New Chucks for the Proxxon FD150

[Roger B]

When I got my FD150 the supplied 3 jaw sc chuck, although inside the manufactures specification, did not meet my requirements. 0.15mm runout at 20mm was not quite good enough. I looked at what other small chucks were available and the Sherline ones seemed to offer an improvement at a reasonable price, suggesting 3 thou (~0.08mm) runout. As they offered M12 x 1 and M14 x 1 versions I asked if they would offer M16 x 1 to suit the Proxxon but the answer was no.
I ordered M12 x 1 versions of the 3 jaw sc and 4 jaw independent chucks and after quite  a few weeks they arrived. From left to right are the two Sherline chucks, the original Proxxon chuck and a rather cheap and unpleasant 4 jaw chuck from RC.

I turned up a 17.98 and a 17.99mm plug gauge to match the alignment recess for the Proxxon.

The chucks were dismantled, set up in the 4 jaw independent chuck on my Hobbymat and initially bored out to 15.0mm for the thread and to set a reference for the alignment recess. The recess was then bored to suit the plug gauge, guided by the DTI on the cross slide.

[Roger B]

The M16 x 1 thread was started with single point cutting to ensure it was true to the bore and finished with a tap set to get the correct profile and fit. The chucks were then reassembled and tried. Using a piece of 8mm silver steel I got a run out from the 3 jaw of about 0.08mm at 40mm , so about as Sherline suggest and much better that the Proxxon spec. The 4 jaw looks ok but I am not quite sure what I can check that is also not affected by the lathe slides and ways  It does give me a capability that was not available from Proxxon.

<a href="https://www.youtube.com/watch?v=glY4Au2EOtc" target="_blank">http://www.youtube.com/watch?v=glY4Au2EOtc</a>

[steamer]

Thanks for posting that!   It's good to see that the chuck body will open up to 18 mm    I'll keep that in mind as I use these chucks for small work in my SB.   I have them on 3C shanks for use in the collet holder and 3C indexer I have.

I really want to turn a register on the chuck bodies to make to the adapters to improve the repeatability and overall accuracy.    Looks like I can!   

Dave

[Roger B]

According to the Sherline website the standard thread is 3/4 - 16 so I decided 18mm would be no problem. I chose the M12 x 1 version to reduce any influence boring out the thread may have. The metal Sherline uses machines nicely with a SS insert at 1000rpm. The thread was cut at 250 rpm as I was too lazy to set up the slow speed belt.

[Jo]

They will make a big difference 

I have a Sherline four jaw self centring I fitted to Little C which is very nice. As for that four jaw independent chuck from RC - I've seen that brand at shows and the only thing they are good for is doorstops 

Jo

[joeiznogood]

This is awesome. I hope to do the same, since I am very disappointed that Proxxon only sells a self-centering 4 jaw chuck... Really annoying they chose a clearly non-standard thread hoping for M16x1 rather than M12 or M14.

Sent from my MAR-LX1A using Tapatalk

[joeiznogood]

Do you think it would be viable to turn a thread converter instead? A piece that screws on the M16 thread and then reduces to a M14 thread?

My problem is that I /only/ have the FD150 and I am not sure how well that would handle boring out whatever steel the chucks are made of.

Sent from my MAR-LX1A using Tapatalk

[Jasonb]

A step down adaptor will move the chuck further from the headstock bearings so not a good solution.

[Roger B]

The FD 150 will happily bore out the Sherline chucks but there are two problems. 1) How will you hold the chucks to bore them? 2) How will you cut the thread? I bored mine out at 1000rpm taking shallow cuts, no problem with the Proxxon if you can hold them, possibly reversed onto a sleeve on the nose thread. I then started the thread by screw cutting with a single point tool (not possible on the Proxxon) and then finished with M16x1 taps to get the correct profile. You could tap the thread directly but it will be difficult to keep it square and will require a high torque.

I think the choice of M16x1 is due to the ER11 collets. The standard collet nut for ER11 appears to be M14x0.75 so I could see people trying to fit this onto a M14x1 nose and damaging both.

[joeiznogood]

Thanks a lot for your answer, Roger.

The FD 150 will happily bore out the Sherline chucks but there are two problems. 1) How will you hold the chucks to bore them? 2) How will you cut the thread? I bored mine out at 1000rpm taking shallow cuts, no problem with the Proxxon if you can hold them, possibly reversed onto a sleeve on the nose thread.

I am glad to hear that the Proxxon should be able to bore the chucks without issue! Mounting it in reverse onto a sleeve would make sense for the boring operation.

I then started the thread by screw cutting with a single point tool (not possible on the Proxxon) and then finished with M16x1 taps to get the correct profile. You could tap the thread directly but it will be difficult to keep it square and will require a high torque.

Riffing on the mounting idea above, could I possibly mount the 4 jaw chuck onto the tailstock spindle and the M16 tap in the Proxxon 3 jaw chuck? Squaring things up as good as possible with a dial indicator. Wouldn't provide torque though, since I would be doing it by hand.

I think the choice of M16x1 is due to the ER11 collets. The standard collet nut for ER11 appears to be M14x0.75 so I could see people trying to fit this onto a M14x1 nose and damaging both.

That makes sense with respect to the thread mismatch with a standard ER11 collet nut. Still unfortunate though! Because it seems M12x1 and M14x1 chucks are readily available many places.

Sent from my MAR-LX1A using Tapatalk

[joeiznogood]

A step down adaptor will move the chuck further from the headstock bearings so not a good solution.

Right of course. So that would mean larger forces on the bearings?

Sent from my MAR-LX1A using Tapatalk