MT 6 1/2 One Piece Dead Center

[erikmannie]

So here is what I have so far. From left, stock PM adapter sleeve with MT4 dead center, 1018 steel first try, 1045 steel from today, another 1045 from last week (I still need to cut the 60° tip), and 4” 4140 prehard round stock for the last one.

I’m going to force myself to try my taper attachment for the chromoly one. I have been afraid to use the taper attachment; I was afraid that I won’t be able to re-engage the cross slide after disengaging it to use the taper attachment.

 

[erikmannie]

Too bad your chuck doesn't have 2-piece jaws - you could have made soft jaws to hold the tapered part when you turned it around. Looks like you got what you need out of it though. Nice job.

I couldn’t figure how one would mount a taper in a two jaw.

Why do people buy 2J chucks? Why not just take two jaws out of a 4J?

 

[davidpbest]

2 piece jaw - not 2 jaw. Here is a lathe chuck with 2-piece jaws:

And here is an example where the top part of the jaw has been replaced with an aluminum substitute that can be machined to any configuration necessary to securely hold the part:

Here's another example of a soft jaw machined to precisely fit the OD of a shallow part that would be impossible to grip without profiled soft jaws:

 

[erikmannie]

2 piece jaw - not 2 jaw. Here is a lathe chuck with 2-piece jaws:

View attachment 352230

And here is an example where the top part of the jaw has been replaced with an aluminum substitute that can be machined to any configuration necessary to securely hold the part:

View attachment 352236

Here's another example of a soft jaw machined to precisely fit the OD of a shallow part that would be impossible to grip without profiled soft jaws:

View attachment 352238

Thank you for the comprehensive answer. Those pictures appear to be from a very clean, professional operation.

I happen to have a 12” TMX 2-piece jawed 4J independent chuck en route to me now. I hope to one day be able to afford the soft top jaws for it. $200 for a set of 4 soft top jaws:

TMX Soft Top Jaw for 12" Independent / Scroll Chucks, 1pc, 3-884-312P

TMX Soft Top Jaw for 12" Independent / Scroll Chucks, 1pc, 3-884-312P

www.smalltools.com

 

[davidpbest]

You will find much more affordable jaws (for your chuck and vises) at Monster Jaws.

 

[SLK001]

When you make these, make them in pairs. Hold the stock for the first taper in the 3-jaw and cut the taper to within 0.005" of the final size. Now, remove the chuck and insert the first taper into the spindle, then cut the second taper to within 0.005". Flip them around again, then cut to final size. Now part the piece and cut the points. Using the spindle keeps the runout very low (lower than the 3-jaw can). If you desire to use your welding tools, drill a center hole and make yourself a "negative center" so that you can mount your tapers between centers and finish off your tapers.

 

[erikmannie]

When you make these, make them in pairs. Hold the stock for the first taper in the 3-jaw and cut the taper to within 0.005" of the final size. Now, remove the chuck and insert the first taper into the spindle, then cut the second taper to within 0.005". Flip them around again, then cut to final size. Now part the piece and cut the points. Using the spindle keeps the runout very low (lower than the 3-jaw can). If you desire to use your welding tools, drill a center hole and make yourself a "negative center" so that you can mount your tapers between centers and finish off your tapers.

I like the first idea better, but I would like to make a 60° negative (i.e.”cup” rather than “cone”) center (two deep cup-types pictured below).

In fact, I think the dead center pictured above that I had planned to cut to a 60° tip will now be drilled or cut to a negative center. I could either use a large center drill or use the compound to cut a 60° internal taper.

I would be inclined to choose the center drill, like you said. I wonder what these “negative bull nose” types are used for.

 

[erikmannie]

Here is the last one. I decided against a negative center, and went for a classic 60° tip.

I had this in the tapered spindle nose when I cut the taper.

 

[erikmannie]

I took off my D1-6 4J chuck (for the first time, it needed some coaxing). I tested all of my 6 1/2 MT stubby dead centers & they all fit perfectly.

In order to test the fitment, I recut the 60° angle on all of them while they were in the spindle nose. Here are some pictures of that.

 

[erikmannie]

I put on a 14” face plate. I’m gonna face it.