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New Guy: Upgrade Parts Or Entire Lathe?

Discussion in 'HARBOR FREIGHT, CENTRAL MACHINERY & BUSY BEE' started by mzvarner, Apr 8, 2016.

  1. mzvarner

    mzvarner United States Active Member Active Member

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    Hi all. New to the home machinist world. I recently purchased a used Central Machine 7x10 (SKU 33684) and I am really enjoying the process, but already finding myself wanting a larger lathe setup. I have ordered a number of parts from LMS to get setup including; Tormach QCTP/ tool holders, tail stock jacobs chuck, various tooling/ drills/ center drills/ boring bars, 4" 4 jaw chuck with adapter plate, and most recently the LMS metal gear kit. While i was placing that order I noticed they make an aftermarket extended bed kit which looks to be compatible with my machine.

    So this got me thinking of 2 choices. I can purchase the bed extension kit and the extended cross slide kit then swap all the existing parts over (ultimately saving money this route and having a lathe bigger in both axis). Or I can sell the current Central Machine lathe and use that money towards the largest lathe that all the equipment I already purchased is compatible with (Grizzly 8688, maybe the Grizzly 7x14)

    Honestly the more I think about it the more I want to swap parts over to the bed extension. I would get a longer bed and more cross slide travel and save money this way, assuming that all the existing machinery (mainly tail stock and carriage) are compatible with the bed extension (i.e. they all have the compatible front way track that is semi triangular).

    Just in case it makes a difference I am using this mostly for fun to learn a new skill, simple DIY projects, and home gun smithing. Eventually my wife and I are going to get acreage so I imagine at some point I may end up with a larger one yet but the bed extension should hold me over till I move out of a garage and into a shop.
     
  2. TOOLMASTER

    TOOLMASTER you don't want to know Active Member

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    you can find a nice used lathe, just be patient. they come up
     
  3. kd4gij

    kd4gij United States Active User Active Member

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    To use the tooling you already bought. May as well upgrade it and save the money. No matter how big of machine you have there is always times you wish it was a little bigger.
     
    X-RAY likes this.
  4. Redbird

    Redbird United States Iron Registered Member

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    I have the grizzly 7x12 lathe and did the upgrade to 16", was really easier than i thought, and that extra 4" make a big difference.
     
  5. mzvarner

    mzvarner United States Active Member Active Member

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    Can you comment more on the process? I assume you used the LMS bed extension kit? or is there another option on the market I have yet to find?

    There are not many reviews of the process that I am able to find. I know that there is some Drilling/ tapping required. How hard is it to drill a straight hole in cast iron? The instructions say you only need an electric hand drill. There is one multi video review on you tube of the process and the author ended up having to drill a new hole for the change gear guide screw. Any other issues/ advice you can add? I am really leaning in this direction but I am new to the process and want to make sure I am not going to get in over my head and end up with a wasted casting w/ broken taps/ misaligned holes and just end up buying a Grizzly 7 x 14 (if all my parts will transfer)
     
  6. Redbird

    Redbird United States Iron Registered Member

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    I used a hand drill for all tapped holes, really didn't have any problems, the cast iron taps very easy. If i remember one tapped hole for the rack I think fell on a radius on the back side which made drill and tapping that one a little hard. It take some time to line up the rack with carriage and cross-screw so they do not bind. This is done by clamping bearings blocks that cross-screw runs in. When you can move carriage from one end to the other without binding. transfer punch location of top holes. Drill and tap. than install screw and do same for bottom ones. This part takes time to get right but is not hard. The motor mount for this unit fits but it is very tight and a pain to get in place but it can be done. Would I do this conversion again, in a heart beat. http://littlemachineshop.com/Instructions/5000BedExtensionKit16.pdf this link will get you the complete instruction for the upgrade. Any question feel free to ask.
     
  7. P T Schram

    P T Schram United States Active Member Active Member

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    You should sell me your little lathe so I can use it to make a welding positioner. Use the funds to find a nicer lathe :)

    (I have yet to find one of those lathes on the secondary market)
     
  8. Redbird

    Redbird United States Iron Registered Member

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    I got mine off Ebay, 7x12 Grizzly, since then have add the 16" extension, reworking head for taper roller bearing with seals. Purchase spindle out of England to take 4" chucks without adaptor. It has been a really Great little lathe.
     
  9. mzvarner

    mzvarner United States Active Member Active Member

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    @P T Schram- Ill keep you in mind should that day come :)

    So I ordered the complete metal gear kit from LMS (mostly b/c i dont have any change gears) but also in case I broke the rest ( which i did last night). So there is not a lot on swapping gears on the internet that I can find. Most of the resources are upgrading the spindle bearing to a tapered bearing, and it looks like this process requires a press. DO I need to use a press to change out the various gears? Is there directions in the LMS gear kit or can some one point me in the direction of a good resource?
     
  10. Redbird

    Redbird United States Iron Registered Member

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  11. mzvarner

    mzvarner United States Active Member Active Member

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    How much force did it take to seat the new taper bearings on the spindle? I got the micromark kit today and tried to reassemble things but the taper bearings require so much force that I rip the fixture out of the vice while trying to press the bearing onto the spindle.

