Clearance for plain bronze bearing for Hendey spindle

[RCPDesigns]

In an attempt to fix the spindle issue in my Hendey lathe I had the spindle ground including the MT5 taper. I'll need to make some new plain bronze bearings to fit the new dimensions of the spindle. What should gap should there be between the bearings and the spindle?

 

[johnoder]

I'll assume this is the conical bearing Hendey

Both front and rear are tapered

Front fitting is determined by relationship between front thrust face and taper. Rather that some magic "clearance" I like to get the least possible clearance that will allow the lathe to run a loaded speed without excessive heating.
MANY an old Hendey with these these bearings will lock right up ater the thrust case wears enough

Numerous threads on this forum about correcting this issue

 

[RCPDesigns]

Hey John, this lathe is a bit older, it has the straight bronze bearings. The bearings are split with flanges front and back.

 

[texasgeartrain]

Without seeing any parts in front of me, as a general number, in the vicinity of .001" on any kind of bushing or two halve type.

Being a spindle, and if your goal is as tight as possible, you might try like .0008", be sure to use a spindle oil, something thinner. Watch temps at high speed ranges. With end thrust of spindle in the area of .0008" to .0012" if thrust on a bronze washer or the like. Might go to .0005" if a ball or roller type thrust bearing.

If your goal is less worry, and reduced chance of lock up, then I'd do like .00125" on oil clearance. And do thrust as mentioned.

Again, thats without seeing the parts, knowing the speeds, etc

 

[johnoder]

Hey John, this lathe is a bit older, it has the straight bronze bearings. The bearings are split with flanges front and back.

Maybe 1 1/4 thou on dia - less is better (as far as precision) as long as they only get warm - not hot in working at speed.

My (used to be now) B&S #4 Universal grinder had 2" journals and would only warm to the touch at 1400 RPM - with essentially no measurable clearance (using Velocite 6) - lathes work harder and go slower

This puppy

 

[JST]

Spec for an SB that had about a 2" journal was max 0.0015, min 0.0007. Probably similar on yours.

Determined by an indicator, with a wood rod in the spindle pushing up, then down with about 50 lb force. Figure was for total movement.

 

[RCPDesigns]

Thanks for all the quick input!! To be sure I'm clear on this, 0.001 clearance would mean that ID of bearing is 0.002 bigger than OD of spindle? Or is it 1/2 thou around such that ID is 0.001 bigger than OD of spindle?

 

[texasgeartrain]

Thanks for all the quick input!! To be sure I'm clear on this, 0.001 clearance would mean that ID of bearing is 0.002 bigger than OD of spindle? Or is it 1/2 thou around such that ID is 0.001 bigger than OD of spindle?

Bearing ID .001" larger than shaft OD.

 

[dundeeshopnut]

Do you have any pics of this lathe or a thread started on it? Just for $#its and giggles, there is one listed on FB here in Quebec that I think is the same as yours with a single "stick" Norton quick change with plain bearings.

 

[99Panhard]

There was a thread on Jeff's lathe when he overhauled it...search on his screen name.
After the lathe was done and up and running he discovered that it must have had a serious crash at one point and the spindle was actually bent.

Found it!

1898 Hendey 14x6 restoration

1898 Hendey 14x6 restoration

 

[dundeeshopnut]

Thanks. I wasn't clued in that this was the same lathe as it seemed odd to do an over the top showroom resto on a machine with a bent spindle.

 

[RCPDesigns]

Thanks. I wasn't clued in that this was the same lathe as it seemed odd to do an over the top showroom resto on a machine with a bent spindle.

Yep, I had no idea that there was an issue with the spindle. I probably should've tried to make some test cuts before but it wasn't really in operable condition. Even if I had made some test cuts I probably wouldn't have noticed as I had never operated a lathe before.

 

[dundeeshopnut]

Yep, I had no idea that there was an issue with the spindle. I probably should've tried to make some test cuts before but it wasn't really in operable condition. Even if I had made some test cuts I probably wouldn't have noticed as I had never operated a lathe before.

Well no harm no foul. At least you are "makin' it right".[biga$$ thumbup here!] How much did it set you back to have the spindle trued?

 

[RCPDesigns]

Well no harm no foul. At least you are "makin' it right".[biga$$ thumbup here!] How much did it set you back to have the spindle trued?

$510 for grinding the spindle. I only received one quote for bearings and it was "at least $1000". The two shops I talked to did not have someone to solder the halves back together for final dimensioning so that add a bit of vagueness on the quotes. I offered to provide the rough machined and soldered halves for final machining and that brought the price down to "maybe $600" at which point I decided I should at least try it myself first. I'm not in the best part of town for machine shops.

 

[99Panhard]

Yep, I had no idea that there was an issue with the spindle. I probably should've tried to make some test cuts before but it wasn't really in operable condition. Even if I had made some test cuts I probably wouldn't have noticed as I had never operated a lathe before.

And...the chuck & backing plate on the lathe appear to have been fitted after the spindle was bent so they actually ran true. Jeff didn't discover the bent spindle until he tried to use collets...then it became clear that something was wrong. To be fair, this is such an odd problem that I'm sure I'd have missed it too.