Power lead screw for 7x12.

[Brian]

Had to visit my local garage today and was given a 12 volt wiper motor with its mounting bracket.
Just the thing to motorize the lead screw on the 7x12, after striping off all the useless bits I started cutting down the bracket to make a mounting.
the standard spindle is a little short so I have cut the mounting bosses back 5mm to make the spindle more assessable.

   


Before going any further I need a gear that will mesh with the change gears, so I am making a cutter (N01 module) so I can make the gear.

   

Slowly slowly Brian.

[chucketn]

(12-07-2013, 03:12 PM)Brian Wrote: Before going any further I need a gear that will mesh with the change gears, so I am making a cutter (N01 module) so I can make the gear.

Slowly slowly Brian.

Brian, is that cutter for a fly cutter?

Chuck

[Brian]

(12-07-2013, 03:37 PM)chucketn Wrote:

(12-07-2013, 03:12 PM)Brian Wrote: Before going any further I need a gear that will mesh with the change gears, so I am making a cutter (N01 module) so I can make the gear.

Slowly slowly Brian.

Brian, is that cutter for a fly cutter?

Chuck

Hi Chuck
Yes it's a adaption of the one I am using to cut the gears for the new clock. tomorrow we will see if it works? I am also making one to cut the pinions for the clock.

Brian.

[Brian]

The new gear is made from shatterproof plastic from a old boat hatch.
It runs perfectly with the original gears, so that's another part done. it just needs a adapter to fit the spindle.

   

Brian.

[Brian]

Well that's the motor fixed in place next job is to measure the amperage when driving the lead screw, then I can order the control unit.
So far so good, the gears can be changed with out disturbing the motor,
and the drive can be disconnected by shifting the front leaver.

   

Brian.

[chucketn]

Looking good, Brian!

Chuck

[Shawn]

I love the placement of the motor, I did a similar modification to my SB 9" and use it all the time. I could use the gears on the lathe itself but this is so much quieter and I'm not stuck with whatever gearing I had installed last time I cut a thread. I don't have a QCGB so setting the feed rate is a bit more involved than a couple levers. Having a variable feed rate would be even nicer. I used step pulleys but found I was using only one step 95% of the time so it has never left that postion in the past year. The feed rate leaves a nice finish and I'm never in a rush so I'm not really concerned about anything else.

I'm using what I had on hand so it's a 1/2 HP motor driving a 25:1 speed reduction drive to a pulley on the leadscrew. I bought a another leadscrew bearing for my lathe on Ebay because I couldn't bring myself to cut into the existing one. If I ever decide to remove the drive (doubtful) I can simply install the original bearing back on.





Shawn

[stevec]

Nice solution Shawn, good job!
Any thoughts of changing to some kind of variable speed motor?

[Shawn]

A variable speed motor would definitely be the way to go, I think Brian has got it right for sure. I was testing it out when I put this together. The only reason the motor is painted is because I switched it off the lathe for a 3/4hp that ran much smoother. It has worked so well I haven't bothered to change anything.

Shawn

[Brian]

That looks a mighty powerful system Shawn. I cant stop this wiper motor by hanging on to the saddle hand wheel. so yours must be great.
I wonder if it is possible to broach keyways or splines by indexing the chuck ???.
After getting the meter from the boat, I tested the draw it's 5A similar to
the motor's used on the mill table. so I will order a PWM control unit ans tap into the mill power supply.
I cant use the other end of the lead screw because I have a wheel to fine feed the saddle if I require it. one div = .001".
   

Brian.