Little boring help plz

[Piero]

Struggling to bore this hole in a part I am making

Ideally I'd like to do this in the lathe but my poor colchester bantam simply has not got the swing I'd need

I've tried my German boring head but with a 80mm hole to bore. Pluss boring head. It's all a little to much for the MT2 I have on my mill. And with such a long stick out from the spindle I am getting to much chatter

I was thinking about a reamer but this needs to go all the way through in order to reame to the bottom. I'll have to pack the block to the depth of the reamer and I'd have to have the reamer in a extension.

All a little to much

Does anyone have any ideas plz

The size I need to hit is 22mm dead. And the block is 80mm thick

 

[Shox Dr]

Do you mean there’s isnt the room to get it all in

 

[Shox Dr]

Could you not clamp the material to the Colchester cross slide with the tooling in the chuck

 

[gaz1]

his other reference is boring bar using the cross slide on the lathe or milling machine

 

[ronan]

You should be ok with the boring head, if you are getting chatter you are probably running it too fast.

 

[mtt.tr]

Have you considered a rotabroach to do most of the rough cutting then go boring head.


Miss read i thought you want an 80mm bore.

 

[Shox Dr]

his other reference is boring bar using the cross slide on the lathe or milling machine

Its what I would do with a big boring bar in a 4jaw.

Its how I started off boring out the tailstock on the M300 to sleeve. Too much stick out was causing chatter so I line bored instead.

80mm will be fine


(Linky to tailstock line boring) can’t believe that 7yrs ago

 

[rikrobson]

what about a 22mm reamer?

 

[Piero]

I ran the boring head dead slow. There was simply to much flex from the mill spindle to the actual cutting bit in my boring head.

I did think about attaching it to the cross slide on my lathe.

How do you accurately bore.

What sets the bore diameter ???

 

[mtt.tr]

I ran the boring head dead slow. There was simply to much flex from the mill spindle to the actual cutting bit in my boring head.

I did think about attaching it to the cross slide on my lathe.

How do you accurately bore.

What sets the bore diameter ???

The tool offset once you have your boring diameter you measure the tool protrusion

 

[pressbrake1]

Id make a solid bar with movable cutting tip

 

[Shox Dr]

Why are you using the quill? Lock it off and use the table riser

 

[eLuSiVeMiTe]

As a non machinist I'd set the work up on the mill.
Drill a 20mm hole through. Swap it out for the boring head without moving the table then shave the final 1mm dead slow in a few passes

 

[mtt.tr]

Id make a solid bar with movable cutting tip

I have loads like that from various operations works very well.

 

[Piero]

I am locking the quill and using the table to rise into the work

I dont like the chatter I am getting.

I have drilled a 20mm hole and was slowly trying to cut the last 2mm. A little a time

I'd rather do this in the lathe if I am honest. Only my lathe does not have the swing.

I could mount a milling attachment to my lathe (which I have)

I dont like the idea of moving a cutting tip on a boring bar in order to adjust the cut

You could easily over shot

 

[mtt.tr]

I am locking the quill and using the table to rise into the work

I dont like the chatter I am getting.

I have drilled a 20mm hole and was slowly trying to cut the last 2mm. A little a time

I'd rather do this in the lathe if I am honest. Only my lathe does not have the swing.

I could mount a milling attachment to my lathe (which I have)

I dont like the idea of moving a cutting tip on a boring bar in order to adjust the cut

You could easily over shot

Its actually pretty easy with a dti to nail the size

Set the tool and cut
Measure bore dia
With dti measure current cutter amount out
Then carefully move cutter out and remeasure with dti.

Thats how ive done it, though pressbrake will know a better method of adjusting the cutter

 

[ronan]

I ran the boring head dead slow. There was simply to much flex from the mill spindle to the actual cutting bit in my boring head.

I did think about attaching it to the cross slide on my lathe.

How do you accurately bore.

What sets the bore diameter ???

There is something up Piero, i have a Tom Senior with a 2mt spindle and had no problems using a boring head for some work like you are doing. Have you the spindle locked and take the cut by rising the knee ? Also what depth of cut are you taking ?

 

[timgunn1962]

Can you not use a between-centres boring bar and mount the part on the lathe carriage?

 

[Piero]

Yes. You are probably right

But I still dont think it's good practice to have a cutter at a length of some 150 to 200 mm from spindle mt2. And unsupported at the other end.

I have two tom seniors.

The major with the quill head as per photos and a standard tom senior with a knuckle head.

I have a horizontal arbor for both

I might use the horizontal arbor to line bore.

Failing that. Turn the knuckle head to 90deg. Make a line boring arbor and support it at the other end with a tail stock. And line bore it using the full travel of the table

 

[Piero]

Tigman

I was typing as you said that.

Yes along them lines but on the mill perhaps