HF central machinery 5980

This forum is dedicated to those hobbyists with the 3-in-1 metalworking machines. Mill-Drill-Lathes. Tips, techniques, modification and use of these machines is topical.

Moderator: Harold_V

Post Reply
rlrealjr
Posts: 1
Joined: Fri Feb 22, 2019 10:40 am

HF central machinery 5980

Post by rlrealjr » Sat Feb 23, 2019 7:16 pm

Looking to see if anyone know thread diameter and pitch for spindle. Looking for backplate and chuck and little machine shop has chucks but only has backplate that need to be machined to fit. Thanks for any help.

pete
Posts: 1728
Joined: Tue Feb 10, 2009 6:04 am

Re: HF central machinery 5980

Post by pete » Wed Jun 05, 2019 7:13 pm

If you have the lathe already then simply measuring the spindle threads O.D. and it's TPI or metric pitch isn't hard with even calipers. There's better methods, but caliper measurements should be close enough to identify what you have if it's a standard thread. The way things change with off shore machines I wouldn't bet on any two machines having the exact same spindle threads at all. Yes they may be the same or maybe not. So taking the dimensions from what someone else happens to own may or may not apply to what you have and when and in what manufacturer's plant yours happened to be made in. Almost all chuck back plates are in the semi finished condition. That allows you to precision fit it to the chucks exact required dimensions. Doing so is just part of owning a lathe. If it's a totally un-machined back plate then there's just more work to make it fit both the chuck and the lathes spindle threads, chuck register and flange.

spro
Posts: 7716
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: HF central machinery 5980

Post by spro » Thu Jun 06, 2019 1:26 am

One of the first things I had to do, was internal threads for a chuck back plate. I can't say it was easy but we learn so much along the way. If we can remember the travel to arrive , it was a journey worth taking. Fwiw I had many things wrong. I was grinding internal tools with the wrong rake angle, wrong lead. It gets to where you have to really understand what is going on. If the destination was easy, everyone would know the path. It is the path and that is the nut to crack. Everyone and every lathe is slightly different, so advise from afar can't be perfect.
Creative grinding of an internal threading tool may look well but we have to go with standard ways. Lot is going on with that one tool and it is forming the back while cutting the front of the thread. These edges must be near equal.
This comes down to what has been pounded into our head. SHARP ! This ain't wood lathes or work that gives with dull edges. This is steel or iron which fights you every second. It was made to be stable, hard to modify or they didn't care a bit. The tool edges must be sharp and rigid. Length of tool no longer than needed .. Then crash. That's another thing which happens. Know your machine well before that.

Harold_V
Posts: 17786
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: HF central machinery 5980

Post by Harold_V » Thu Jun 06, 2019 2:01 am

Just a comment on threading tools and rake angle.
There shouldn't be any. Applying rake alters the included angle of the thread. It is also the source of less than acceptable cutting action (because what should be the cutting edge moves below center).

Be mindful of the lead angle of the thread in question. The tool required will look strange, especially for coarse threads, due to the required relief.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

spro
Posts: 7716
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: HF central machinery 5980

Post by spro » Thu Jun 06, 2019 2:17 am

You are so cool including something else. "required relief.. for coarse threads" Worth a read or many.

Post Reply