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G0768 Compound Modification

Discussion in 'GRIZZLY INDUSTRIAL INC.' started by tegelermusic, Mar 28, 2016.

  1. tegelermusic

    tegelermusic United States Iron Registered Member

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    Hello everyone!
    This is my first official post so I thought I would share a video I just made showing a modification I made to the compound on my lathe. I really like my lathe but was disappointed at how inconvenient it was to change the angle on the compound. I thought - "There has to be a better way" Well I think I found a solution and felt it would be great to pass the idea along to all of you who are also frustrated with this issue.

    Keep in mind I'm new at creating shop videos and unfortunately didn't capture all the footage I wanted to but I think you can get a good idea of what I did to accomplish this modification.
    Remember I'm new at this so be gentle with the comments ;)

     
    Billh51, hman and gerald guenard like this.
  2. ch2co

    ch2co United States Grumpy Old Man H-M Supporter-Premium

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    Welcome aboard! I think that you are going to like it here.
    Your first video is better than a lot of guys that have been with it for a long time. Congrats!
    Your compound angle adjustment screws are definitely a lot harder to get to than mine.
    I just finished making a new compound clamping plate for my G0602 and it made a LOT of difference
    in tool stability. You might look at RJ's clamp that I just copied
    Improved G0602 Compound Clamp
    I don't know if it or something like would work in
    your case, but its worth looking at. The problem with
    the 0602 is that the two clamping screws provide a way for the clamped compound to rock from the front
    to the back of the cross slide. This modification clamps the compound at 6 points and really makes a big difference
    in rigidity.
    Again, welcome!

    Chuck the grumpy old guy
     
  3. Ulma Doctor

    Ulma Doctor Infinitely Curious Active Member

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    nice video, well done!:)

    a little thing to point out, when you had set the compound to 30*, you really set it to 60* to the lathes longitudinal axis.
    you'll need to swing the compound towards the headstock another 30* if you are going to thread using compound feeding method .
    i made the same mistake, but it was a few years back.:grin:
     
  4. Garththomas

    Garththomas Canada Active Member Active Member

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    Good video and thats a good mod, I just ordered my G0768 today and look forward to seeing more from you. No pressure though LOL.
    Thanks for posting it.
     
  5. Garththomas

    Garththomas Canada Active Member Active Member

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    I should have asked how did you go about machining the dove tail part.
     
  6. tegelermusic

    tegelermusic United States Iron Registered Member

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    Wow, a lot of comments already. Looks like this is going to be a fun place to be.

    About the 30* setup...thank you for correcting me on that. It never looked quite right but since I haven't done any threading yet there wasn't a chance to see how bad it would have worked. There is also a technique I heard about to set the compound at 30* and you get a 2 to 1 ratio when feeding in with the compound instead of the cross slide for taking off very small amounts of material. Does anyone know about this and the proper 30* angle for that procedure?

    As far as creating the dovetail I used the tool that came with the cheap blue carbide tip tool set from Grizzly that I think is meant for cutting threads. It is pretty narrow and comes to a sharp point. I just set the compound to the angle I wanted and slowly started shaping the cylinder into the dovetail just feeding the compound down into the corner. There was no specific angle, just what looked good to me and then I ground the brass pins to match the angle on my grinder.

    Oh yeah, and Chuck I tried the link to the Improved G0602 Compound Clamp but it didn't work. I'm very interested in learning about anything that stiffens up these small lathes. Not that I'm saying I need or want to spend the money on a bigger lathe, it's just easy to see the advantage of having a solid tool setup. So far I've not had any projects that I couldn't do on this lathe as long as I take my time. Besides I'm having a really good time learning so why hurry ;)
     
  7. Garththomas

    Garththomas Canada Active Member Active Member

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    I have another question regarding your lathe, in the manual the recommended lube for the gear box is grease but I think that was a typo because I see a window in front that looks like its for checking oil.
     
  8. tegelermusic

    tegelermusic United States Iron Registered Member

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    There is no oil window, there is only a set screw that you can take out to squirt additional grease in if it starts to get noisy. In the book it says to grease yearly or as needed (if it gets noisy). Honestly I get to use it so little that I've not had any need to grease it in the first year. It's sounds the same as the first day I started making chips. When I get a chance I'll open it up and check the condition of the grease and probably re-grease the whole thing.
     
  9. Mattm23

    Mattm23 United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Nice work. Thanks for the video
     
  10. tegelermusic

    tegelermusic United States Iron Registered Member

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    Thought I would do a quick update on my lathe.

    I was using it the other night and started having a couple of problems.
    1st the motor suddenly stopped working. The RPM readout came on and both fuses were good but no motor.
    My immediate fear was I pushed it too hard and burned up the motor, but after pulling the motor out I found that one of the brushes caps was loose (there are 2 on my motor). I did a quick inspection and cleanup of the brushes and tightened both caps down... success the motor was working again.
    After getting back to work I noticed a slight squeaking noise and shut everything down. After an hour of searching I finely decided it was the spindle bearings. I was thinking what else could go wrong but I'd better take it apart and check things out.
    Of course, just like anything I want to learn about these days, I went to YouTube and found a couple of spindle disassembly videos on similar lathes and started going to work. When I got the spindle out I couldn't believe how dry and waxy the bearing grease was and how little there was on the bearings.
    Luckily there was no visible damage to the bearings so I headed out to my local Farm & Fleet store and picked up the bearing grease that Grizzly recommended in the manual. After cleaning off all of the old grease, re-packing the bearings with the new grease and putting everything back together, I can't believe how incredible this lathe now operates. This thing has never run this smooth.

