bf20 spindle removal

[chalky]

Has anyone ever removed the spindle cartridge from a bf20, or one of the equivalent mills? I assume that you push down on the return spring retaining bush and remove the c-washer to free up the splined end of the quill? Any guidance much appreciated.

[iGG1e]

Yes that's all you have to do after taking the quill feed mechanism off. From memory there is no quill stop, so it'll just drop out when you remove the C washer.

[chalky]

Thanks for the help iGG1e. Can you just push the sleeve against the spring by hand or does it require a bit more force? Have you done much with your bf20 in the way of projects or modifications? There aren't so many bf20 and clones about in the uk so its good to come across another owner. The bf20 is extremely popular in germany and there is plenty of discussion on their forums - unfortunately my german is a bit rudimentary

[iGG1e]

Been quite a few months since I took it apart and my focus has been on taking apart/modifying my CNC mill, so the memory of it is a bit hazy. I think it was easy enough to push by hand, but I possibly used something on the edge to protect my hand. You don't have to move it down far to release the pressure on the C clip to extract it. I certainly don't remember (I've actually taken it out a few times) ever struggling that much.

As for modifications, nothing other than what I needed to do to make it work properly. For some reason it decided to chew the brass gear on the motor and no matter how I aligned it, the replacement was heading the same way. A cautionary note, there appears to be a couple of variations of gears, different tooth angles and number of teeth. I decided to get rid of their gears and I replaced the brass motor gear with a straight cut one and the large steel gear I had to replace with a plastic one as that was all I could get hold of at the time. So far this has held up surprisingly well.

Oh and the speed control pot developed a nasty hole in the middle of the range that would cause the motor to pulse. I replaced it with one from Farnell.

Overall it has helped me do things I previously couldn't and even with the CNC mill, I really wouldn't want to be without it...sometimes setting up the CNC just seems like too much effort.

[chalky]

Thanks for the heads up on the minor niggles. I haven't had any problems so far and am quite pleased with the way the mill chews through steel. Which variant of the bf20 do you have? I got a Weiss wmd25lv from Amadeal but Chester and Warco sell essentially the same mill under different names. The basic machine has evolved a bit over the last few years as well. Discovered recently that the Optimum bf20s use a chinese speed controller whereas the Weiss machines use the KB Electronics controller from the US ( more reliable ). Incidentally the reason for the interest in the spindle is not because I've broken it (yet!) but because I'm looking at the possibility of a belt drive conversion. Its a bit trickier than on the Sieg X2 and X3 because the geared connection to the quill is inside the head casting. The wmd25 has a spindle speed readout and the outer gearshaft protrudes a little further up from the bearing than on the standard model - maybe just enough to get a pulley on it, although I'd then have to move the interrupter wheel and led/phototransistor

[iGG1e]

Mine is the variant without the speed display, but supposedly with the US control board. You're right about the lack of space for a belt drive conversion. It does look a tricky one to convert if you want to keep the high/low gear selection.

I must check out some of those German forums to see what mods have been done. There is a user on here (Swedish I think) that I seem to recall used the mill as the basis for a really neat CNC conversion. Designed a new head with high speed spindle or something along those lines.

[chalky]

I probably won't bother with the high/low gear but drive the spindle directly from the motor using a couple of timing pulleys and a 5mm pitch timing belt. I think there is enough of the outer gearshaft exposed at the top to get a pulley on. I'll have to relocate the toothed disc for the speed readout but that should be fairly straightforward. I think I'd be happy enough with a single pair of pulleys and the variable speed drive. A double pulley dual speed system would be possible but it would probably mean machining a new motor mounting plate.

[BJoz]

Hi Guys,

I hope this thread is not dead.

I'm pulling apart my BF20 head to give the internals a good 'grease & oil change', and I'm having problems getting the spindle shaft assembly out. It's a fairly new machine, but I get some strange noises coming from the head, and the thing runs pretty hot after only 10 mins or so running time. And I mean h-o-t - almost hard to touch with a naked hand.

My model is a 'Top Tech' BF20 Vario from Standaco here in Victoria, Australia. The 'user manual' leaves a bit to be desired, and apart from an exploded parts diagram, I don't have a lot to go on.

The spindle assembly seems to be spring loaded, and I'm guessing to get it out, I have to somehow get the 'C-Clip' off the top of the splined/threaded shaft. This seems to be a Catch-22 - the metal colar at the top (which I presumes houses the spring underneath) is cup-shaped and has a lip on it. The C-Clip sits in a milled groove on the shaft itself and within the cup, so there's no way I can prise it back far enough to free it from the retaining groove, nor can I expand it enough to free the groove and lift it over the top. The lip on the retaining cup prevents both the backward movement and the expansion of the C-Clip.

How do you get the darn thing off? And is something likely to go "ping" and fly across the garage when I finally do get it off, given that that spring has a fair bit of pull on it??

Any help would be much appreciated.

BJ

[iGG1e]

BJ...let your inner animal out!

Unless it is different in some way from mine, you need to press down hard on the spring loaded collar, then you can slip the C washer out. The washer has no other retention mechanism other than spring pressure and the cup lip.

Have another crack at it.

[BJoz]

Mate - I pressed down with every ounce of energy I had left - all that happened is that the whole spindle kept moving down inside the head.

I've got the whole head off now - on a wooden block. I'm thinking that the spline itself maybe burred-over, and that it's jagging on something up the top there

I'll have another go at it Maybe a 10lb sledge and an oversized socket will help persuade it... ??

BJ

[BJoz]

Update: I had a quick squiz before I left for work this morning, and ~voila~ - I can see how to get it off now. On my model mill, the lip of the 'cup' is really thin and quite sharp, and sits only a mm or so above the C-Clip. Sooo... when I was pushing down on it with the head still attached to the mill, all I could feel was the whole assembly pushing down against the spring tension through the head.

Even with the head off and resting on a block of wood, it's barely imperceptible that the cup itself moves down and away from the C-Clip. But, anyways, I reckon I've got it sussed now

Can anyone recommend a good quality grease to use on the gears, bearings and other running-gear? The stuff that has been used on the mill ex-factory is this translucent lime-green goop that is everywhere inside the head except on the gears themselves - where it should be. I suspect that that's where half my noise and excess heat are coming from.

Once I've got all the shafts out, I think I'll head to the bearing shop up the road and replace all bearings with some decent (SKF etc?) ones - a bit of 'long-term insurance' ...

BJ

[BJoz]

Update 2: Already tried to post this once, but good ole Windows lost the post.

Opened the collar up to check the bearings - no surprises really. There's a pair of el-cheapo 32005 roller bearing in there instead of angular contact 7005AC/P5's running as singles - they don't need to be a matched back-to-back pair as they are about 2 inches apart).

What should I do? Opt for another pair of 32005's at $20 each, or go for the 7005's at 165 bucks a pop?