Member postings for Dr_GMJN

Thanks Dave. I think in the image, the brass casting is displaced to the left slightly, and the depth of the slot is such that the radius wouldn't be concentric even if the brass was central. In other words the slot isn't quite deep enough.

There's no doubt though that there isn't a smooth transition from flank to radius - at least on the resulting cut in aluminium. I'll try it on some other material if I get chance.

Thanks Jason. I would have taken the top end to bits myself, but since I had nothing but an exploded diagram I didn't want to do anything stupid. It was always going to be something loose or a duff bearing.

I spoke to Ketan this afternoon about the cutter, and he assured me it was the correct geometry.

I might do a quick test on a differnent material later on, but since I should have ordered something smaller it doesn't really matter that much.

So Ketan from ARC gave me a call this afternoon, and we quickly sorted the issue. On removing the motor (to test it for noise), it became obvious what the problem was: the countersunlk pulley retaining screw had loosened, allowing the thick washer behind it to spin freely. This was making the dry bearing type noise after the spindle had stopped, and intermittently when running. The other, more worrying noise, was probably casued by the screw head contacting the top casing and making a squealing noise. It was also intermittent because on contact with the case, it partially screwed itself back up into the shaft, out of contact, until vibration caused it to run back down.

Removal of the top casing showed no excessive dust from the belt, or swarf, and the spindle turned freely.

So it's now back in one piece (with some Loctite) and running quietly again. Thanks Ketan!

Thanks Martin, but there is no quill extension to lock on the SX2P. As I said, the head (z-axis) was locked, as was the x-axis.

I was using an ER25/R8 collet chuck, with the cutter inserted as far as possible. The workpiece was in a vice, so head height was also minimised.

Spindle bearings? No idea. There is no discernable play in the spindle, but I think there could be an issue with them judging by the noises now coming from that area. Something tells me it's not that though. It's not rough, but I think rather some plastic part is rubbing somewhere.

I can't find any strip-down guides to the SX2P, but I'm sure it's not rocket science. Since it's only been used a few times, I've contacted ARC, so we'll see what they say.

I think a Bull Nose has a flat end with radiussed corners?

I ordered a Ball Nose, and that's what I was sent according to the box - I assume I ordered the right thing?

Either way, surely the end radii should be tangential to the face and flank?

I've emailed ARC and attached a couple of video clips so we will see what they say.

I suspect it's a bearing, or something that's fallen off a bearing such as a sealing ring. It's certainly not right though.

I'll try to get a decent picture, but with all the vibration and cack-handedness in the world, I doubt I could have ever got a non-tangential slot edge from a tangentially edged cutter?

My assumption too.

In fact even if it was correct, the brass insert isn't 7/16", it's smaller, so the fit would have been sloppy anyway. I should have checked before buying. Anyway, I'm glad I did a test on scrap - my casting is intact...for now.

No, it was 7/16" as per the drawing. The brass is slightly smaller (should have checked I guess) and would approximate with slight clearance to 11mm diameter.

As noted, the critical dimension is probably from the machined sole plate top, to the bearing axis. Some clearance at the base of the radius might be beneficial.

Jason,

My plan was to align the sole plate centrally - by eye - on the box bed - after all I want as equal gaps as possible all around, and I assume doing this by eye on castings like these is as good as any other method? I might put a few spots of pva on the joint so I can move them around together for aligning the sole plate on the mill table. I'll confirm I've got a best fit in x & y by putting a pointer in the chuck and moving it along the casting edges and bearing features, then center it to 0,0 in the middle of the piece using the DRO's. Then I can take co-ordinates for drilling the corner holes.

Then clamp together and drill the 7BA tapping holes straight through both parts.

Then open up the sole plate holes only to 7BA clearance, and spot-face. I'll use the head vertical hard stop to make sure there are no screw ups with depth.

Then remove the base and tap the box bed.

I think I may need to displace the holes outwards slightly to get a clean spot face, but If I note the drilling co-ordinates from the DRO's it shouldn't be an issue.

Cheers.

Yes I did, it's brand new pretty much. I'll end up stripping it, but will email ARC first with a video and see what they say. I'm not sending it back - way too much hassle, plus I've modded it with DRO's etc.

Cheers.

Teflon spray squirted into the bearing pockets. I realise the bearings are sealed, but it sounds like something else spinning around on the shaft. I was hoping some of the spray might find its way into the head and at least change the noise.

Thanks Paul, it's different from the SX3.

Thanks All.

JasonB - I think I ordered the cutters before I'd appeciated the different grades. Certainly before ordering the carbide inserts form Cutwel.

