstock on the bed , the bed is made up from 2 8ft I beams ,my question is, how straight is bright mild steel strip , my thoughts are a piece on top of each of the beams fixed with counterbored pan head screws, would the stock material be straighter than the I beams ?..
    Cheers
     
  2. hotponyshoes Member

    Messages:
    2,934
    Location:
    Somerset. Uk
    Ground flat strip is available, if you bolt it down it's just going to twist to however bent the beams are though so it wont be any more precise than what ever you have to measure/adjust/pack it with.
     
    metalmelt and pressbrake1 like this.
  3. frank horton

    frank horton V twins are great but 4"s rule.........

    Messages:
    2,068
    Location:
    Soon 2 B Crete
    I'd just tickle to the high spots till ur happy.....if they are not to far out of line...
    check for twist over the length FIRST.....
    I needed a couple of press blocks...used I beam but gave them a quick clean on the mill....
    surprising how outta shape the were....
    got any photo's.....?
     
  4. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    20200823_070237.jpg 20200823_070237.jpg Hi , thanks for replies, here's a couple pics, the edges of the bed are rounded so not best bearing surfaces the tailstock is from an engineers lathe , came from Grytviken South Georgia, the headstock is from a 56lb weight the, the bed us from 2x 8ft galvanised fence posts , tool rests al,home made , 6 ins swing , 6 ft between centres , headstock rotates for big stuff , 0.55kw motor vsd controlled, has controllable ramp up , down rates , variable speed , reverse and jog facilties , the only bit that is a bit iffy is the tailstock alignment when remounting or drilling ,obviously this is only the 18 inches or soup to the headstock , for between centres and longer work its not critical ,sorry for the messy state but am busy making nest boxes
    Cheers
     
    • 20200823_070309.jpg
    dyno-tron likes this.
  5. RichardM Member

    Just to re-cap, problem you have is tailstock alignment, laterally and not vertically?

    So why not get two strips of ground stock and screw it to the underneath of the I beam internally so the tailstock base runs between it? This would allow for more accurate side alignment as long as the tailstock base is machined to fit between the ground stock.
     
    metalmelt likes this.
  6. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    The centre height is fine it's the lateral side to side that's the problem , maybe I will get a piece of steel plate milled paralell to replace the ptfe block , the gauge plate at the headstock end seems a very good idea as it won't affect anything else ,
    Thanks
    Chris
     
  7. Spark plug

    Spark plug Member

    Messages:
    3,683
    Location:
    Durham, England
    It may be more cost effective, and produce better results to replace the I beam with say 40~50mm round H&G linear shafts + bearings.

    It may mean a big re-work but the results would be well worth it.
     
  8. Maker

    Maker nEw mEmBeR

    Messages:
    7,665
    Location:
    Don't ask questions
    Or take the bed to someone with a big planer and get it trued up. :D
     
    Milkybars, pressbrake1 and mtt.tr like this.
  9. RichardM Member

    Is the PTFE attached to the tailstock base and the clamp plate pulls up under that to secure? If so change it for a steel plate screwed to the bottom of the tailstock mount, nice close tolerance to the I beam, a couple of location pins so it doesn't move as well would be good. That might give you the results you are after without having to use ground stock.
     
  10. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    Hi , yes I used ptfe because the original bed was 100 x 50 box , Ihave a bit of 10 mm steel , just meed a friendly chap with a milling machine or decent lathe now, the bed is welded (sort of ) to 100 x 100 box at each end and held reasonably paralell with m12 studding and nuts inside and out in 3 places , these iirc got it pretty paralell, any one in SE Cornwall got a mill ? The metal Ihave is milled flat and paralell it would just need 1 edge milling , here's hoping , the idea of 50 mm linear shafting is a good one but waaaaay out of my budget which is virtually nil, now a pensioner , my wife's pension being deferred for 6 years money is a bit tight , that's why Iam making nest boxes to sell ,
    Thank you for your replies ,
    Chris
     
  11. RichardM Member

    What size steel plate do you need?
     
  12. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    Hi measured up today , the bit of the bed that is most used when drilling with tailstock has a gap between of about 75 mm at a guess , but there is about 10 thou or so variation in that area , I can measure accurately tomorrow but notionally 75 x 100 x 10mm thick .
    I have a bit from an old machine which is machined all round but would need one edge milling paralell after I cut it with an angle grinder , fortunately the gap on the bed is adjustable by altering the 12mm studding between the rails , this would allow a best fit scenario with a decent block to adjust to , sadly I no longer have access to metalworking machinery ,
     
  13. RichardM Member

    I'll have a look in my steel bits tomorrow for a bit that size.
     
    rosinante likes this.
  14. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,659
    essex england
    Quick kiss with the planer on the side shears and it would be better than 99% of metal lathes
     
    Maker likes this.
  15. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    Not a clue what one of those machines is , or even who would have one here in Cornwall,
    Chris
     
  16. RichardM Member

    I have a piece of BMS 10mm thick, 75mm wide (actually 74.95, 74.91, 74.94mm along the length) 180mm long. If it would work for you just pay for postage.
     
  17. rosinante

    rosinante Member

    Messages:
    1,097
    Location:
    Cornwall England
    Hi , have measured with my el cheapo digital calipers , the runner under the tailstock is 76.86 ish mm
    Have found a garage with a mill and they will run my bit thru to suit for cheap , thank you for your idea and offer of material ,
    Cheers
    Chris
     
  18. RichardM Member

    Glad you've got it sorted.
     
Advertisements