Slipping MT2 tailstock

[Parlo]

I would venture to say the reamer is harder than the hardness of the quill by a slight if not large margin.

There’s really no need for the quill to be harder than it would need to prevent undue wear.

The reamer absolutely needs to be as hard as can be without being brittle.

The quill can sacrifice some structural strength for high surface hardness as it has a relatively large mass & needs to last a long time. It is a prime part for case hardening allowing a very high surface hardness for wear resistance and a durable core for strength.

A reamer also needs to resist wear without being too brittle so it can withstand cutting forces on the small sections of the flutes. I suggest that the hardness of a reamer is less than the surface hardness of the quill.

If we consider the taper on a reamer or drill, they are soft and welded to the hardened cutting portion.

Hardness is relative. Hmm, you might be on to something, it's hard to tell if the reamers were cutting or putting new metal in. the finish could have ended up looking good either way.

Yes, my post said that the hardness of the quill was relatively greater than the soft tapers on drills and reamers.

I doub't if your reamers were putting new metal in, perhaps someone can enlighten me how this happens.

The quill sockets generally don't wear, more often they pick up galling from soft spinning tool tapers. Morse taper reamers remove this soft galling and should not cut the original taper, preserving the original alignment and geometry. Another reason why morse taper reamers aren't as hard as the quill surface.

 

[pontiac428]

I doub't if your reamers were putting new metal in, perhaps someone can enlighten me how this happens.

I figured you already knew from the way you accused my reamers of not cutting.
pontiac428: Done it, bought reamers, performed the job got results
Parlo: Still talking about reamers not cutting

 

[Parlo]

It seems most tailstock quills are hardened & would be difficult to ream with HSS, although they will remove galling. A morse taper reamer has a huge amount of engagement ( it's a locking taper ) & therefore needs a lot of force to cut, especially to get it started. I guess your tailstock quill was one of the soft ones.

p.s. No need to be rude. It's a forum where we can all post our experiences, even reaming. This thread does not entirely relate to your posts.

 

[Makintrax73]

It seems most tailstock quills are hardened & would be difficult to ream with HSS, although they will remove galling. A morse taper reamer has a huge amount of engagement ( it's a locking taper ) & therefore needs a lot of force to cut, especially to get it started. I guess your tailstock quill was one of the soft ones.

p.s. No need to be rude. It's a forum where we can all post our experiences, even reaming. This thread does not entirely relate to your posts.

It did certainly seem tough to cut, but I wasn't pushing it hard because I was worried about digging in.

Based on the chip pattern I'd say it only removed the ridges caused by galling. Since it improved it I stopped.

I bored a 5/8" mt2 bit though 1" 1018 today. It was certainly better, but I had to put a hardwood block on the tip of the bit and whack it good to seat well.

 

[RaisedByWolves]

It seems most tailstock quills are hardened & would be difficult to ream with HSS, although they will remove galling. A morse taper reamer has a huge amount of engagement ( it's a locking taper ) & therefore needs a lot of force to cut, especially to get it started. I guess your tailstock quill was one of the soft ones.

p.s. No need to be rude. It's a forum where we can all post our experiences, even reaming. This thread does not entirely relate to your posts.

So you have tried reaming a tailstock taper?

 

[Parlo]

Yes, but only to remove galling, I've never tried to remove metal from the quill.

 

[RaisedByWolves]

I took a file to the tailstock quills of two lathes here, a Harding ands our morisiki.

Both were soft enough to mark with a file.

 

[Parlo]

I took a file to the tailstock quills of two lathes here, a Harding ands our morisiki.

Both were soft enough to mark with a file.

I just tried to scratch my Colchester tailstock quill with a hss centre drill and it just skidded over the surface. The same on my Proturn cnc quill. I always thought files were harder than HSS as they are so brittle.

 

[homebrewed]

An alternative thought on the quill vs. reamer hardness issue. If the problem is due to a hunk of swarf embedded in the quill it probably isn't hardened, so a reamer could remove it.

This begs the question, how could it become embedded? Perhaps friction welding?

 

[benmychree]

I think that when reaming a taper, the use of the center and crescent wrench is the better approach than the collet, but care must be taken th be assured that the center is aligned in a true manner to the other taper.