Carbide turning and expanding mandrels

[230grRN]

Just curious to know if anyone is interested and some. I'm having a couple sets ground up for me and could have more ground if there is any interest in them.

They will fit the Sinclair expander and neck turn tools. I'm having my sets ground up in .0005" increments for the calibers I use most.

 

[dmboat]

Just curious to know if anyone is interested and some. I'm having a couple sets ground up for me and could have more ground if there is any interest in them.

They will fit the Sinclair expander and neck turn tools. I'm having my sets ground up in .0005" increments for the calibers I use most.

Who is doing this for you?

 

[230grRN]

A local grind shop is doing them for me.

 

[Lapua40X]

You need to fix the facebook link in our signature line. Looks like you forgot to put a space where it's needed.

 

[spclark]

Any idea yet as to what a set (how many to a set?) will cost?

These basically straight expanders or can they accommodate longer tapers for working necks up from a smaller diameter?

 

[ireload2]

Carbide is great if the finish is about a 4 Ra and they are affordable. I am not sure an expanding mandrel needs to be carbide.

 

[230grRN]

They will be sets of 5 in .0005" increments CNC ground, just let me know the size range you want and they will grind it. They will not be taper ground, but will have a radius on the end, just like the sinclair mandrels. I'm still waiting on my set, but cost will be around $140 a set shipped.

Once I have my set I'll run them through there paces and make sure they are GTG before ordering any for others, cause if they are junk, I'm the only one out time and money.

To answer Mr. Ireload2's question, No carbide is not nesecessary for expanding mandrels and steel gets the job done, however I want properties steel can't offer, hardness, wear resistance, and lower coefficient for friction.

 

[spclark]

Carbide is great if the finish is about a 4 Ra and they are affordable. I am not sure an expanding mandrel needs to be carbide.

I'm not either but if I'm buying into a custom set of mandrels that potentially can include both turning style as well as a single expander for a given cartridge design, I'd like to have everything the same material. Just curious, that's all

 

[ireload2]

The lower coefficient of friction matters not at all to the press with an expanding mandrel.
I would also contend that a RC 64 tool steel expanding mandrel is far away hard enough to last forever. This is based on about 10,000 hours making parts of aluminum and steel using Rex 95 and MoMax tool bits. Expanding a .010 to .012 thick case neck is nothing.
The advantage of steel is that it is much cheaper and you can polish them to customize the size where as carbide is difficult to polish. You can own 4 steel expanders for the cost of one made of carbide. I like carbide tooling more than most but very few of us will ever use a carbide tool enough to make much difference.

They will be sets of 5 in .0005" increments CNC ground, just let me know the size range you want and they will grind it. They will not be taper ground, but will have a radius on the end, just like the sinclair mandrels. I'm still waiting on my set, but cost will be around $140 a set shipped.

Once I have my set I'll run them through there paces and make sure they are GTG before ordering any for others, cause if they are junk, I'm the only one out time and money.

To answer Mr. Ireload2's question, No carbide is not nesecessary for expanding mandrels and steel gets the job done, however I want properties steel can't offer, hardness, wear resistance, and lower coefficient for friction.

 

[timeout]

I don't do much neck turning anymore. If I did, I would love carbide for my 21st Century lathe.

 

[230grRN]

The lower coefficient of friction matters not at all to the press with an expanding mandrel.
I would also contend that a RC 64 tool steel expanding mandrel is far away hard enough to last forever. This is based on about 10,000 hours making parts of aluminum and steel using Rex 95 and MoMax tool bits. Expanding a .010 to .012 thick case neck is nothing.
The advantage of steel is that it is much cheaper and you can polish them to customize the size where as carbide is difficult to polish. You can own 4 steel expanders for the cost of one made of carbide. I like carbide tooling more than most but very few of us will ever use a carbide tool enough to make much difference.

I don't disagree at all, and have made many tool steel mandrels for myself. In this case my want out weights my needs, and carbide is what I want.

 

[BoydAllen]

If you play around with a concentricity gauge while expanding, measuring before and after, you may notice that cases become significantly more crooked from being expanded. Taking this a little farther, and doing some experimenting, you may be able to see that when the force required on the press handle exceeds some amount, that case shoulder brass is stressed to the point that it deforms slightly, asymmetrically, which is why the necks become less aligned with the case body. From all of this, you may conclude that mandrel friction, the effectiveness of the lube, and press manipulation technique all have roles to play in the final outcome. All of this assumes that you care about how straight your expanded cases are. I have steel expanding mandrels in several styles, and a carbide expander mandrel. The carbide mandrel requires less force than the steel mandrels. I imagine that all of this is much less important when your are expanding a neck that is already at the size that you will be turning at (making a slight adjustment for turning mandrel fit), but my experience has mostly been that of starting with .220 Russian cases, and finishing with loads that have turned necks and 6mm bullets, that will upon firing produce 6PPC cases.