Stuart No. 2 centrifugal pump - machining help needed

Many years ago I started to machine a set of Stuart No. 2 centrifugal pump castings. Due to a relocation of housing and workshop the project was interruppted for more than a decade. Now and (hopefully) finally I am back on it again. After getting familiar with the drawings (again) and sorting out what is already finished and what has still to be done I stumbled across the impeller. Right now I have no idea how to machine this casting properly. Who can help?

Thanks,

Manfred

Edited By Manfred Baer on 04/07/2019 00:24:16

A search through back issues of M.E. Should find a blow by blow description of the making of this pump. I sold a set of castings some years ago, along with the relevant issues of the magazine. Sorry I can't give any clue to the date.

Maurice

The Stuart no2 pump was the very first thing I machined on my brand new Myford back in the 1970s. I chose it because it looked easy, then struggled with the impeller.

The casting was held in the 4 jaw with the flat back facing the tailstock. It was faced off then the blind hole in the centre was drilled and tapped. The remaining machining was done with it mounted on its shaft which was held in the 3 jaw chuck. So far so good.

My problem was that I couldn't set the top slide over to the very shallow angle needed to machine the front of the impeller. The ML7 won't go beyond 45 degrees. There are various fixes for this which have been covered since then on this forum but having to make extra tooling can be quite off putting to a beginner. I solved it by mounting the vertical slide on the cross slide. The tool was held in a vice bolted to the vertical slide with the tool pointing towards the headstock on the centre line of the lathe but moving vertically up and down. The vertical slide could then be tilted a few degrees from the vertical to achieve the shallow taper. No extra tooling needed.

If yours is a Super 7 or some other make with a different top slide design, you may not have the same problem.

Andrew

Many thanks for the ideas and the information given. I have a ML10 lathe and a vertical slide. In so far I'll try the way Andrew suggested.

Manfred

Another is to clamp a bar across the bed at the correct angle, arrange a follower on the cross slide to rub against it, then feed the cross slide whilst keeping the follower against the bar with the saddle hand-wheel

Manfred

The series in ME was by Tubal Cain and was in Vol. 170 and ran from issue #3942 2-15 Apr 1993 to #3950 6-19 Aug 1993.  I've sent you a PM.

John

Edited By John Purdy on 04/07/2019 17:08:22

Edited By John Purdy on 04/07/2019 17:16:20

Good news. Due to the help provided I managed successfully to machine most of the impeller casting on my ML10 lathe. The final step to be done is to bringing the impeller fins to right size/angle. Next weekend I'll check if the top slide can be set to the position required. If not, a mixture of a provisional hand-turning rest and a guide bar set at the correct angle (as Duncan stated) could be the solution.

Manfred

Even better news tonight. On the ML10 lathe the top slide can be set to required angle for machining the impeller casting without the handles interfering.

So I was able to turn the impeller wings to the proper dimensions in a straight forward and simple machine job. I did‘nt expect that and I‘m quite happy that it worked out so easy.

Manfred

Edited By Manfred Baer on 18/07/2019 19:11:36