Hi everyone.
I have a XJ25 mill which I got from Amadeal. Its not a bad machine.

The gears in the gearbox are Plastic (maybe Delrin) and as such I have stripped a couple of the teeth off. Luckily, I had a spare set. I would like to make a set out of Brass for a bit better longevity but I am not sure what cutter is required. It looks like a 1.5mm module gear tooth but I am not 100% sure. Is there anyone out there that has made a new set of gears and the knows the correct cutter required.

Failing that, has anyone come up with a way of converting the machine to belt drive?

Any info gratefully received.

Cheers

Paul

Not sure on what cutters to use, but maybe Aluminum might be better? I just find brass very soft, I could be wrong though.

-Speed

Aluminium? Blimey, that's softer than Brass.
I was going to use very hard Brass. It has fairly good wear properties but Aluminium is way to soft unless you get the heat treatable stuff.

Paul.

I have the XJ20 (slightly smaller then the 25) and when I cleaned the mill after delivery I took note of how fragile the gears looked. I make a real effort not to stress them as much as possible, but I'm sure one day they will go. The question is does that save the machine from other failure?

A slight side note, hope you don't mind as I'm not sure how many people have these models, how good is your quill for wobble. I can really see mine move with regard to the casing hole if I lower it a bit and pull on the chuck. Is there any way to tighten it up or is it going to require some creative thinking?

Yeh, my quill is also sloppy. I did get on to Hugh about it and he sent me another head unit which was better but the casting was terrible with blow holes but the quill fit was much better.

I have decided though that as I had fettled my original head unit that I would get the quill hard chromed to build it up and then ground to fit. That way it should be a perfectly usable unit. Not cheap though.

Apart from that it is not a bad little mill. I have also put a coolant system on.

DRO next.

Thanks for the reply. I think the fantasy accuracy report sheet would be interesting to compare against what I actually measure. I'm a bit worried to do it as it will probably blow the needle off my DTI.

I've yet to speak to Hugh about and that's mainly because I doubt there's much he can do about it in real terms. I'll have a look at stripping it down on the weekend to see what's what.

If you look at Arc Euro trade I'm sure I've seen advertised steel gears for these, I've stripped the low gear but I'm going to belt drive because of the noise.

AGA-man

Thanks for your reply. I will have a look at their site.

How are you going about your belt drive conversion. I would like to do the same because of the noise. Only way I can see of doing it is to make a new quill housing to enable the fitment of pulley(s) on the end. Are you proposing to use a timing belt with teeth or V belt? The timing belts supplied by Technobots seem ideal.

Cheers

Paul

I have bought timing pulleys from technobots, and machined them but the could do with larger pulley's(and the larger one made of steel)and technobots only do alloy ones, look at fignoggle designs. Let me know if you find another source for belts and pulleys of this size.

Have you guys thought about doing a belt conversion like x-2 owners have done. Seems to be the easy and machine safe way to go. By the way the xj 25 is one of my fav mini mills. They always looked like they were well made. Surprised to hear about the slop in the quill which sound like bearing replacement is needed.

AGA-man

http://www.hpcgears.com/sitemap.htm do timing pulleys up to 400mm dia and more and varying belt widths.

Is there any chance of some pictures as to how you mounted your pulleys on the XJ25. Any info would be appreciated. Are you just relying on one ratio or are you using a step pulley arangement.

As I said earlier, I am a bit stuffed as to how to mount the pulley on the quill shaft.

ZipSnipe.

Its not the bearings that are the problem. The whole quill column is basically running to big a clearance in the head casting. On my machine the quill column is 8 thou smaller than the machined bore in the head casting and as a result wobbles like hell. It should be about 1 thou all the way round for a nice slide fit. I am going to get the quill column hard chromed to build it up and then have it ground to fit after I have the head jig bored to make sure it is fully round and parallel.

I have seen the belt drives for the X3 machines but I think it still uses an intermediate shaft that drive the quill shaft via a gear. The gears on the XJ25 are plastic and are crap. The idea is to belt drive the quill shaft using no gears at all and so make it quiet.

Cheers

Paul

Hi,

Have you guys stripped the spindle or at least removed the bearing cover and checked for chips?

I noticed that with the quill locked I was still getting movement on a test bar. The long and short of it was there was no preload on the roller bearings. So I stripped it down; lots of chips in there and while turning the spindle by hand it would lock up due to at least one of the chips trapped between the rollers. I’ve now washed out the spindle, reapplied grease, preloaded the bearings and reassembled.

If I had not had done this it would have given me nothing but trouble chatter, broken gears and very likely broken tools.

As for the plastic gears; I do plan in the future to convert to belt but for now they will have to do.

The quill on my XJ20 is piss poor also but as I have it locked for CNC use it not to much of a problem but may short it if I feel the need to use it. On this subject have you guys considered Moglice?

John

Hi John.
I too had trouble with the spindle. I ended stripping the whole mill, cleaning everything and got about a handful of swarf out in the process. It seems to be the norm with chinese tools.

I see you too are thinking about belt drive but has anyone actually got any ideas how to do it. I got the impression AgaMan has but he seems reluctant to share. I think a new drive shaft will be required but it would need broaching for the spline of the quill shaft.

I am at a loss as how to convert to belt drive so if any one has and is willing to share it please let me know.

Many thanks
Merry Xmas
Paul.

I plan to take some sizes from the plastic cogs in the very near future to see if I can find some steel replacements. When I do that I will work out what’s needed/will work for a belt conversion. If you get there before me give me a shout and I will do the same and post here.

Have a good one,:)
John