Threading tool holder

[ksouers]

I’ve preferred grinding my own HSS lathe tools but lately I’ve been trying out carbide and HSS inserts. One of the tools I’ve always had trouble grinding accurately was a threading tool. It seems I can never get the angle exactly right, always just a tiny bit narrow or too wide.

In my last tool order with LMS I picked up some HSS threading inserts. Now I needed to make a holder for them. I cut a piece of 1/2 inch square 1018 steel about 3 inches long. Since the inserts are triangular all the corners are 30 degrees. Getting out my trusty 30 degree angle plate I set up the square bar vertically and faced off the front horizontally.

The bar was then flipped 180 degrees and also angled 30 degrees so the face I just finished is now vertical. A pocket for the insert was side milled .125 deep, the thickness of the insert.

One of the inserts was glued to the pocket with Locktite, then a transfer punch was used to mark the center of the screw hole. The bar was heated slightly to release the Locktite and back to the mill for drilling and tapping for a 6-32 screw.

An insert was mounted and a 35 degree angle was used to mark out the relief on the right side.

And done.

A couple test cuts done in 1/2 inch 4130 steel.
16 TPI on the left, 32 TPI on the right. Yeah, it was worth it!

 

[Deanofid]

Thanks for this, Kevin. Very good write up!

Dean

 

[tel]

Yep, nice post which will be useful to me in the (very) near future. A karma point is called for I think

 

[Maryak]

THANKS Kevin. :bow: :bow:

Best Regards
Bob

 

[wm460]

Very interesting Kevin, thanks for sharing.

 

[ksouers]

Thanks guys. The threads came out noticeably better than with my hand ground tools.

This isn't a difficult tool to make, an easy Saturday morning job. Hopefully some of the noobs will realize that making tools is fun and they don't have to spend megabucks to have them.

Tel, thanks for the karma. Post up your tool when you make it.

 

[gbritnell]

Nice job on the toolholder Kevin. I normally grind mine from a high speed blank like most people but that would sure make life easier. Drats, now I have to make something else!!
gbritnell

 

[CrewCab]

Nice one Kevin :bow: Cheers

CC

 

[ksouers]

Drats, now I have to make something else!!

Thanks George. Just returning the favor ;D
I could tell right off the bat that their grind was much better than my hacking. A double bonus, the insert is HSS and it's made in USA. It cut really nice, too. The chips coming off that 4130 looked just like a lead alloy, nice bright and shiny.


Thanks CC.

 

[JimM]

Useful looking tool - what size insert did you use ?

Cheers

 

[kendo]

Hi Kevin
Really nice piece of work, may have ago myself.Thank for the info
Cheers
Ken

 

[ksouers]

Useful looking tool - what size insert did you use ?

Cheers

Jim,
It's a 3/8 IC.
Here's the link to LMS http://www.littlemachineshop.com/products/product_view.php?ProductID=3468&category=-1550042347


Thanks Ken.

 

[Paulsv]

I just found this thread, and I have a question. LMS lists two different HSS threading inserts. They appear to be the same except that one (the one that kevin provided a link to) has a 0 degree relief angle, and the other has an 11 degree relief angle. When would you use the different relief angles? Is one for small pitch threads and one for larger pitch threads? Or for cutting different materials?

 

[Lew Hartswick]

Wow! $13. for one of those in HSS. I'll keep grinding ours on the surface grinder
with the holding fixture that makes the + and - angles 30 deg. Set up time is a
bit but I can do 3 or 4 in a few minutes then.
...lew...

 

[Blogwitch]

I'm a bit like you Lew.

I can buy pre brazed tungsten tipped threading tools for about 4 squid (6 bucks), then, when needed, a quick swipe on the surface grinder I can resharpen them with no problems. I made myself a couple of plate angle gauges, one at 30 degs and one 27.5 degs (for Imperial UK). Set up time is seconds using my normal grinding vice.

Blogs

 

[kvom]

I recently purchased this tool:

http://www.mesatool.com/index.php?main_page=product_info&cPath=4&products_id=14

The same insert goes on each end. One end for external threads and the other, insert set crosswise, for internal threads.

 

[Paulsv]

That Mesa tool holder looks nice. Good price, too. I'm tempted. Checking out the inserts, it seems to me like they have substituted their own parts-numbering system for the inserts. At least, I can't find any insertw with similar number designations anywhere else. Have you figured out the ANSI number for the insert that the tool is made to accommodate? (so you can find it elsewhere, or get other inserts that will work in the tool?)

 

[gunboatbay]

I queried Jim Wilson at Mesa tool a year or so ago about his inserts and he told me they're not available anyplace but from him as he designed them and has them made elsewhere (I presume offshore, but don't know). His early inserts chipped too easily, but he's since improved them (either the design or the material) and they do a great job in most metals.

 

[Paulsv]

I checked them out a little more closely, and noticed that the Mesa tool can only make threads down to 11 tpi. The insert is too narrow to cut the larger threads. I emailed them about it, and he said he was working on one with a 1/4" insert, which would be large enough for 8 tpi threads, which is what I need to cut threads to match my spindle, for an ER-32 collet chuck. He didn't give a timeline. In the meantime, I think I'll have a shot at making a toolholder for the HSS inserts. I'd like to try one that will do both external and internal threading, like this one:

http://www.arwarnerco.com/warner_products_kits_threading_k18.html

If the Warner tool ($85) was priced closer to the Mesa tool ($30), I'd probably buy it, but it should be fun to make it.

I'm still confused about the difference between the two HSS stand-up threading inserts: one with a 0 degree "relief angle," and one with an 11 degree "relief angle." By relief angle, do they mean back-rake on the cutting tip, or side clearance angles? Why would I want one or the other? Smaller versus larger threads? Different materials? I guess I could just buy one of each and compare them when I get them.