What are you machining?

[Kram]

Handle and key of the milling jig - last time I was unsuccesfully using mole grips.

Radiusing tool, put an m6 hole for a locking screw and turned an little 5mm by 3mm long brass spacer to go on the end to protect the chrome plated pivot.

Got it centred and ready to drill but Im aware theres only 7mm above the centre point which wont be enough unless I use a tiny bar and have clamping screws on the side. I probably tur ed the length down about 5mm yesterday.

I think best if I either raise it up 5mm, which will need a a longer m16 bolt that I dont have or want to screw cut... or I bore the tool hole to 30mm and weld a bit of bar on, which would give much better support anyway

 

[Onoff]

which will need a a longer m16 bolt that I dont have

Got plenty here. How long, what material?

 

[Kram]

Locking bolt not as effective as I thought

This will need superglue.

I may also do smaller steps. 8 to 25mm is a reasonably big jump.

18, 22, 25 steps. Did not realise tese would be so useful, have drills but they wouldnt do the intermittent cut.

Had a boring bar sleeve I turned ages ago, mild steel so ideal for welding.

Hmm the bottom protrusions are going to need flycutting or boring had. After welding I will do another cut at 45 or 60 degrees for more clearance.

If I were doing this again I would simplify it a bit using a lump of 30mm thick plate as the base with two bores, one for the pivot and another to weld in a round bar for the upright 30-50mm. 50mm would be adequate to not need the tool holder bar I am welding in now.

 

[Kram]

Alignment with a bit of ground silversteel. No noticable warping or alignment issue after welding. It looks tilted back only becuase the front is stepped.

Milled front flat.

The new protractor works well one you realise how to set it! Cut the sides for clearance and added tool clamp screws.. You can see I have gone past the weld but it should have enough stuck on for now. May get the tig out sometime.

 

[Onoff]

Alignment with a bit of ground silversteel. No noticable warping or alignment issue after welding. It looks tilted back only becuase the front is stepped.
View attachment 438849
Milled front flat.
View attachment 438851

View attachment 438855
View attachment 438856
The new protractor works well one you realise how to set it! Cut the sides for clearance and added tool clamp screws.. You can see I have gone past the weld but it should have enough stuck on for now. May get the tig out sometime.

Whatever it is very impressive!

 

[fizzy]

Modify a BT40 holder to Int40
M16 thread which I needed to drill out to fit an extension piece.
Very hard steel so HSS won't touch it. Carbide boring bar but slow.
If only I had a bigger solid carbide end mill but they are silly money.
Despite having so many lathes it's always my trusty old Colchester Triumph roundhead I turn to.
Adapter held in with special heat setting epoxy. 6000psi strength and 5.5 sq inches so shouldn't pull out. Too hard to drill to pin. Working fine.

 

[fizzy]

If it does pull out you have a serious headache on your hands.
No need to modify the holder. You can make, or buy adapters that screw in

How can you have M16 in both? Unless I am not thinking it through properly. Surely if you drill a hole deep and tap it M16 there would be nothing left of the threaded bit at the bottom? My drawbar is very long sadly and too much hassle to remove the whole air assembly.
I have left a small amount of thread at the bottom as a backup. just in case.
The epoxy I have used is awesome stuff. Never seen anyone using it before.
Heat curing. Single pack. Flows like solder. You bake it in an oven at 170C for 45 minutes or so. Much stronger than 2 part epoxies. Not cheap and has to be stored in a fridge.

 

[Hood]

I made a load up years ago for a friend to use on his mill, don't have a pic of them but do still have the 3D model.

.

Also did similar for my Beaver mill pull studs, pic on right is standard pull stud I made, one on left is the extended pull stud to convert BT and CAT holders.

 

[Hood]

Cross section of ones I made for my friend.

 

[fizzy]

Don’t drill the hole too deep. It’s a blind hole,not a through hole.Buy one from pro tool and copy the dimensions. You can make them a lot simpler. They don’t need the wasted down section or the flats.

That's basically what I did. On the next one I will try leaving the bottom thread a bit longer.

 

[Munkul]

My drawbar is very long sadly and too much hassle to remove the whole air assembly.

I have the same issue meaning I can't use those adapters either. It's not a massive amount of hassle to remove the drawbar - I assume it's similar to mine with a couple of spring rods to remove the impact gun from on top...

I never bothered because I only have 1 or two BT40 toolholders and they were cheap....

 

[fizzy]

Cross section of ones I made for my friend.

View attachment 438913

Sadly my drawbar is much too long for the inch or so of the top bit.
I need it about half an inch longer again into the bottom but will leave a bit more thread down there next time. Even a few turns should be strong enough.

 

[fizzy]

I have the same issue meaning I can't use those adapters either. It's not a massive amount of hassle to remove the drawbar - I assume it's similar to mine with a couple of spring rods to remove the impact gun from on top...

I never bothered because I only have 1 or two BT40 toolholders and they were cheap....

I did think about it but I only have 3 of these holders which I had dirt cheap on Ebay - they are nice quality ER32 so didn't want to waste them.

 

[Kram]

Very hard steel so HSS won't touch it. Carbide boring bar but slow.
If only I had a bigger solid carbide end mill but they are silly money.

Boring bar is correct choice why would you use an endmill for it?

 

[Hood]

Sadly my drawbar is much too long for the inch or so of the top bit.
I need it about half an inch longer again into the bottom but will leave a bit more thread down there next time. Even a few turns should be strong enough.

That is way too much thread, all it is doing is wasting air and time screwing it in and out. I would cut it as you never know when cheap BT or CAT holders will pop up, can never have enough holders and when I was using the Beaver I found I could have done with more than this.

Same with the Chiron, I have these but always could do with more.

 

[fizzy]

You are both right. The drawbar takes and age to screw in and out. Definitely no need to be so long

 

[fizzy]

Boring bar is correct choice why would you use an endmill for it?

I have a 16mm carbide end mill. It removed some of the thread like a hot knife through butter. The 2 boring bars I tried were on their limit. Screaming like banshees. Much easier when some of the thread was removed. I reckon 10 seconds work with a 20mm end mill.

 

[Kram]

Then something is wrong with your boring bar or the insert worn, or wrong type for the job. The screw does not look original, correct countersink angle?

 

[Munkul]

I thought the same thing too, NGL that boring bar looks clapped fam

 

[fizzy]

Then something is wrong with your boring bar or the insert worn, or wrong type for the job. The screw does not look original, correct countersink angle?

I tried the new one it was even worse. Brand new insert. This steel is seriously hard stuff. HSS doesn't even make a mark.
The fact it is a screw thread in there doesn't help either.