ER32 Collet Chuck for Proxxon PD 400

[Wongster]

I completed the recess today. It is a little tight that I wasn't able to remove the gauge after tapping it in with my hand. It wasn't that it is too small but I wasn't able to get it to seat due to air pocket within. Once in, it refused to come out...

Allen key was used to carefully pry it out.

I started by centre drilling and drill to about 4mm deep with a 5mm drill. An endmill was used so that the inside of the hole is flat. I felt silly after that as it will be bored away later... The Sherline boring bar was used to enlarge the shallow hole bit by bit till it reached about 63mm in diameter. No reason for that diameter but wanted to leave some "meat" in case of error. Unless I know of a way to add metal back...







After I get to about 63mm, I started enlarging the recess further by boring the side wall of the recess bit by bit till the gauge fits. The gauge stuck in the recess...





The "floor" of the recess was then clean off as best as I could but I couldn't make it shine like what Rob and Dave did.

I'm letting it cool off right now and will test with the gauge again to see if I need to open it up a little more. Will sand it then using the boring bar if it need be.

Update:
It still fits but the air pocket still prevent the gauge from sitting in properly. Should I do anything more? Also, I just remembered that I forgot to scribe the PCD for the bolt holes!!! All is not lost, me think. I've on order, from Little Machine Shop in US, a set of M6 Transfer Screws. The recess will help to locate the collet chuck while I tapped the part to transfer the hole locations.

Regards,
Wong

[Wongster]

I was rather curious to find out if the recess fits the bore on the spindle flange. Went back to the shop and take everything off and fit the work.

It seems to fit nicely...



Look ma, no hands!



Pushing the flange of the chuck to be against the flange with one hand, I started rocking the piece. I can feel slight movement and some knocking sound at certain point... boy am I disappointed...

I put on the 3 jaw chuck (without the bolts) and did the same. The slight movements and a little knocking sound is also there.

Do I declare my work so far resident of the scrap bin? Any remedy?

Regards,
Wong

[RobWilson]

Hi Wong


Don,t give up first off see below .


a small bur could be causing the rock .




" I've on order, from Little Machine Shop in US, a set of M6 Transfer Screws"
Just grip a 6mm bolt in the lathe chuck.Turn a point on the end.



file two flats on the end .


and cut off .


screw into job using pointy nose pliers so that the point is just proud ,



fit parts together and give a good blow with a soft hammer .



Rob

[DaveH]

Wong,

No definitely not for the scrap bin.

It is looking good, you have nearly done the difficult bit and if your 3 jaw chuck does the same rocking may be like Rob has said there is a slight "bur" on the spindle flange.

Just check the spindle flange, carefully, very carefully "wipe" it with some very fine emery paper, especially any edges. Also check for "burs" around the holes.

Follow Rob's suggestions as well and it is going to come out perfect

DaveH

[Wongster]

Hello Rob,

Thanks for the trouble with the pics. I used the wrong word to describe the problem. The "rocking" feel is not due to the 2 surfaces not sitting properly but I think I've the recess a little too big. I was thinking about it while I was out - The aluminium gauge I did has to be pushed into the recess at the back of the 4 jaw chuck to seat. The fit is rather tight. So it could be that the gauge is a little bigger than it needs to be. I almost ran into my shop when I got home (just got home less than 5 mins ago) to confirm my suspicion; indeed, the gauge is 0.02mm bigger than the registration boss on the spindle flange. The boss measures 69.99mm but the gauge 70.01mm. I hope the 0.02mm wouldn't cause too much problem.

I like the transfer screws you did. I read Bob Warfield's blog on the making of his transfer screws. Didn't quite understand how he did the point which has smaller base.



I only know how to make it with base like what you shown in your pic. But the flats at the 2 sides is a

What were you doing in the pics? The piece looks like a saddle or compound slide.

Regards,
Wong

[Wongster]

Hello Dave,

I'll continue with the work. Thanks for the encouragement.

It will be completed to get a good feel of how the whole project is to be completed and if I need to redo the piece, at least I have some experience in the bag.

Regards,
Wong

[DaveH]

Wong,

This chuck should be fine the .02mm (.0008") isn't a major issue.

Like Rob said earlier when it is placed on the lathe spindle flange you will mark it (centre punch), and always pull the chuck towards you. This will make sure the chuck is always placed on the lathe spindle in the correct and most accurate position. Just eliminating some of the .02mm

Likewise this will be the same position the chuck is fixed and positioned to the spindle flange during the rest of it's manufacture


DaveH

[RobWilson]

(05-20-2012, 08:15 AM)Wongster Wrote: What were you doing in the pics? The piece looks like a saddle or compound slide.

Regards,
Wong

Hi Wong

Very close mate ,,,, new table ends for the 626 mill .


As Dave said ,,,,,,,, i think your part will turn out fine ,,, just get in the habit of de-burring your parts ,,, hang in there


Rob

[EdK]

Rob,

Did you cast that new table end? What is its purpose? It seems like you would need to lengthen the X lead-screw to make use of the new end. Just curious.

Ed

[RobWilson]

Hi Ed

They were a fab job , welded up ,i am converting my 626 mill to CNC , in doing so i had to make new ends ,to fit ballscrews and motors





Ongoing project

Sorry for going off topic Wong


Rob