I think an 11mm diameter slot drill would be a good size for the brass.

I like the idea of plunging the cutter from the top (slot drill?), or incrementing it in from the side.

Cheers.

So the more I use the SX2P, the more I'm getting used to its foibles. This evening though, it started chirping. Like a bird. It's coming from the spindle I think. It sounds almost like hard plastic catching on metal. Also, when I switch the power off, there's a strange noise after the over-run, like a dry ball race when you spin it (even though the spindle itself is stopped). I tried squirting some lube in the top and bottom, but it had no effect. I'm kind of reluctant to start stripping the head, because I'm already spending more time on chasing various issues than machining parts.

Has anyone else noticed this on an SX2P, or have an idea of what it might be?

Thanks.

So I got the new end mills from ARC today. Again, face milling is fine, but there's no way side milling is right. even a 0.1mm cut in 15mm thick steel is hopeless - noise, vibration, terrible surface finish. I tried it again with a Sandvik cutter, and it's the same. I'm wondering if it's the material I'm trying to cut. Pretty sure it's mild steel - I've made 4 vice clamps now, with no real issues with fly cutting, face milling or drilling. As soon as I switch to side milling, there's just no way it's having it. All axes are locked apart from, in this case, y. Tried changind speeds and feed rates, to no avail.

Thanks.

I just started building the Stuart 10V, and I bought a 7/16" (0.4375" Ball Nose end mill, with the intention of using it to make the 7/16" wide slots for the main bearings, as specified on the drawing. The brass casting supplied is actually a bit smaller than 7/16", at 0.4285" wide. The cutter itself measures approx. 0.4350" according to my verniers, and made the same width slot in some aluminium I used as a test:



However, it appears that the radus of the ball end of the cutter is not tangential to the flanks:



It's quite prononced. I cut the test slot to the correct depth, and this is the fit I get with the brass:



Although it's not necessary for a perfect fit, I Think I could have done significantly better with a file.

Apart from "so use a file" - any comments on the best way of doing this? I'd like to use the mill seeing as I've got it, and assumed a 7/16" Ball Nose cutter would have at least given me the right shape.

Second question on the bearings: my plan is to machine them from the brass casting in the lathe, drill out until I can use a reamer, then fit them to the sole plate, aligning them with a suitable dowel (maybe the appropriate drill bit). Then mount on an angle plate on the mill, align with the drill again, and ream them both at the same time. Is this a sound method?

Thanks!

Finally took the plunge and machined my first casting. Nothing spectacular, but it feels like a big step for me. I opted to use the fly cutter with an insert for cast iron, mainly because it's by far the best method I've used for getting a good finish. I used my fixture plate for one side, and the remaining two vice clamps (finished this evening) for the other. There's no height specified on the drawing, so I just did the mimimum clean-up. I think the different colours through the wall must be something to do with how the metal cooled:

I should have posted this here I guess, just to say what I did as a result of the advice given (it's also in another thread). I got a selection of 4 types of insert from Cutwel. Ordered 16:30 yesterday, arrived this morning. DCMT, DCGT, 0.2mm and 0.8mm nose radius, some for cast iron, some for non-ferrous and others for steel. There was an online chat thing, so I was able to confirm I was getting the best inserts for my tools and what I wanted to do:

So the small fly cutter holder arrived today. I put my Sandvik 8mm left hand tool holder in it, fitted with a DCMT 070208 insert for steel, and had a go at fly cutting for the first time. Must say I was really happy with the results, finally a bit of progress. Workpiece was the same mild steel I've been using for the vice clamps. I went up to 0.5 mm cut depth with no issues.





The only slight problem was vibration due to the tool holder being long. I ground it down a bit and that resolved that. The grub screws in the holder appear to be made of cheese, so having got the tool well and truly stuck, I spent a good 30 minutes drilling them out and replacing with caphead screws, which was fun.

Missed the postman due to work, so the milling cutter test will have to wait, but in the meantime, for the 10V castings, what do folks recommend for facing: milling or fly cutting? I did get some DCMT070208 inserts for iron too.

Thanks.

As an addendum to this, I'm a bit unsure as to feed rates and spindle speeds. Pretty much everything within reason worked without any complaint from the machine. I got the impression I might have been running at too high an rpm though, becasue the chips appear to be blued by heat.

Still, I faced my remaining vice blocks, and got much better surface finish than milling, and parallel over 25mm x 40mm to within 0.0006" according to a my micrometer, over an average of 5 measurements. Sorry to mix units!