    Now to be fair, I was under the impression that the new tapered bearing kits came with the kit (they didn't) so I took the original bearings, spindle, and head stock to a local bearing supplier who had them in stock and all the measurements where the same (so they should work)

    Am I doing something wrong? I am thinking of taking it to les schwab and seeing if they can press the bearings for me real quick.
     
  12. royesses

    royesses United States H-M Supporter - Premium Content H-M Supporter-Premium

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  13. Redbird

    Redbird United States Iron Registered Member

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    when installing taper bearings you need to make some spacers 2 of them 1.25mm thick if I remember, I still have not put the taper bearing in mine, order some precission washers McMaster Carr am hoping will work out. I got my tapper bearings for LMS.
     
  14. mzvarner

    mzvarner United States Active Member Active Member

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    This project may be the death of me. For those in the market, do your research and before making the purchase of one of these lathes used, make sure it has all the parts, or that your going to easily replace the missing ones.

    My new spindle (i know not needed) from London that allows use of the 4 jaw with out an adapter showed up. So I start assembling and I notice more and more parts are missing. Can some one please assist in making sure this next order to littlemachine shop is complete!

    1 I am missing a bushing for the b/c gears. I have one for the 80 tooth gear, but ont one for the 40. ( I was missing all change gears when I bought it and the previous owner used about 8 washers to take up the space of the 40 tooth).

    2 I also need a pinion bolt for the lead screw drive.

    The photo below is how the lathe came, before I tore it down. You can see the half dozen washers and missing pinion(?) Hope this helps.

    1RWWtRo.jpg
     

    Attached Files:

  15. Redbird

    Redbird United States Iron Registered Member

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    Looks like 2 spanner nuts that go on spindle are missing or am not seeing them. If I get time, can take a couple pictures of mine for you to look at, I to got the spindle for 4" chucks. Will be in shop today and will take a close look at mine.take few picture, Mine is in running order but broke down to bare parts where I have been upgrading it.
     
  16. mzvarner

    mzvarner United States Active Member Active Member

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    I started tearing down before I took the photo then decided a pic was probably a good idea. The spanner nuts are in my possession.

    Some better pics would be awesome and much appreciated. I know there are some on the internet but most are grainy and of poor detail.
     
  17. Redbird

    Redbird United States Iron Registered Member

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    will see what i can do today for, i started tearing mine down, having more fun modifing it now than anything, lol.
     
  18. mzvarner

    mzvarner United States Active Member Active Member

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    I totally get the fun with modifications!! This has been very frustrating but also a cool learning experience because, by trade, I am not mechanically inclined. I can't wait to get it up and running. Then next month I will order the extended bed kit and then have a very useful tool for life... I mean it would be foolish to part with it at this point with all the emotion invested.
     
    Tozguy likes this.
  19. mzvarner

    mzvarner United States Active Member Active Member

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    So I got the lathe all put back together and was going through a break in procedure for the C3 lathe (incrementally increasing RPMs at 10 min intervals) and I noticed a "hot smell". The head stock was warm to the touch. I looked into preload for these new bearings but did not see too much. Is some heat to be expected now with metal gears and new bearings? For lubricant I used white lithium grease in the bearings and head stock gears.
     
  20. Redbird

    Redbird United States Iron Registered Member

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    not done my yet, but sounds like you have to much preload on bearings, need to back off just a touch......
    \
     
  21. mzvarner

    mzvarner United States Active Member Active Member

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    I was going to adjust the preload but when I took the nuts, gear, and spacer off I noticed lateral play in the spindle. It looks like this is just play that is inherently there because of the design of tapered bearings. This play goes away when the spacers and everything are installed, and before my drive belt tore I had the dial indicator setup and I was getting maybe .0005 of deflection on the outer surface and inner bore of the spindle. This sounds ok to me!? The only issue I noticed is that the spindle gear is not fully engaged so I think I need to trim a few thousandths off the spacer so the gear will align correctly. This should help with preload as well because then I won't have to crank so hard to get the gear to align. Sound about right?
     
  22. Tozguy

    Tozguy Active User H-M Supporter-Premium

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    Are you sure about the white lithium grease for the bearings?
     
  23. mzvarner

    mzvarner United States Active Member Active Member

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    No I am not. It is what Frank Hoose recommends on his website and you tube channel about the mini lathe/ mill. Its what I had on hand, but I am sure that at some point I will break it all down again and apply something else. Any recommendations?
     
  24. Tozguy

    Tozguy Active User H-M Supporter-Premium

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    I asked because the white lithium grease I have is a general purpose, good for many things grease that might not be best for your specific application. My lathe spindle bearings run in ISO 32 oil so it doesn't compare. However I have experienced heat generation in bearings from using the wrong grease in the past. New bearings should not overheat unless preload is too high, they are binding or the wrong grease is used. It is normal for bearing housings to get warm to the touch, even when set right, but not too hot to touch, to smell or smoke. My reflex would be to follow the manufacturer's recommendation but I know nothing about your particular lathe.
     

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