Thread: Changing the top quill bearing to a taper one on a HM52

Originally Posted by Stustoys

Hi Simon,
Not sure where in Melbourne you are.
Anywhere near Clayton?
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Stuart

Thanks Stuart. It's about 30Km away but I do visit around that area from time to time. Wife works in Dandenong which is near there.

Thanks for the info!

Simon

Hey Dave,
So it's been a while since I posted but I wanted to say I have not gone away I have just been to busy to hunker down and get anything done. In between between housing projects I have been slowly sneaking in some time to work with my lathe in preparation for making this quill nut. I actually had the cross slide nut hang up on me and ended up breaking everything down and cleaning it, of course I gave the compound equal treatment. I have the cross slide traveling smoothly again and so I decided it was time to gear up for some metric threading. I changed the open gears in the back of my lathe to accommodate for the M40x1.5 pitch metric threads that the nut needs to have. I just did a test run on a piece of aluminum roundstock and I guess for a newby first timer it came out pretty good. I have included a picture as well as the steel dial indicator holder I milled for my aloris clone quick changer (I said I would post the indicator holder a while ago). Anyways I'm also using a 4 jaw chuck and I rather enjoy indicating the parts in. I did have a question though. To what depth did you cut your internal threads and did you purposely make it a little loose in order to help accurately set the pre-load on the top tapered bearings for quill? As always, thanks Dave.
-CJ

Don't worry, we all get buried in the shed away from the forum. Good to hear your progressing with your lathe and mill.
The original nut was a bit sloppy, so I made mine a bit tighter. It can be done up easy with my fingers but has not got much slop in it. The best way is to have the spindle out and check it when your getting close, it should be around 0.81mm deep.

For metric screw threads the thread depth is found by multiplying the pitch (which in this case is 1.5mm) by 0.61, and the nut by multiplying the pitch by 0.54.

Dave

Awesome, thanks Dave.

Hi Dave,

I have one more question about the takedown of the mill. I have been having a heck-of-a time removing the top collar which sits underneath the top pulley. Might I ask how you removed yours? That collar seems to be bonded to the mating piece and I don't want to bang on it to much more than I already have . Thanks Dave. Here is a pic of the assembly I'm taking about.

Thanks!
-cj

pic didn't show up on the last reply. here it is.

I went looking through my pictures but it seems I don't have any more of this part.

Undo the 4 Allen head bolts around it seen in the picture, then from memory I used a piece of wood from up inside the quill to knock the whole lot out, it will bi tight. You will have to take the quill out but it looks like you already have.

Because it was such a tight fit on mine I put it in the lathe and used a bit of emery to bring it down a little.

Once you have it out you then press it apart after taking the circlips out (from memory again) I just used my bench vice.
You will find a spacer between the 2 bearings, so make sure it goes back in. Some are just plastic so you might want to make a new steel one up.

Dave

Ok cool thanks Dave. I had removed the bolts but it was still stuck tight (the picture was taken pre bolt removal). I used a steel rod and brought it up through the head casting (where the spindle used to be) via some wood blocks on the knee. I then made contact with the top bearing assembly and thought, hmmm maybe I should ask someone about this before I go and potentially bust something. I had looked at the assembly provided by Grizzly but it has to be among the worst drawings I have ever seen. A caveman with a piece of charcoal might be able to compete with what Grizzly provides. Anyways thanks again and I hope to have everything up and running again soon. Of course I will get everything together and post pics when the time comes.
-cj