HF mini lathe gear faces are not aligned?

[gnsmith]

I've searched around and haven't found a post about this...

The gear faces on my mini lathe are not lined up. Only about 2/3 mesh between the middle gear and the gear on the end of the lead screw. I don't know for sure if it came that way, I didn't pay that close attention before I took it apart to clean and re-grease it. I could fix most of the problem by spacing out the "support plate" but I don't want to do that if somehow I don't have the lead screw installed right. It is all the way in the right pillow block and there is no play I can detect back and forth. I posted a picture that will hopefully make the situation clearer.

Any suggestions would be greatly appreciated.

Greg

 

[astjp2]

Shim them up so you have equal contact. You may find washers underneath the gears so use thin and thick washers to get them aligned. Tim

 

[gnsmith]

Shim them up so you have equal contact. You may find washers underneath the gears so use thin and thick washers to get them aligned. Tim

Thanks for the reply. I just wanted to make sure that I didn't get it back together wrong. I would have thought that others would have also posted about this but maybe its just to basic and obvious.

 

[BRIAN]

I think all change gears for minilathes are from the same company. So if you look at the gears you will find that the centres are offset so simply turning the gear over moves it in or out.
In your photo it looks like if you turn the 3 gears over the top 2 will move in and the lower one will move out bringing all into alignment.
This feature also allows you to get clearance between the compound gears on Shaft NO 2.
I have never had to add washers to my 7x12.

I hope this helps. Brian.

 

[BRIAN]

I think all change gears for minilathes are from the same company. So if you look at the gears you will find that the centres are offset so simply turning the gear over moves it in or out.
In your photo it looks like if you turn the 3 gears over the top 2 will move in and the lower one will move out bringing all into alignment.
This feature also allows you to get clearance between the compound gears on Shaft NO 2.
I have never had to add washers to my 7x12.

I hope this helps. Brian.

Brain fart!!! just reverse the instructions. It pays to engage brain before alowing fingers near keyboard.

Brian

 

[Chucketn]

I discovered the same misalignment when building and installing a fine feed banjo for my 7x14. I had some 20T and 80T gears salvaged from a couple of laser printers that matched the change gears and made a banjo to fit them. I also redesigned the stub shaft for the B-C gears to make it easier to change them. The new stub shaft secures from the outside, eliminating the hassle of trying to loosen/tighten the nut behind the gears when setting up for thread cutting. I made some custom washers to adjust the position of the gears and to prevent binding.

Chuck

 

[David Kirtley]

Here is where you adjust it.

Adjust the height and then lock it in position. I don't remember if it had a jam nut or not. If not, just put a washer under it to shim it up to the alignment you want.

(not my pic. just snagged from images.google.com)

 

[Bill C.]

I've searched around and haven't found a post about this...

The gear faces on my mini lathe are not lined up. Only about 2/3 mesh between the middle gear and the gear on the end of the lead screw. I don't know for sure if it came that way, I didn't pay that close attention before I took it apart to clean and re-grease it. I could fix most of the problem by spacing out the "support plate" but I don't want to do that if somehow I don't have the lead screw installed right. It is all the way in the right pillow block and there is no play I can detect back and forth. I posted a picture that will hopefully make the situation clearer.

Any suggestions would be greatly appreciated.

Greg

View attachment 64863

The front to back alignment doesn't bother me as long as the gear teeth mash properly. In high school we had lathes that we had to change gears to change the feeds. As long as the idler gear was adjusted so that all the gears are interlocked with a little gap for lubrication all was well.

 

[Dunc1]

David Fenner wrote a series of articles for Model Engineers'Workshop (MEW) about the mini-lathe (started end 2007 thru Dec 2008). The first installment is available from
http://www.arceurotrade.co.uk/reviews/MEW133_p27-29.pdf (a two-part article, visit the arceurotrade website for part 1). Aligning the gears - using washers - is mentioned in the text that discusses photos 21a & 21b.

 

[gnsmith]

I think all change gears for minilathes are from the same company. So if you look at the gears you will find that the centres are offset so simply turning the gear over moves it in or out.
In your photo it looks like if you turn the 3 gears over the top 2 will move in and the lower one will move out bringing all into alignment.
This feature also allows you to get clearance between the compound gears on Shaft NO 2.
I have never had to add washers to my 7x12.

I hope this helps. Brian.

Brian, Thanks for pointing out that mini lathe gears are not symmetric. That makes a lot of sense and I did think of that but at least the 50 tooth gear (what I was using as gear D) is symmetric so I assumed they all were. You got my hopes up but for some reason all my gears are symmetric so flipping my gears doesn't make a difference. If they are supposed to be offset I suppose I could take a little off the hub on one side and add a washer to the other. The total hub with is correct as far as aligning to the end of the three shafts. Do you know how much offset there should be? The offset right now between the middle and bottom gear measures 0.114 so maybe 0.05 would work?

- - - Updated - - -

David Fenner wrote a series of articles for Model Engineers'Workshop (MEW) about the mini-lathe (started end 2007 thru Dec 2008). The first installment is available from
http://www.arceurotrade.co.uk/reviews/MEW133_p27-29.pdf (a two-part article, visit the arceurotrade website for part 1). Aligning the gears - using washers - is mentioned in the text that discusses photos 21a & 21b.

Thanks for the reference. Putting the washer behind the bracket as shown in 21b seems to be the best quick solution. I had done that too but wondered if the root cause was something I had done by mistake.