DIY Tangential

[th62]

Finished off my tangential today. As I don't have a mill I had to cut the slots for the tool on the lathe. I welded the head to the body at 28 degrees and ground it all back on the belt sander. With back rake ground at 15 degrees it gives a side rake of around 7-8 degrees (depending on tool post angle) it cuts exceptionally smooth left or right leaving a nice spiral of swarf. Happy with that. This is the third I've made, trying different side and down angles for the head. All cut well but this one seems to be the best compromise for gaining access to the material being cut. I might start on a sharpening jig tomorrow.

[neksmerj]

You have done a terrific job on that tangential toolholder. A bit of blackening would enhance it even further.

Do you have any drawings you would care to share with us?

Ken

[Oldneweng]

I tried to get my head around how to make one then gave up and bought one. A big decision considering the cost for what is a pretty small tool for my lathe. This design looks so simple. What size HSS are you using. I would not mind making a bigger one. I have also thought of having one each set up for 55 and 60 deg thread cutting for when I finally get around to doing this. My Nuttall has too much wear to be any good for thread cutting although I have thought about aranging a lock for the cross slide to prevent the tool from digging in. 2mm is just too much slop. I am going to spend the time arranging for the installation of my new lathe tho. It is getting much closer. Main concern now is water. The back of the shed is reached by a track that is under up to 100mm water, the front by driving over back lawn which may be too soft for a 1.5 tonne lathe plus vehicle and trailer. All up about 4.5 tonne. Will have to see. If I stop playing around on the Forum I could get up and do some work on this. LOL

Dean

[th62]

I had trouble getting my head around this type of holder as well; so, I sat in my recliner for a few nights with a drawing board and protractor and drew up a few designs to try: Looking from the top, I set the tool at 90 degrees to the holder first off, but that gave me no front rake. I tried twisting the holder to the right to get the required rake, and also setting the head to the right, it worked but access in tight spots became a problem as well as needing a left and a right as per eccentric’s holders. I also tried different head angles, the closer to vertical the better the tool held it’s edge and the meaner the head angle the better it cut. There were also some issues with access, particularly when facing. Finally, looking from the top again, I set the tool at 45 degrees to the holder and made the holder straight with a 28 degree down angle. A greater head angle meant having a very thin tip on the tool, great for cutting but not very robust. This final design works left or right, uses 3/16” x 100mm long bits (no need to shorten them) and has about 7-8 degrees front and side rake and around 15 degrees back rake - seems to be the best compromise. I made a number of different designs using both 3/16” and ¼“ bits but finally settled on 3/16” as I had plenty that size. I had intended on buying a set of diamond holders, the tool I made was only meant as a tool to compare against Hafco holders. As luck would have it. it works so well I won’t bother buying the set now. Sorry no drawings, I changed them so often they became illegible.

[neksmerj]

Hi th62,

any chance you could sit out on the balcony again and sketch up your latest tangential holder with say a side view and a plan view showing the angles.

Did you also make up a jig for grinding the tool bits? What angle did you find best for the grinding. I know, questions, questions, questions.

Ken

[th62]

Yes sure I can make a rough drawing. Keeping in mind head angles, lengths, etc, while they may suit my lathe may not suit yours. I Was making the head for a second holder today, one for a round tool bit, and oops, the dam tap broke off. Flush on one side and just the taper sticking out the other. Almost finished it too, all I had to do was weld the tail on and linish. DAM.

[jack620]

Here's a few threads on making one:

Shop Built Diamond tool bit holder - Home Model Engine Machinist (http://www.homemodelenginemachinist.com/f13/shop-built-diamond-tool-bit-holder-21442/)
Tangential tool holder for QCTP - Home Model Engine Machinist (http://www.homemodelenginemachinist.com/f13/tangential-tool-holder-qctp-21357/)
Another Reason to buy or make a diamond tool holder - Home Model Engine Machinist (http://www.homemodelenginemachinist.com/f13/another-reason-buy-make-diamond-tool-holder-10702/)
My Diamond Tool Holder - Home Model Engine Machinist (http://www.homemodelenginemachinist.com/f13/my-diamond-tool-holder-2101/)

They are obviously very popular with the model engineering fraternity. I bought one from Eccentric Engineering and love it.

Chris

[th62]

Bad qualiity I know.

[Oldneweng]

Bad qualiity I know.

Works for me. I can read it and thats all that counts. It is better quality than me "missing my post" above in the wrong thread then asking a completely ridiculous question that made no sense at all in that thread. :D

I use TurboCad, but only because I enjoy doing it. Most of my drawings are scibbled at work when I have time on my hands and would look positively awful next to yours.

I have mostly 5/16 HSS so I would scale it up to suit that.

Dean

[Ueee]

Works for me. I can read it and thats all that counts. It is better quality than me "missing my post" above in the wrong thread then asking a completely ridiculous question that made no sense at all in that thread. :D

I use TurboCad, but only because I enjoy doing it. Most of my drawings are scibbled at work when I have time on my hands and would look positively awful next to yours.

I have mostly 5/16 HSS so I would scale it up to suit that.

Dean

I did wonder if that post belonged here Dean...:rolleyes:
Good job on the holder, and thanks for the plans.

Cheers,
Ew

[fxst]

Its probably know by all tang tool owners but if you break a 1/4" HSS round milling cutter or any round HSS sharpen it as you would the square bit and use that. Fantastic finishing cutter
Pete

[th62]

Here's a new holder, this one takes 6mm round bits for roughing. I'll get a tap tomorrow and (carefully) cut a thread then weld it together and clean it up. I made the head a little longer and recessed the clamp on this one so the tool overhang is a little longer, the nose isn't quite as wide and the clamp doesn't swing down when released. Saves grinding a radius on the square bit. Hopefully I can make a start on a thread cutting holder tomorrow. Correct me if I'm wrong, but I think thread cutting bits should only have side and front rake, no back rake - correct?

[neksmerj]

th62,

Thanks for the sketches, your text description now makes a lot of sense.

Latest one looks great, keep your ideas coming.

Ken

[eskimo]

Here's a new holder, this one takes 6mm round bits for roughing. I'll get a tap tomorrow and (carefully) cut a thread then weld it together and clean it up. I made the head a little longer and recessed the clamp on this one so the tool overhang is a little longer, the nose isn't quite as wide and the clamp doesn't swing down when released. Saves grinding a radius on the square bit. Hopefully I can make a start on a thread cutting holder tomorrow. Correct me if I'm wrong, but I think thread cutting bits should only have side and front rake, no back rake - correct?


I just stick a length of 1/4 round in the Eccentrics....works for me....:D

[th62]

I use 6mm round which is a little big for the 3/16 square tool holder without using a jackup shim behind the clamp. 3/16" round would no doubt fit but doesn't allow for much shaping. To tell the truth I made the round holder partly because the square holder looks very lonely by itself, so I made it a companion.