thru boring a 6" chuck for direct bolting to rotary table

[old mart]

I have one of this type, made in Italy, it cost me about £20. Mine has only the triangle insert, a TCMG, I think. For seating MT tooling like drill bits, I use a copper hammer which sits in the lathe tray all the time.

https://www.carbideanddiamondtooling...T-340W-ID-3061

[Bill White]

I did buy an Iscar 1.25" 45 degree facemill and went thru several inserts before finding the right ones- that leave a mirror finish. It takes 3 inserts. Found them new on ebay but they were still $50 - more than I paid for the mill second hand. But veery happy with it. I will look on ebay for resharpened carbide. My cutter drawer is half from ebay and the deals Ive found still make me smile. ($300 Niagra 5/8 corner rounding end mill- $30, never used that I can see) I'll look into the APMT inserts that sounds like a real good tip. You had me at cheap inserts bc they can get pricey.

This is what Ive been at all week. 4 of these things as prototypes me and my partner are trying to get a provisional patent on. Making something for the for the first time is slow going.

[Bill White]

Hey I want a carbide countersink too! I was using carbide lathe bits (inserts) and they cut well. But everyone says HSS cuts alum/brass/plastic as well if not better so I have stuck with HSS to save $$ bc I dont work much steel except for my own tooling. But I am doing that more often now so the time has prob come but I'm def staying FAR away from the $419 variety chamfer tools ;-)

[old mart]

I was very lucky to get that adjustable countersinker for 1/20th of its list price, I get quite a lot of bargains because I am retired and have the time to scan the latest stuff that is listed on ebay. It has its limitations, the maximum chamfer is about 1 1/2" diameter and the smallest is about 3/8". A chamfer cutter could be held in a boring head for milling larger sizes, or a HSS one could be ground up to fit. The link is for one of the cheap shell mills which take the cheap APMT or similar inserts which also come in sharp aluminium grades.

https://www.ebay.co.uk/itm/362986811...Cclp%3A2334524

[Bill White]

I looked at that cutter before I got my Iscar - the price is amazing and I hear it works well. With my small rockwell I'm not sure how much power 4 inserts at 90 degrees need. I notice my collets get pretty warm not so they burn your hand but good and warm. I'm not sure how hot a mill should be. I'm gonna search for APMT insert end mills - those prices are up my alley.

[old mart]

I use shell mills up to 80mm in two mills, one has 1 1/2hp single phase and the other 1hp three phase. That size is usable as long as you don't expect to run at commercial cutting rates.

[Bill White]

At that price I might try one out, but my Rockwell is 3/4 hp- it has VFD, but I usually just change belts. a 2 or 3 inch would be nice for light finish passes.

[old mart]

One of the cheap shell mills with inserts for aluminium would work well using very light depth of cut in steel, say 0.004" max. The aluminium grade inserts work well for finishing cuts when lathe turning, you can even run at 0.0005" depth of cut, where inserts for steel would just leave a messy surface.

[Bill White]

I'm gonna make a note for that. I knew they would cut steel but that gives me a starting point. Thanks Mart

[old mart]

The aluminium grade inserts need handling with care when used for finishing cuts on steel, but I got away with using one when boring soft chuck jaws, and thats definately an interrupted cut. I was milling using a Kennametal fix perfect 63mm shell mill with the polished inserts for aluminium, and managed to skim about 0.002" DOC across part of the jaws of a Bison vise. I did think about running right across, but the inserts were expensive, so I chickened out. The inch that I had cut looked like a mirror. Those jaws were too hard to file.

[Bill White]

I thought you could file metals that were too hard to mill? Altho with carbide prob not true, then again diamond files prob is true. I have worked mostly with soft stuff but i'm having trouble understanding. I'm sure its my problem but I do see where making chuck jaws would be an interrupted cut. But when you say jaws for a vise I get lost. If your taking a skim cut across the steel of a vise jaw thats a (flat) 4 or 6" cut- why would you not continue the cut from one end to the other?

I'm asking bc I want to make jaws that are V notched one horizontally and one vertically to hold rod stock in either axis. I'm thinking to buy just machinable steel from Mcmaster for this . Curious about what you where doing here and why.

[old mart]

The Bison jaws are case hardened, and the cutter hitting them was my f-u. If I had run right across to clean up my mistake, the expensive Fix Perfect carbide inserts might have been ruined.

Today, I milled a scallop out of a hardened 4 way toolpost base to give extra clearance. The milled bit is immediately above the hole and was made using 16mm ball nosed solid carbide end mill made by Kennametal.

[Bill White]

So when you are milling that scallop, do you plunge or come in from the side in stages and then true it up by plunging?

[old mart]

The toolpost would only fit in the vise on its side, and with a vertical mill, I used the Y axis. I started with a second hand 6mm solid carbide and took off about 1/4 mm each pass as I wasn't sure if the steel would cut. When I had got 2mm deep, I thought I would chance the 16mm Ball end Kennametal and also took small cuts. Both cutters look undamaged, so it was a good result. The 6mm was bought used and cost less than 50 pence, so it was ok to use as a guinea pig.
I have been testing a 50mm shell mill which uses square inserts. The inserts are for aluminium and are very sharp. Used on mild steel, they work very well as long as you have the patience to treat them gently. I was pleasently surprised to find that the inserts stood up to steel very well, and arestill on the first of their 4 indexable positions. I dont think they would be suitable for harder steel except for a fine finishing cut.