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Thread: Graham's Optimum BF20 Build

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    Default Graham's Optimum BF20 Build

    I want to start by saying hello to everyone here. I have been lurking around for a little over a year. Also, thank you to everyone with a build thread and if some aspect of something I am doing looks like something you came up with, it probably is, so thank you for the inspiration and help.
    I have the design for the x and y-axis almost complete. I have not started the z-axis because I have not fully measured the column, head, or head mounting plate.
    I am still trying to figure out where to mount the control box, which connectors I want to use, and what motor I want to use, DC or 3 phase AC with a VFD. I found a Baldor motor (VM3550) which looks promising because of its small diameter, but it is not rated for inverter use. Has anyone used a regular motor with a VFD?
    Scott from benchtop precision has been making some parts for me and the quality of work he does is excellent.

    Anyway here are some pics of what I have been up to:

    I bought the mill through Grainger before the prices went way up. I also got a little bit of a discount from the sales guy. Here is how the mill showed up:


    Here it is setup in the garage



    I also got the optimum 9X20 lathe



    Next I started building a work bench...it took me two tries to get it right






    One of the things I am doing is a R8 conversion on the mill. I bought the parts from Grizzly and luckily everything fits. I have not broken the spindle in yet and I am a little worried about getting the preload right. After reading about setting the preload on starleper's thread I was thinking I would chuck it up in the lathe, put a DTI on it, and bump the lathe tool post into it...does that sound like a good idea

    Here are some pics of the mill head while I was removing the spindle and test fitting the new one.



    To get the tach ring off I used a gear puller by pressing the spindle down and then using the quill handle to push back up.





    Here is the new R8 spindle in place



    By the way it took me 7 months to get all the parts from Grizzly to do the conversion.

    Here are some pics of where I am headed with the conversion






    Here are some pics of the stand beeing made






    I really like these casters



    Here it is with the chip pan



    I have ordered most of the electronic parts and got this breakout board off of ebay...has anyone tried this board? If it works it seems like it would be great...




    And finally here is one of the end plates Scott made for me. It turned out great. The FK pillow block fits perfectly.



    So that is all I have so far. That is a year's worth of work, so I am not moving super fast...spend more time thinking than doing.

    The next thing on my list is to lap the ways on my mill. I am not trying to start a discussion on the topic. I have done enough reading and feel good about it. Also my ball screws just came in, so I am going to try and machine the ends on. I am going to buy some stock to practice on so I don't mess it up. I got the ball screws and mounts from homeshopcnc and he said that the ball nuts are mated to the screws and he cannot guarantee the lack of backlash if I have to get new screws.

    I got the square Rex ball nuts because I do not have to modify my saddle for them to fit.

    If you guys need any pics of the mill while it is still apart let me know. By the way, in hind sight, I wish I had bought a bigger mill. The advice you here about putting most of your money on the mill from Hoss is right. Because as soon as you start using it you start wanting something bigger...

    Graham

    Similar Threads:
    Last edited by gcofieldd; 01-26-2013 at 01:20 AM.


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    Gold Member doorknob's Avatar
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    Very cool photos - looks like you've been quite busy.

    As for the milling machine stand that you built, did you weld steel backing plates onto the bottom (for attaching the casters), or did you bolt them in place? I'm not sure from the photo whether you were drilling holes for mounting the casters or you were drilling holes to mount the backing plates. What was the thickness of the material that you used for those plates?



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    Quote Originally Posted by doorknob View Post
    Very cool photos - looks like you've been quite busy.

    As for the milling machine stand that you built, did you weld steel backing plates onto the bottom (for attaching the casters), or did you bolt them in place? I'm not sure from the photo whether you were drilling holes for mounting the casters or you were drilling holes to mount the backing plates. What was the thickness of the material that you used for those plates?
    Hey doorknob, the backing plates are .25" thick steel and are welded in place. I was drilling the holes for the casters in the pictures.



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    Your chip pan looks very good, is it ready or you are going to build somekinda doors, windows etc on it? how are you going to get the chips out of it?