    The lesson learned: Don't rely on the bearing grease applied at the factory. I have no idea how long that lathe sat in a warehouse before I started using it so who knows what kind of shape the grease was in when I first turned it on. Even with doing the spindle break-in as listed in the instructions I don't believe there was enough grease in there to fully coat the bearings in the first place so I feel lucky to not have not had any permanent damage to the bearings.

    My advice - If you don't think your chuck is spinning freely enough take the time to learn how to pull the spindle apart and get some new grease in there.

    My test was putting the lathe in neutral and giving the chuck a spin. If it stops right away your bearings could be getting dry.
    Or it also might be that the spindle spanner nuts are too tight causing excess drag on the bearings. When putting mine back in I only tightened the spanner nuts enough to just take all of the play out of the spindle.
    Now when I run mine up to say 1000 RPM's and turn it off it actually coasts to a stop instead of stopping right away and it also runs much quieter.
     
    grmccaf, turnitupper and T Bredehoft like this.
  11. Garththomas

    Garththomas Canada Active Member Active Member

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    So the videos you found were pretty well correct about spindle disassembly? My chuck spins around two times when I do it by hand.
     
  12. ch2co

    ch2co United States Grumpy Old Man H-M Supporter-Premium

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    The grease that I have found used in various Chinese mechanisms is deplorable. My lathe and mill were well used when I got them and this matter had already been corrected by the previous owner. I have worked on several Chinese telescope mounts where precision should be of utmost importance, but like other machinery from over there, the only to get them working properly is to tear them apart thoroughly clean out all of the black tacky muck that they use as grease and grease them properly before reassembly. I also found pieces of metal debris stuck in the gunk and it wasn't from use. The price we pay for these items are low in comparison to the stuff from other manufacturers and this is one of the reasons why. I personally like the fact that you can learn about these mechanisms by rebuilding them from their original state by rebuilding them. Think of it like an education.

    CHuck the grumpy old guy
     
  13. Mach89

    Mach89 United States Active Member Active Member

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    Great video. I have a G0765 lathe with the same compound issue. I do believe I will be going this route (or something very similar) to modify mine as well.

    Sent from my SAMSUNG-SM-G891A using Tapatalk
     
  14. tegelermusic

    tegelermusic United States Iron Registered Member

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    These 2 videos helped get a good idea how the spindle is assembled.
    <iframe width="560" height="315" src="" frameborder="0" allowfullscreen></iframe>
    <iframe width="560" height="315" src="" frameborder="0" allowfullscreen></iframe>
    A big thank you to these YouTuber's for educating us newbies.

    Mine now spins about two turns when spinning by hand when in neutral.
    Before the repair I might have gotten a 1/2 to 3/4 turn before it stopped.
     
    bowcoastie likes this.
  15. stioc

    stioc United States Iron Registered Member

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    Are you happy with the lathe the lathe overall? I'm trying to decide between the G0768 and the G0602. I like the variable speed on the 768 and from what I gather the ability to cut left hand threads out of the box on the 768. It's my first (ok second, i briefly owned a HF 7x10 and then sold it after losing interest) lathe and will compliment my recently acquired RF-30 Milling machine.
     
  16. tegelermusic

    tegelermusic United States Iron Registered Member

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    Now that I've fixed my spindle problem this thing works great for what I'm doing with it. Do I wish it was bigger, of course, but I think that's the same problem as most lathe owners. This is what fit my budget at the time which is always the deciding factor for me.
    Honestly though, I am very impressed on how big of projects I've accomplished with this thing. Can I take 100-200 thou cuts on steel parts? No, but I'm generally never in that big of a hurry and I'm not trying to make my living with it. This is suppose to be a fun hobby and learning experience for me so if it takes a little longer I don't really care.

    I do like the variable speed especially if I start getting a little chatter I can make a quick adjustment to the speed to hopefully help the problem.
    The only thing I've had issue with is I wish it had a little more torque at the slower speeds of course that comes from the chatter I get when trying to drill 1" holes in steel parts. Maybe that's asking a little much from this machine. I should probably just use a boring bar to get to my larger hole diameters.

    One thing that I must mention is that I have not done any single point threading on this thing yet so I can't give you a good assessment of how it performs with that task. I'm sure it's just because of the hassle of changing out those gears but threading is something I want to learn so it's on my to do list just so I can get used to the process.

    I don't know if any of this helps with your decision but no matter what way you decide make sure you share your journey with the rest of us.
     
  17. RJSakowski

    RJSakowski H-M Supporter - Premium Content H-M Supporter-Premium

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    A compound angle of 30º to the spindle axis advances .5" in the x direction for every 1" advance of the compound. An angle of 11.53 advances .2" and an angle of 5.74º advances .1" along the x axis for every 1" of compound advance.
     
  18. tegelermusic

    tegelermusic United States Iron Registered Member

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    Thanks RJ, I'll write those numbers down.
    I thought I heard someone talk about it on a YouTube video but then I couldn't find it again so thanks again.
     
  19. stioc

    stioc United States Iron Registered Member

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    Thanks for the feedback! Did you by chance consider the G4000? It's the same price as the G0768, just bigger/heavier and gearbox driven than variable speed. I can't decide between these two machines. As much as I want the variable speed the G4000 seems to be more substabtial and the 9x20 size makes it more appealing.
     
  20. bowcoastie

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

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    If anyone is going to do this job on the G0768, you need to be aware that the speed sensor is engaged around a sensor ring that is bolted to the spindle. To properly remove the spindle and do the bearings one has to take the front cover off where the speed DRO is and loosen the two Allen head screws to remove the sensor. Then the rest is just like the videos. The second video was very helpful.
     

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