Screaming deal. Solid carbide, insert type boring bars

[Buckshot]

On E-Bay

1/4" bar:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=280186989840&ssPageName=WATCHM_BC_T_2

Check the sellers store as they also had 5/16" and 1/2" solid carbide bars.

................Buckshot

[James Wisner]

Who buys carbide tipped boring bars.

I recycle my carbide endmills into solid boring bars and also I have 2 1/2 pounds of certanium 70F silver solder to attach the carbide inserts to any steel bar I want.

At any given time I have about 15 pounds of old carbide inserts and endmills that are past their prime.

Jim Wisner
Custom Metalmsith

[Buckshot]

Who buys carbide tipped boring bars.

I recycle my carbide endmills into solid boring bars and also I have 2 1/2 pounds of certanium 70F silver solder to attach the carbide inserts to any steel bar I want.

At any given time I have about 15 pounds of old carbide inserts and endmills that are past their prime.

Jim Wisner
Custom Metalmsith

..............Jim, the deal here is that the bars themselves are solid carbide and they take carbide inserts. These aren't steel bars taking inserts or soldered chips on steel bars. I figure I got a screaming deal on carbide bars from MSC when they had a promotional deal on them from Circle C for like $107 plus 10 inserts.

These bars from this seller are half that, but don't come with the inserts. I don't know who the maker is on these but for the price I'd gamble.

I've re-used worn endmills reground into certain form tools, as boring bars and such (not any carbide ones though). As a rule they're not 4" and 6" long like these are.

...............Buckshot

[Woodtroll]

Are the inserts for these universal, or are they proprietary? If I buy the bar, will I likely end up being "stuck" buying expensive inserts from only one supplier? I'm looking at the 5/16" bar, which calls for CCMT21.5 inserts. I'm pretty green at machine work, so I don't know what to make of this.

I have one of the small Cummins lathes (7x12), and have a split sleeve that goes into the tool holder that clamps down onto the boring bars I have (1/2" round shank). Can I make a 1/2" OD x 5/16" ID split sleeve to hold this bar inside the 1/2" sleeve, or do I need some other way to attach it to the toolpost?

As an aside, would this bar/ insert work to take about a 0.005" cut (0.010" total) out of a Lee sizing die? I know that these dies are hardened to some degree, but not sure if the carbide would make a mess of the cut or not? Of course, I would finish-hone it after boring.

Thanks, Regan

[Buckshot]

Are the inserts for these universal, or are they proprietary? If I buy the bar, will I likely end up being "stuck" buying expensive inserts from only one supplier? I'm looking at the 5/16" bar, which calls for CCMT21.5 inserts. I'm pretty green at machine work, so I don't know what to make of this.

It's an industry standard insert.

I have one of the small Cummins lathes (7x12), and have a split sleeve that goes into the tool holder that clamps down onto the boring bars I have (1/2" round shank). Can I make a 1/2" OD x 5/16" ID split sleeve to hold this bar inside the 1/2" sleeve, or do I need some other way to attach it to the toolpost?

Is it the 4 position toolpost that came with the machine or is it the Aloris type, like this? (below)

http://www.fototime.com/07A1C1C51FF349D/standard.jpg

I don't know if I'd put a split sleeve inside a split sleeve. It would work but I'd personally want assurance of a bit more positive hold then that might offer. Just make one for whatever size the current one is.

As an aside, would this bar/ insert work to take about a 0.005" cut (0.010" total) out of a Lee sizing die? I know that these dies are hardened to some degree, but not sure if the carbide would make a mess of the cut or not? Of course, I would finish-hone it after boring.

The insert will do that easily. Your best finish will come via power feeding so I hope that's what your plans include. To finish, take a light cut and a slow feed. As you approach the last thousandth, after the bar has fed the length of the die body, stop the lathe and back the carriage and tool out. Measure the bore and if still about a thou off, re-start the lathe and feed the tool again without changing your DOC.

You want to leave yourself the better part of a thousandth remaining to polish. Regardless how nice the finish looks to your eye, the first part of your honing/polishing is going to be simply knocking off the tops of the ridges, so will go fast at first.

Thanks, Regan

.......................Buckshot

[Woodtroll]

Thanks, Buckshot, I appreciate the reply.

I have only the 4-position toolpost that came with the machine (at least for now). My boring bar holder is a piece of square key stock (5/8" maybe?), with a half-inch hole bored through it, and slit lengthways. I would make a similar one to hold the 5/16" bar, but have no 4-jaw chuck to center the square stock.

Also, regarding that die project that we discussed a few weeks ago- I'll be sending it your way within the next week or so.

Thanks again for your help (and patience!). Take care, Regan

[Buckshot]

Thanks, Buckshot, I appreciate the reply.

I have only the 4-position toolpost that came with the machine (at least for now). My boring bar holder is a piece of square key stock (5/8" maybe?), with a half-inch hole bored through it, and slit lengthways. I would make a similar one to hold the 5/16" bar, but have no 4-jaw chuck to center the square stock.

Also, regarding that die project that we discussed a few weeks ago- I'll be sending it your way within the next week or so.

Thanks again for your help (and patience!). Take care, Regan

...............Regan, just take a 5/8" bolt and bore a 5/16" hole through it, and then slit it with a hacksaw unless you have a better means. Use that for the holder.

I don't remember the die deal :-). It was a couple weeks ago!

................Buckshot

[Woodtroll]

Buckshot-

I'll send you a PM.

Thanks, Regan

[Buckshot]

..............I haven't gotten the carbide bars from the E-Bay vender yet, but these are the ones that MSC was offering:

http://www.fototime.com/76745E9F64C31AA/standard.jpg

Clockwise from the left is 1/2" x 6", 3/8"x6", 1/4"x4", and 3/16"x4".

http://www.fototime.com/F927426EF9100A0/standard.jpg

Closeup of the insert on the 3/8" bar.

...................Buckshot

[georgeld]

That's pretty small Buck.

Those solid carbide bars are made to grind the cutter on the end, rather than
attach a bit. We used them in the shop many yrs ago that way. Brittle as hell, so
DO NOT touch any part with the part stopped!! Just a touch and they're chipped.
This is for anyone that don't know already. Most of us that have used it before have
learned that lesson repeatedly the hard way. Right?

Also, for you newbies to machining. Carbide tools take a special grinding wheel.
They'll just eat a standard wheel right up. So save your money up and buy the
correct wheels and use them solely for carbide and don't ruin them by grinding
HSS, or softer steels.

[Buckshot]

[QUOTE=georgeld;285714]That's pretty small Buck.

Those solid carbide bars are made to grind the cutter on the end, rather than
attach a bit. We used them in the shop many yrs ago that way. QUOTE]

.............George, I'm not following you here. The ones I'm talking about are solid carbide bars that accept replaceable carbide inserts. Are we talking about 2 different things?

.................Buckshot