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    Quote Originally Posted by Madda View Post
    Your chip pan looks very good, is it ready or you are going to build somekinda doors, windows etc on it? how are you going to get the chips out of it?
    Hey Madda, the chip pan is not done. I am going to use 80/20 and frame in polycarbonate windows on the back, and left and right sides. On the front I am going to leave the top off of the 80/20 frame and put handles on the polycarbonate window so I can slide it up and take it off and put it back on. This seemed like the simplest solution.
    I came up with a lot of different ideas for the chip pan, but it was getting too complicated and expensive. As far as getting the chips out, I was just going to use a little plastic beach shovel and scoop them out—not very sexy, but it will work.
    I will model in the 80/20 frame at some point, so you can see what I am talking about. Also I will send everything out to get powder coated when I finish drilling all of the holes. The coolant tank will go on the top shelf and the drain is right above it.

    Graham



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    I did a little work this weekend. I started by trying to break in the new R8 spindle for my mill. I chucked it up in the lathe tightened up the adjuster nut at the top of the spindle and spent 10 minutes at 150 rpm, 250 rpm, and 550 rpm. At 550 rpm the spindle was getting to hot to touch.

    I assume this means I need to lighten the preload or should I just run it some more at that rpm and see if it starts to break in and cool down?

    I stopped at 550 rpm with the spindle and started to lap the ways on the mill. I started with the y axis. I used 80 grit, with no gibs and then moved to 220 grit with the gibs installed. I did not use any other grits because I did not feel there would be anymore benefit. The 220 grit left a nice finish. After lapping the y axis I defiantly notice a smoother movement with more surface area in contact. This was a very easy process. I used 3 in 1 oil with the lapping powder. Here are the pictures from the weekends work.











    I also did a little work on the one-shot-lube setup for the saddle.





    Last edited by gcofieldd; 02-11-2013 at 10:00 PM.


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    Yes your spindle is getting to hot, it should not get any hoter than *100 to *140f.

    I would back the preload off. It may be best to back it off enough that it does not cause much heat at all ( all though being tight enough not to have any clearance). Break it in all the way up to high speed (with the lighter preload), then add preload a very little bit at a time until you reach the temps I meantioned. Each time you tighten preload it will require breaking in at all speeds again. It may gain temp, but as you run it the temp drops and stabilizes. WHen it stabilzes at the right temp yuor preload shuold be good. Now you have to use good judgement when doing this, the spindle will always need to fill smooth, without to much of a tighened feeling. In other words if you tighten it once, and the heat stays low but the spindle feels to tight it may be to tight. One of the best ways of disscribing the feel is, it will feel like the spindle is being turned in super thick oil/grease. It will have a drag, but be very very smoooth. It should not take extreme force to break it loose when yuo start to turn it by hand, although it should not freewheel easy either.




    I know doing this way will be very time comsuming, but it works. Using a infrared temp gun would really help here. It is normal for it to gain temps when you tighten preload 9at each step), but not to the point it gets to hot to touch. It would also be best that after each preload ajustment, and run in is preformed, you let it cool and then run it again to record the heat and make sure nothing changes. When yuo reach the proper heat range, and it repeats the same temps after a cool down, then its time to run it at high speed for a long duration of time (maybe 1 hour) to insure all stays stable. AFter a 1 hour run in if it cools off to much then a very small bump in preload may be needed, but not much. You dont want it to run to hot, but to cool shows not enough preload. Now getting it to hot can kill bearings, so this is why its best to start low and work your way upto the right load/temp. If the bearings get hot enough to change color you may as well replace them because its to late.


    BTW, nice looking machines, good luck.


    Jess

    GOD Bless, and prayers for all.


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    Quote Originally Posted by LUCKY13 View Post
    Yes your spindle is getting to hot, it should not get any hoter than *100 to *140f.

    I would back the preload off. It may be best to back it off enough that it does not cause much heat at all ( all though being tight enough not to have any clearance). Break it in all the way up to high speed (with the lighter preload), then add preload a very little bit at a time until you reach the temps I meantioned. Each time you tighten preload it will require breaking in at all speeds again. It may gain temp, but as you run it the temp drops and stabilizes. WHen it stabilzes at the right temp yuor preload shuold be good. Now you have to use good judgement when doing this, the spindle will always need to fill smooth, without to much of a tighened feeling. In other words if you tighten it once, and the heat stays low but the spindle feels to tight it may be to tight. One of the best ways of disscribing the feel is, it will feel like the spindle is being turned in super thick oil/grease. It will have a drag, but be very very smoooth. It should not take extreme force to break it loose when yuo start to turn it by hand, although it should not freewheel easy either.




