Member postings for Russ Bulley

Many thanks - except all Hardinge stuff seems to be gold plated when you look at the price! But I will view!

Russ

Thanks for the reply. Indeed I have been around the Feeler website and found nothing on the “clone” seemed to be all CNC.

Russ

Edited By Russ Bulley on 29/05/2023 11:20:01

I am seeking details to make (as I cannot find one to purchase) a) the metric gear bracket and b) taper backplate. Are there any UK owners who I could maybe visit to take a drawing?

Russ

Thanks for the replies so far. So Clive this is my machine

Does anyone have a wiring diagram for Bridgeport with no transformer and MEM contactors please.

Russ

M6. Great link thanks!

Edited By Russ Bulley on 05/08/2020 10:48:35

I am bushing a small steel casting made in 1929 that is very hard, the steel blunts a HSS drill in an instant. I have broken several taps (by hand) and boring the casting has been a nightmare only solved by using a PCD tipped insert - which then broke! The casting has had a hard life and could have been "work hardened"?

What specialist tap manufacturers are in the UK who can provide specialist taps for very hard materials?

Any tips for tapping, other than winding back regularly and using high quality cutting paste?

Russ

I want to say thank you to everyone for the contributions above. Very helpful!

Russ

Clive, no I rarely can as I am using suds and at high speed the overspray is terrific. Anyhow charging (9 tpi remember) into a dead end also scares me. So I was using 5 thou increments to try and compensate.

To SOD good point, but why is the tapping drill size way off the table? I still don’t understand this tolerance as all I want is a standard thread medium fit!

I will measure the tap as suggested.

All good stuff guys. So where do you obtain the true machine use data (I acknowledge SODs comments)?

Russ

This is a very useful text on square threads https://smithy.com/machining-handbook/chapter-3/page/24

Russ

So thank you for the replies. Yes always do spring cuts. And as I am using Sandvik inserts, think the form will be correct.

I did also say these particular threads were internal.

I want someone to educate me!

As I have said before, I am not a professional, learning as I go along, and have just finished 8 x 7/8” 9tpi BSW internal threads about 2” long which has taken about three days.

Now my book (British Standards for Workshop Practice - but this seems to apply to all thread forms and tables) says for nuts medium fit, the minor diameter (which I take as h on the diagram) is between 0.7328” and 0.7620” with a tolerance of 0.0292”, depth of thread 0.0711”. So, I bore to 0.740 +/- 0.003” thinking that’s in the tolerance zone, then thread to 0.071” depth, measured with a DTI on the cross slide. But then I test with a tap, and every single thread was really tight and I had a struggle getting the tap down. All are done now, but what am I doing wrong? By the way I am using a BSW insert cutter.

I have to say, even when cutting outside threads, I can never get it right, even though I use a DTI on the cross slide and I have eliminated most wear by adjusting gibs etc. What’s the secret of reading the thread data tables?

Also, if I am using a straight Vee cutter (not a profile insert) the apex of the cutter is actually at H/6 (for BSW) deeper than the bottom of the thread due to the curve. How do you get your depth correct, as you need H/6 + h as a finished height, when you have a tolerance of 0.029”!

Russ

Edited By Russ Bulley on 31/03/2020 12:29:54

Edited By Russ Bulley on 31/03/2020 12:30:16

Thanks guys. But importantly the same threads?

russ

Already joined! Oundle, Northamptonshire

I would appreciate that!

russ

Thanks for the reply. Here Bridgeport they have separate part numbers?

Private message sent. I also have M300 with all sorts of issues...

Russ

Andrew, do you have a travelling steady?

Russ

My J head had the screws missing, so I have ordered and received 6-32 screws. But on receipt the top one is fine, but the bottom one only goes in one turn indicating a different thread, which is odd. Any knowledgable people know the answer?

russ