Yet another CTC boring head question.

[Anorak Bob]

Some of you blokes probably own one of the above. Do you reckon it would be possible to machine off the existing 1 1/2" x18 threaded section and recut the thread closer to the feed screw, maybe close to where the chamfer around the dial starts?



I know I can cut down the arbor by about 10mm and remachine the thread. I tried my hand at it a while back when I mounted my little Craley head on a CTC arbor. I removed the entire projection forward of the flange.





I probably don't need to explain why I would want to do this.

BT

[Jayson]

Hi Bob,

I'm not sure I totally understand the question but maybe this will help,

the pocket containing the threads for the arbor is 12.5mm deep and that comes to here on the head:

Attachment 198927

The threads stop about 5mm from the bottom of the pocket and then the pocket steps in to clear the threads. I hope this makes sense.

Attachment 198928

Let me know if you need other photos as I am a little vague at this time of the day.

Regards,

Jayson.

[Anorak Bob]

Thank you for your reply Jayson.

The reason for asking the question was to try and find out if it would be feasible to reduce the overall length of the boring head by cutting away some or all of the threaded pocket and remachining the pocket closer to the feed screw. The mill that I own has a small working area. Spindle nose to table is 248mm. The combination of CTC head and 30 taper arbor, unmodified, would consume too much of the available space.

BT

[simonl]

Thank you for your reply Jayson.

The reason for asking the question was to try and find out if it would be feasible to reduce the overall length of the boring head by cutting away some or all of the threaded pocket and remachining the pocket closer to the feed screw. The mill that I own has a small working area. Spindle nose to table is 248mm. The combination of CTC head and 30 taper arbor, unmodified, would consume too much of the available space.

BT

I figured it was to create extra headroom. I have not responded as it's out of my level of expertise....

Good luck!

[Dave J]

Hi BT,
I have a Taiwanese one which is similar to the CTC one but I don't think you will get much more, maybe 20mm max, because you still need the internal thread to miss the lead screw. I am going down the shed now so I will check, mine is a 75mm boring head.

Dave

[Poloris]

The easiest way to gain a lot of room under the spindle is to fit the arbor alone into the spindle. Then you can screw the boring head in individually.
Not a problem with separate components.

Mark

[Anorak Bob]

Maybe I'm just dull Mark.

Any chance of explaining how what I'm doing is any different to your suggestion other than my tightening of the two components off the machine?

Bob.

[Poloris]

I assumed you had a problem inserting the arbor and boring head into the spindle because of the combined length and the distance between the spindle and your workpiece.

Inserting the components separately would not make a difference during use, but it may mean you don't have to move your workpiece to set up the boring head. (Not a problem if you have a DRO)

If that is not so, and I have misunderstood the problem and my post is not relavant.

Mark

[Anorak Bob]

I assumed you had a problem inserting the arbor and boring head into the spindle because of the combined length and the distance between the spindle and your workpiece.

Inserting the components separately would not make a difference during use, but it may mean you don't have to move your workpiece to set up the boring head. (Not a problem if you have a DRO)

If that is not so, and I have misunderstood the problem and my post is not relavant.

Mark

Thanks Mark.

I can't tell you how many times I have encountered the problem you describle on both my Hercus and Schaublin mill. It is extremely frustrating to painstakingly set up a workpiece only to find out that you can't swap or install a cutter. I will often unscrew a collet nut entirely to remove the collet and cutter because of a lack of room.

The original post was about reducing the room that an unmodified arbor and CTC boring head would occupy. Anything to gain a few extra millimetres.

Bob.

[Abratool]

This last week I purchased from the UK a small 40mm,,,, 1 1/2" boring head.
It comes in a kit with a bunch of 5/16" HSS cutters a boring bar to accept a 3/16" HSS toolbit. A 3MT, 2MT, & 1/2" parallel shank adaptor.
Today I spent time evaluating it, & all looks good.
For a long time now Ive been after a small boring head to suit my Hercus mill, & this little boring head seems to have fulfilled requirements.
The Hercus Mill when fitted with the Vertical Milling Head as Bob has mentioned limits the amount of vertical or "daylight" space.
Additional to the suitability for the Hercus Mill I intend to make a small hardened 60 degree centre so that the head can be used in the Tailstock with the 2MT adaptor for offsetting in taper turning, thus preserving the accuracy of the tailstock setting rather than fiddling with it.
So all good !

[Anorak Bob]

BEIGE Bruce! I will post over a tin of green paint.

[Anorak Bob]

The Chronos head is a fair bit smaller than my Craley head. Do they offer a metric version?

Maybe I should hold off on the paint till after I paint mine.

BT

[Abratool]

They do have a metric head, but were out of stock at my time of ordering.
This did not concern me because "Oldies" tend to stay with imperial
Yes, the Mill is very Beige, a bit like my era.
Im happy to leave it in the Beige state as that was its original colour.
Its like a bit of old furniture, I dont want to change its "Patina" with its battle scars.
I did touch up a Hercus Indexing fixture purchased second hand on Ebay. It arrived Black. The colour match to the lathe was not quite Hercus Green but a bit better than Black.
regards
Bruce

[Anorak Bob]

Yes, the Mill is very Beige, a bit like my era.
regards
Bruce

Your era. Spose there's a couple of safari suits hanging in the robe ..

[Abratool]

Here are a couple of photos of the Hercus Beige Model O Mill
Bruce
ps
Im finally getting to understand how to copy photos without increasing the blood pressure