    I know doing this way will be very time comsuming, but it works. Using a infrared temp gun would really help here. It is normal for it to gain temps when you tighten preload 9at each step), but not to the point it gets to hot to touch. It would also be best that after each preload ajustment, and run in is preformed, you let it cool and then run it again to record the heat and make sure nothing changes. When yuo reach the proper heat range, and it repeats the same temps after a cool down, then its time to run it at high speed for a long duration of time (maybe 1 hour) to insure all stays stable. AFter a 1 hour run in if it cools off to much then a very small bump in preload may be needed, but not much. You dont want it to run to hot, but to cool shows not enough preload. Now getting it to hot can kill bearings, so this is why its best to start low and work your way upto the right load/temp. If the bearings get hot enough to change color you may as well replace them because its to late.


    BTW, nice looking machines, good luck.


    Jess
    Jess, that is the best explanation of setting preload I have seen on the forum. Thank you for taking the time to write that!



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    Member arizonavideo's Avatar
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    For new TRB you can set the preload by the amount of heat. They dig in a wear area when new and you don't want them to be loose for a long time or the break in area won't be even.

    It does look like they are a little tight but mine ran nearly that hot when new and took forever to break in. If you re set the preload and they run cool then they are too loose.

    TRB run hot when new.

    The spindle should be at least fairly warm to hot coffee hot after a hour or so of running at around 1K. They will break in over time.

    Check the grease while your there. A re pack is always a good idea. You want to use NLGI #2 type of grease.



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    Default sindle break in

    First, thanks arizonavideo and LUCKY13 for the posts about spindle break in.

    With your guys advice I backed the preload off a touch (at least I thought at the time) and ran the spindle for 1 hour in one direction and 30 min in the other. At the end of that the spindle was too hot to touch—I would say oven mitt hot. I left the spindle chucked up over night and this morning when I tried turning the spindle by hand it felt tighter and harder to turn, also a touch sandy inside(?) So, after doing some thinking and reading I decided to take the spindle apart and check the wear on the bearing journals.

    The first thing I realized is that to release the preload on the bearings you need to back the adjuster nut off about a quarter inch and then hit the top of the spindle with a rubber mallet. You want to be able to feel the bearings reengage when you tighten the adjuster nut and only tighten to where the spindle feels slightly sluggish to turn. Also make sure the bottom bearing is properly seated before tightening the top.

    When I took the spindle apart it looked like there was a small amount of metal dust in the grease on the bearings which might account for the sandy feeling/sound when turning the spindle. I believe what I did was over pack the bearings with grease and over tighten them.
    So, I took a napkin and wiped down the journals and rolled the bearings over the napkin and then reassembled the spindle and tightened just enough that the spindle felt slightly sluggish to turn.

    As I am writing this I am thinking that it might not be a bad idea to repack them with new grease (like arizona suggested) to completely clean out the metal dust and hopefully I do not need new bearings The journals do not look damaged…

    Here are a couple of pictures I took before my hands were covered with grease.







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    "The first thing I realized is that to release the preload on the bearings you need to back the adjuster nut off about a quarter inch and then hit the top of the spindle with a rubber mallet." - That statement would suggest you do not have the bearing properly fitted to the shaft. It should be an easy sliding fit, so that the slightest tightening of the nut will increase load on the bearing, and the slightest loosening of the nut will reduce load on the bearing. If you don't have that level of fit, it will be near impossible to properly set pre-load, as the instant you go too far, you'll have to back off completely and start all over again.

    Regards,
    Ray L.



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    Quote Originally Posted by HimyKabibble View Post
    "The first thing I realized is that to release the preload on the bearings you need to back the adjuster nut off about a quarter inch and then hit the top of the spindle with a rubber mallet." - That statement would suggest you do not have the bearing properly fitted to the shaft. It should be an easy sliding fit, so that the slightest tightening of the nut will increase load on the bearing, and the slightest loosening of the nut will reduce load on the bearing. If you don't have that level of fit, it will be near impossible to properly set pre-load, as the instant you go too far, you'll have to back off completely and start all over again.

