Chester 20v and G0704 comparison


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Thread: Chester 20v and G0704 comparison

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    Default Chester 20v and G0704 comparison

    After reading the mammouth 200 page thread from Hoss (good work dude), I decided to get one of the BF20 clones. Here in the UK I bought a Chester Champion 20vs for around £850 delivered.
    I got the thing out of the crate today and on to the bench.
    First job was the three-bolt mod, which interestingly enough, needed no grinding down of the extra bolts, they were a perfect fit.
    A couple of other things I have noticed so far is that I am hoping have a full 200mm of travel on the Y-axis if I remove the bellows, and also that the motor is 850watt. One more thing is the quill travel is 52mm rather than the quoted 42mm on the Chester website.
    I will update this thread with more specs as I strip the machien down.

    Similar Threads:
    Attached Thumbnails Attached Thumbnails Chester 20v and G0704 comparison-mill-jpg   Chester 20v and G0704 comparison-motor-jpg   Chester 20v and G0704 comparison-200mm-jpg  


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    I took the spindle out today, not too difficult, but it is a little diferent to the G0704. Surrounding the drawbar collar is a steel collar, which seems to be integral to the gear-drive. Once the spindle was removed I had a peek down into the hole, and looks as though this collar is joined to the splined section which is driven by the gears, and in turn, drives the spindle. This should make the belt-drive conversion easy, since I can just bolt the pulley straight onto this collar.
    Anyhow, there are some photos of this detail below, and a piccy of the litle light which is up beneath the head too. Unfortunatley it only worked for a few seconds then blew the bulb.

    The spindle bearings required for high-speed will be two of the 7005B variety, which I cannot find in the UK so will need to order from VXB.com These are the same size as thr G0704 upper bearing.

    I have measured up for the ballscrews today, so once they are drawn up, I will order from linearmotionbearings2008 on ebay. He seems to be 70% cheaper than any UK store, unless anyone can tell me otherwise!

    Attached Thumbnails Attached Thumbnails Chester 20v and G0704 comparison-collar-jpg   Chester 20v and G0704 comparison-remove_quill-jpg   Chester 20v and G0704 comparison-lamp-jpg   Chester 20v and G0704 comparison-spline-jpg  



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    Hi GarageCNC. i look forward to seeing your project unfold. Il be buying a BF20 type machine myself to convery to cnc. I have been looking at the one from Amadeal but they are out of stock atm. did you get the R8 spindal or the 3 morse? I have a Champion mill from chester but it isnt a very good candidate for a cnc conversion (it has a round colum) and the spindel quill is a sloppy fit even when locked, hows the fit of the 20VS quill?


    regards
    Simon



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    If you are looking at steppers i would go for the g540 setup from keiling it is all that is required when using ballscrews. i have an spg version and get 1500mm/m on all axis and can plough through anything at a reasonable speed with good acceleration.



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    Simon, I have an MT2 spindlem which is a shame really since I cannot use the Tormach quick change tooling system. Having said that, I already have quite a bit of tooling which will fit.
    The spindlke has no noticable slop, although I have not done any test cuts yet.

    Fragger, I read your article a couple of times already, did your mill have the steel collar covering the drawbar reatainer? I see you have already done the belt drive mod, I cant wait to reduce the noise from the grinding gears!
    I am aware of the Keling setup, those digital drivers sound excellent. Unfortunately I have already got a set of 3.1Nm steppers with 4.2A drivers from Motion Control Products from an old mill. I will give them a whirl first, and see how I get on. Shame I gotta wait 3-4 weeks to get ball screws from China



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    Does MT collets really prevent you from using TTS? I thought all you need is a 3/4" collet as long as there a spindle nose for the tool to index against? Does the MT collet system preclude that?


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    MT2 collets only go up to 5/8, MT3 will go up to 3/4 for TTS.
    Hoss

    [URL]http://www.hossmachine.info[/URL] - Gosh, you've... really got some nice toys here. - Roy Batty -- [URL]http://www.g0704.com[/URL] - [url]http://www.bf20.com[/url] - [URL]http://www.g0602.com[/URL]


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    Just a quicky, I found a supplier of the 7005B bearings in the UK, although they only sell shielded ones. Easy enough to remove the seals though. Check out "Simply Bearings" Here



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    Got the bearings this morning and had a go at a couple of spacers on the lathe. The pic below shows the completed spacers, the one with the step is for the top bearing, so when the lock-nut is tightened, it will put pressure on the inner race, and will pre-load the angular contact bearings.

    Things did not go entirely to plan...I ended up removing the lower spacer and using it beneath the upper bearing with the upper bearing now in a sandwich between a flat spacer and the stepped one. Anyway, it is all back together and runs ok, just need to do the break-in now and keep on the tightness of the spindle. Just out of interest, how do you know how tight it should be? I assume the temperatures will be the giveaway if the pre-load is too tight?

    Attached Thumbnails Attached Thumbnails Chester 20v and G0704 comparison-bearings-jpg  


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    why are you changing the bearings?

    i have been running the tapper rollers up to 4000rpm with no problems, are you planning on going much faster than that?



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    Looking at 6000 rpm, (Sssh, sometimes I cut timber on the mill)



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    the stated rating on the taper roller bearings are supposed to go up to 6000 with grease but that also dependent on preload. when i run my mill at 6000 there was alot of heat build up. so i think it is a worth while thing to do but i took the veiw that i can change them later.



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Chester 20v and G0704 comparison

Chester 20v and G0704 comparison