The clearance holes for M6 cap screws were finally done. I've conquered the fear of having misaligned holes with the help and encouragement from various people. This operation may be easy for many readers out there, but I always have problem of getting the clearance hole matching up with the screw holes. Enough "talking", here are the pics:
Below is a short vid showing that the job spinning. Not too bad, I suppose.
I'm rather happy with the result of today's session. In my next session, after my Bangkok trip, I'll be shortening the cap screws to the required size and trim off the excess on the nose to get ready for threading. The taper bore will be done last.
I was up as early as 7am this morning. Wanted to sleep in on this Sunday morning but just could not. After washing up and 2 cups of coffee, I started working in the shop.
The job of the day is the recess at the back of the chuck which needs to be precisely done so that it fit the registration boss on the spindle flange without any wobble. I asked Dave my last couple of questions on the forum so that I've clear images in my mind of how I should carry out this operation.
Not much pics taken as the session was rather short. I was concentrating intensely when bring the recess to its final size.
The "floor" of the recess was finished off as best as I can. It feels smooth now but doesn't have the bling shown in Rob's and Dave's pics in the forum. It makes me wonder if its the camera as mentioned by some other members of the forum. Mmmm...
Next up, the mounting holes. The 3 holes are clearance holes for M6 cap screws. After completing the recess, I suddenly realized that I have forgotten to scribe the PCD for the mounting 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.
This is how the set of Transfer Screws looks like, for those whom I tried asking if they're available in SG.
The threaded portion is to be screwed onto the mounting hole on the spindle flange, leaving the little pointy portion sticking out. The collet chuck will then be placed onto the flange using the recess as a guide. It will then be tapped with a mallet to have the hole positions transferred to its back.
But I'm still concern about one thing; will the trapped air causes the collet chuck not seating properly affecting the transferring of hole locations to be off?
I'll know when I received the item, together with a 3" angle plate.
That is all for today. Have a blessed week ahead with unceasing fruitfulness! Shalom.
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...
Pushing the flange of the chuck to be against the flange with one hand, I tried moving the chuck against the registration boss on the flange. 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 was also there.
I measured the gauge with the caliper - 70.01mm. The registration boss on the spindle flange measures 69.99mm. That means that the recess is 0.02mm over sized... No wonder the gauge fits so tightly into the recess of the 4 jaw chuck. I've to press it in with my hands.
The work will still be completed. I'll decide if I need to redo the project after I test the completed chuck.
I finally found a suitable piece of aluminium to make the gauge for the recess. It was cut off from a long piece of 81mm diameter rod. No much of convincing required this round to get the piece I want. I've also collected the 80 degree insert tools from Mike. From my reading online, it is good for roughing due to its shape. The pair of left and right tool cost me SGD124 if I remember correctly.
With the right stock on hand, I happily turned down the aluminium block to close to the required dimension and slowing turning bit by bit till it fits the recess at the back of the 4 jaw chuck. After playing with steel for a while, I find cutting aluminium fast and easy. The job was quickly completed.
The half done ER32 collet chuck was remounted on the 3 jaw chuck to clean off the remaining skin and the back faced. I'm now ready to turn the recess.
The experience gained while turning the nose helps. I'm starting to get some feel of spindle speed, depth of cut, and rate of feeding. Good that I'm feeling more confident in use the lathe.
The next challenge would be the recess, cutting the threads, and boring the taper. I'll be taking it slowing to gain more understanding of the process.
The session was a short one which saw the completion of turning down the nose to the size which allows the stock to be flipped over and fasten in the jaws of the 3 jaw chuck. I wanted to turn this section down to 45mm, leaving 5mm for truing up later - after the recess and mounting holes are done, but changed my mind after GeneK suggested that he would prefer to have the recess and mounting holes done first to ensure concentricity. The main objective of this session was then to clean up the flange and to achieve a smoother surface.
The spindle was bumped up to 660 rpm and the Sherline's carbide insert tool with tip of 0.4mm radius was used. The cut was especially light with very slow feed. I was quite please with the result though it may not seem to be as nice looking as what DaveH showed on his ER25 Collet Chuck.
I made a trip down to Kelantan Lane the next day after finishing my appointment at the lawyer's office. As I was in a bit of a rush, I didn't check the item picked by the metal shop assistant. Realized that the aluminium round stock I bought is 120mm in diameter only when I got home. Looks like another trip is needed...
From this exercise, I discovered that to improve the surface finish, the tip of the insert tool needs to be angled against the stock such that the side is very close to the surface of the stock to be turned.
Once the gauge for the recess is done, I'll be able to carry on with my work to bore out the recess and drill the mounting holes.
That's all for now. Like always, be blessed.
The ER32 collet chuck has always been on my want list for a long time. My search online came to a nought as none of those I found matches the Proxxon spindle flange. The spindle flange on the Proxxon has PCD of 83mm for the M6 mounting cap screws and requires recess of 70mm in diameter to mount accurately on its boss. I've 2 options available to me:
After reading several build logs and gotten lots of encouragement from the good folks of Metalworking Fun & Madmodder, I decided on option 2 - to make a Wongster's Production ER32 Collet Chuck.
I took a short video showing how "well" I centred the stock. The wobble was pretty obvious.
That's all I have for now. hope to get more done in my next session.