Pump Center

[mklotz]

Definitely a handy tool to have.

In my short hobby career I've already had several opportunities where that would be helpful.

Lathe certainly, but my mill doesn't have the room.

Is there any reason that would dictate the overall length of the pump/spring center other than, I guess, the spring?

Room under the mill head is always a problem. The spring-loading afforded by the pump center isn't really needed for guiding taps. A simple swivel will work as well or better.

Look at the tap wrench on the far right in this (repeated) photo...

It's purpose-built to be as low profile as possible. The tap fits deeply into the body to reduce overall length. The pivot rod fits into the chuck so the lateral support mechanism takes up as little vertical room as possible. The collets allow it to accept a wide variety of tap sizes (though I would recommend one of the models on the left for taps smaller than #4).

 

[SAM in LA]

With all the talk about pump centers I decided that I needed one too.

I modeled mine after the one on the "Projects in Metal" website.

I changed dimensions to accommodate the material on hand.

I had a piece of Stainless Steel, I do not know any details of it though.

I turned a 3/8" and 1/2" step on the end along with a centerdrilled spot on the end.

If you noticed, the tapered end appears to have zebra stripes on it. The next photo shows the stripes better.

It took me a few minutes to figure out why the stripes were there.

My lathe does not have a compound tool rest on it so I have to rotate the cross slide to cut the taper. The stripes are the same pitch as the cross slides screw.

My guess is the screw is bent. This screw is supported by bushings and there is no thrust bearing. One of my future fixes are to make a split nut and install roller bearings and a needle thrust bearing. My repair list keeps growing.

Thanks for stopping by,

SAM

 

[ozzie46]

Sam, Grizzily 10 x 22 s seem to be prone to this kind of markings on the work. I have checked lead screw, gibs, and other things and I am coming to believe it goes back to the 2 bolt compound tighten ring instead of have 4 bolts to hold the compound

The yahoo 10 x 22 forum has people complaining about it too. So don't be in a rush to blame the lead screw. It might be something else. Just my 2 cents worth.

Ron

 

[SAM in LA]

Ron,

Thanks for the information.

I have a 1994 vintage ShopTask Lathe/Mill.

I do not have a compound on this machine. I wish I did though, it would make cutting short tapers a lot easier without having to indicate the cross slide back into square with the lathe ways.

Before I got it, it has seen a lot of use and abuse.

I have replaced the bearings in the lathe head stock and still need to do the bearings in the mill portion. The lead screws on the lathe are supported by bushings which I will end up replacing with bearings. I also plan to make up split nuts to take some of the sloppiness. Sorry the proper word escapes me at the moment.

Thanks

SAM

 

[ozzie46]

Is "backlash" the word your looking for?

I know what you mean about words "escaping you ". I don"t know how old you are but it seems they "escape me " more often as I get older. :big: :big: :big: :big:

Ron

 

[SAM in LA]

Is "backlash" the word your looking for?

I know what you mean about words "escaping you ". I don"t know how old you are but it seems they "escape me " more often as I get older. :big: :big: :big: :big:

Ron

Ron,

Backlash is exactly the word I was looking for.

SAM

 

[Omnimill]

Old thread this one but thought anyone stumbling over it may like to see this as well, looks easy enough to make:

http://www.chronos.ltd.uk/acatalog/threading_accessories.html

http://www.chronos.ltd.uk/acatalog/info_318221.html

Vic.