    Regards,
    Ray L.
    Ray the bearing is a very snug sliding fit, to the point that pressure to seat the bearing has to be applied evenly or it with bind. Setting the preload has defiantly been concern that is being realized. Here are the instructions that Grizzly sent me regarding preload adjustment.


    G0704 Quill Removal & Preload Adjustment
    Quill Removal

    Unplug Machine
    Tighten Quill Lock
    Remove Motor Cover
    Remove Cap & Drawbar
    Remove Depth Stop from Quill
    Push Down on Black Cover & Remove “E”-Clip from Spindle
    Remove Black Cover & Return Spring
    Hold Onto Handle & Release Quill Lock
    Lower Handle Until Quill Clears the Headstock

    Preload Adjustment

    Loosen 2 Pinch Bolts in Spanner Nut
    Turn Nut Counter-Clockwise to Loosen
    Sharply Rap the Spindle Top with a Dead Blow Hammer to Relieve Preload
    Slowly Tighten Spanner Nut Until Backlash is Gone
    Retighten 2 Pinch Bolts in Spanner Nut



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    I am going to wait until I have my mill reassembled to mess with the spindle preload and break-in. The lathe does not like having the spindle chucked up in it. The lathe starts to vibrate periodically and also pops the fuse.

    On a better note, I was checking the run-out on my three jaw chuck and it was less than .0005. I bring it up because I am getting ready to machine my ball screws and have been worried that the run-out would not be good enough on the chuck and I would have to buy a four jaw chuck and have not been able to find an adapter for the chuck that would fit my lathe.

    In hind sight buying an Optimum mill and lathe was probably not the brightest idea. It is hard to find parts that fit the mill and you cannot buy direct from Optimum and the state side distributors are overpriced and do not carry any Optimum accessories. I got Optimum because I thought the quality would be better, but after taking the mill apart and looking at it, it is still just a Chinese made mill. I think Grizzly would have been just as good.



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    Snug sliding fit is no good, if you ever want to get those bearings set correctly. You need to "size" the shaft, so the bearing slides easily, but not so much that there's slop. You can do this easily in a lathe with abrasive cloth - you probably only need to take it down a tenth or two.

    Regards,
    Ray L.



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    Default Parts on their way

    Here is a pic of some x-axis and y-axis parts Scott from Bench Top Precision made for me. They are in the mail now.





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    Registered Mad Welder's Avatar
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    Yeppee another BF20 build.......post plenty of pics

    Eoin


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    I will Mad Welder Thanks for posting



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    Default Still plugging along

    Hey guys, it has been about three weeks, so I thought I would post some pictures of the progress I have made.

    I got the stand and the chip tray powder coated, got parts in from Scott, and have been trying to figure out how everything wires up.

    I noticed that some people make control panels with manual controls and some people just use the manual inputs from Mach 3. Does the benifit out weight the cost of having a manual contol panel? It looks like Dave Decaussin just uses a touch screen on his UMC-10.

    If I do make a control panel these are the functions I think I need:

    E-Stop
    Cycle Start
    Cycle Stop/Pause

    Spindle Manual/Auto
    Spindle Start/Stop
    Spindle Forward/Reverse
    Variable Speed Pot
    Coolant On/Off/Auto
    Key Lockout
    Maybe a light switch and tool change button...

    Here are the pics:











    Currently the X and Y axis ballscrews are out for machining, I am working on the Z axis, I am working on the control box and possbly the control panel.



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    You'll probably want a MPG as well for jogging.



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    Quote Originally Posted by gcofieldd View Post
    I found a Baldor motor (VM3550) which looks promising because of its small diameter, but it is not rated for inverter use. Has anyone used a regular motor with a VFD?
    I'm running a "std" 1hp 3 phase motor with VFD on my lathe and have had no problem with heat and it runs very smooth at all RPM. Price was my decision maker...at my hobby level it doesn't run every day but when it does I usually run it for 6-8 hrs.

    Great job on the build log,I will be watching.



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