Slipping MT2 tailstock

[tq60]

Mt2 is fairly small, not sure of how large of drill bit when good.

There are ways to brace the bit so it does not rotate.

Below is 3.5 inch hole saw in 1.25 thick steel at maybe 45 rpm.

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[pontiac428]

There are ways to brace the bit so it does not rotate.

For a hole saw as shown, that's probably okay. For any type of drill, though, the deflection caused by the lever at the chuck will cause the center of the cutting tool to climb up and to the rear, away from the work's center. I would allow axial twist in the tool and tailstock before trying to support the work as such.

Somebody is going to scream bloody sacrilege, but here's a trick. Go over to your carbide grinder and find some tungsten carbide grinding dust. Mix the dust with a few drops of oil or grease to make a paste of a similar consistency as anti-seize. Rub a *little* dab of that into your taper and install it- it will hold tight. Some of the tiny carbide dust will embed into the spindle/tailstock/tool shank without causing any type of runout, making a lasting hold long after the paste is wiped off. Some of you may be familiar with carbon fiber paste, this is the same concept except with hard steel. I am comfortable doing this with my own machines. The carbide paste is useful in so many applications, including gripping Philips head screws against a cross tip bit, even when the slots are stripped beyond recognition.

 

[RaisedByWolves]

For a hole saw as shown, that's probably okay. For any type of drill, though, the deflection caused by the lever at the chuck will cause the center of the cutting tool to climb up and to the rear, away from the work's center. I would allow axial twist in the tool and tailstock before trying to support the work as such.

Somebody is going to scream bloody sacrilege, but here's a trick. Go over to your carbide grinder and find some tungsten carbide grinding dust. Mix the dust with a few drops of oil or grease to make a paste of a similar consistency as anti-seize. Rub a *little* dab of that into your taper and install it- it will hold tight. Some of the tiny carbide dust will embed into the spindle/tailstock/tool shank without causing any type of runout, making a lasting hold long after the paste is wiped off. Some of you may be familiar with carbon fiber paste, this is the same concept except with hard steel. I am comfortable doing this with my own machines. The carbide paste is useful in so many applications, including gripping Philips head screws against a cross tip bit, even when the slots are stripped beyond recognition.

I just did this with clover compound on a brand new tool post and plinth as the mating surfaces were both so slick that the tool post would rotate when loosening the nut.

Let them scream BM, not hurting something that is already hurt, LOL.

As to that hole saw on the MT2 taper, your getting outside the intended working envelope there IMO.

 

[Makintrax73]

Received my MT2 finish reamer.

Rigged a test set up like this:



It's a 15/16 head bolt turn down to 1/2 round body with a beam torque wrench.

I was getting 5-7 ft lbs in the before test. I rigged the reamer in a 4 jaw, zeroed it, and gave it a few turns (by hand) with light pressure. It was clearly shaving off a couple high spots based on the chips stuck to the reamer being congregated in a few areas.

After test with it cleaned thoroughly was about 15 ft lb.

We'll see how it goes. Certainly it will be better, and based on the tiny amount of chips overall I certainly don't see that I did any damage at least.

 

[Parlo]

Aside from what has been mentioned earlier & assuming both tapers are clean. You must seat the taper, the books say that working pressure seats the taper, it does, but nowhere tight enough. Be sure to give the tool a good sharp tap into the tailstock.

 

[pontiac428]

With MT2, you have every right to seat it with a whack. But in general, the more expensive the mating parts and the larger the tapers, the more you can rely on seating with hand pressure. In other words, it's a symptom of wear and other problems. When I reamed the tapers on my Atlas, I let them work under power until I had fully restored bores. Just a thou or two, enough to see fresh steel throughout. From that point on, they were plenty sticky and worked under hand pressure consistently.

 

[Parlo]

With MT2, you have every right to seat it with a whack. But in general, the more expensive the mating parts and the larger the tapers, the more you can rely on seating with hand pressure. In other words, it's a symptom of wear and other problems. When I reamed the tapers on my Atlas, I let them work under power until I had fully restored bores. Just a thou or two, enough to see fresh steel throughout. From that point on, they were plenty sticky and worked under hand pressure consistently.

The larger the tapers = the larger the tool = the larger the torque. So I would always give them a sharp tap whatever the size, it's just not worth the gamble not to.
Did the reamers actually remove metal from the tailstock bore? Female sockets are generally hardened & tool shanks left soft. I guess it is cheaper to replace a tool than the tailstock quill.

 

[pontiac428]

The larger the tapers = the larger the tool = the larger the torque. So I would always give them a sharp tap whatever the size, it's just not worth the gamble not to.
Did the reamers actually remove metal from the tailstock bore? Female sockets are generally hardened & tool shanks left soft. I guess it is cheaper to replace a tool than the tailstock quill.

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.

 

[RaisedByWolves]

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.

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.

 

[pontiac428]

4130 HT is about 30 on the Rockwell C scale, HSS is about 62. I don't know what the problem is. I did the job, the job is done, it worked for a few years, I sold the lathe.