Thread cutting problem on an AI Hembrug

Good evening to you all!

I have a little problem that I haven't solved yet...
On my AI Hembrug is a handle that does not do what it's supposed to do.
Is there any body who can help me with explaining how it works??

When I push down the handle, or pull it up, nothing happens
I want to cut some inside threads in a steel bus.
It's over 30 years ago since i've done that so have to learn again.

The left handle is for automatic feed, the middle is for threadcutting. Correct me when i am wrong!
The problem is when the lath is turning and I push the handle down, or pull it up, nothing happens, the chisel stays at it's place.

I have pulled the whole handle out of the lathe, and I think it's a conical setting.
When you push the handle, the conical ring pushes again the inside of the sprocket and so you have a connection, at least I think that's what it should do.

Can someone explain to me what could go wrong, or what I am doing wrong?

I am talking about the handle with the black ball.



Thanks for helping!!

Best regards,

Kees

Hello Kees,

normally on AI lathe the left handle is for thread cutting and the centre handle is for the automatic feed.
you confirmed this by mentioning the conical clutch part which engages the leadscrew to the longitudional or cross feed.
the lay-out of the levers is nearly identical to the DR1S, I once owned.
leave the centre handle in it's mid position and try to move down or up the left handle. if the feed handle is not in it's idle position engaging the half nut is not possible.

good luck with your next attempt

Bertus

At the school I worked at, we had several lathes. Only one, a Jet, had the threading half nut engage lever on the left of the apron. It looks like that is the setup in your picture. And as Bertus mentioned, the feed lever position is fussy; a little off center and the half nut lever will be locked out.

So, I was wrong...
The left handle is for threadcutting and the middle one is for automatic feed then, yes?
This one works with the half nut, you can see it (left handle).

Then the automatic feed is not working. If you move the handle up or down, nothing happens, idle position is good, maybe not in this pic, but it is good.
If you engage the left handle, the middle one is blocked, and vice versa, so that works allright. If one of the handles is engaged, you can not engage the other one.
Oh, I only have longitudional feed on this machine.

How do I get the automatic feed to work again?
I had got it out of the lathe, and the sprocket also, you don't see any wear on it....
Someone has an exploded view picture/drawing of this part??
I can make pictures of the parts apart if this helps?

Thanks for your replays!!

Kees.

Generally, on a lathe equipped with both a lead screw and a feed rod, when the leadscrew is rotating, the feed rod is not and if the feed rod is rotating, the lead screw is not.
Just looking at the photo in your first post, I can't see a feed rod so will assume that the leadscrew is your only method of motive power to the carriage.
If so, I would jiggle the center lever up and down with the left lever (thread) disengaged to see if I could get any motion.
The lead screw will have to be turning regardless of whether you are turning or threading.

AI Hembrug has a slot all along the lenght of the leadscrew so it dubbles as a feedrod

The manual you can download from that frens forum passion- usinages mentioned in the manual section on this board
Hembrug AI DR1

If you want any manual it is wise to first check this forum
It has hundreds of manuals available

Peter from Holland

Thanks guys!

I have a manual, only that is for a newer type AI, it has not the same carriage as mine.

The leadscrew has a slot over it's full length....can you explain the "dubbles a feedrod" Peter?
What Bertus says is correct, I think, I just can't get the feed handle to work just yet. The halfnut for threadcutting works fine (the left handle).

Greets,

Kees

Kees

The manual in the link has a drawing for both the machines with and without crossfeed

a feedrod is a rod with a spline The leadscrew is a very course threaded spindle (trapezium draad)

In general the leadscrew can be directly connected to the carriage by means of the half nuts
The feedrod powers a worm which then powers a wormwheel inside the carriage that powers a geartrain that finaly powers the gear that is riding in the gearrack at the underside of the bedways All this has a clutch (and with a crossfeed a selector) wich isn!t working on your lathe
On a AI Hembrug the leadsrew has a spline over its full lenght So it is 2 functions in one part

Peter from holland

The two functions are then threadcutting AND automatic feed, that's all? I was thinking to difficult

I have downloaded the manaul. This one's more extensive as the one I had, thanks for the tip!
Looked at the drawings but that could not explain my problem.

The clutch is the one that must causes the problem...it has worked a while ago.
I will try to pull it apart from the carriage and have a look.
Hope it will come off without bolting the whole carriage apart.

I have done what I had to do on the lathe, so now it's trouble shooting time

I will keep you posted (could be a while thou).

Thanks for all your help until now!!!

Best regards,

Kees