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Thread on chinese 250-200 piston type tool post handle?

hahnpv

Plastic
Joined
Aug 18, 2019
Title says it all - I bought a Harrison L5A which came with a Chinese 250-200 (BXA) piston-type toolpost and no handle. I tried using some taps and it feels like its 11mm but I can't figure out the pitch. Angle is poor for reading a gauge. Any help welcome.

thanks
philip
 
While not getting in to the origins of your toolpost !!

A FYI - 11mm is a ''non preferred'' metric thread, and 7/16'' is very close??? ............

Might be worth a try.
 
Here is how I measure the pitch of an unknown tapped hole. I prepare a wood dowel with a diameter a little larger than the minor diameter of the tapped hole. Then I use a knife to cut the end of the dowel into a triangular shape. Screw the dowel into the hole and then remove it and measure the pitch with a pitch gage or compare to some known size screws that might match.

Larry
 
Get you a selection of metric bolts and try them until one will go. If no luck, toss out and buy a genuine Aloris tool post! Period!

Oddly enough it came with several genuine Aloris toolholders...
 
Skip the first part and just send it to the scrap yard. Piston style are worthless. At least get an import wedge style

I agree but I'd like to get cutting before buying a nicer toolpost. I tried taking the CXA off my south Bend but it was just a little too big :)
 
Here is how I measure the pitch of an unknown tapped hole. I prepare a wood dowel with a diameter a little larger than the minor diameter of the tapped hole. Then I use a knife to cut the end of the dowel into a triangular shape. Screw the dowel into the hole and then remove it and measure the pitch with a pitch gage or compare to some known size screws that might match.

Larry

Then go to ace hardware and buy the screws imperial and metric closest to what Larry's method proved and try them by hand to find the one that fits. (seems lately ACE has the best selection)

I know from China it may be a crap thread so be careful.
 
Make a handle with a nice ball end and turn the other end down until it goes in. Then J-B Weld it in place.

It probably isn't worth the time to do more than that with it. Plan on getting a better tool post when funds are available.

Or make a really good one:

attachment.php


* Rock solid: NO pistons and NO dovetails. The wrap around design of the holder makes it like ONE with the post.

* No internal moving parts.

* No tools needed to change tool holders. No wasted time by searching for that wrench.

* Flat out the fastest quick change of any tool post. ANY! In a commercial shop time is money and this tool post saves time with a single motion to mount and dismount a tool holder. A tool change can be accomplished in 3 seconds or even less.

* Repeatable to well under 0.001".

* Independent adjustments. Tool height adjustment in every holder with no locking nuts. Just adjust with an Allen wrench and you are done. It holds the adjustment. So that is really fast too.

* Easily scalable to any size lathe.

Quick Change Tool Post for Lathe - HomemadeTools.net
 
Simply take a 5/16 bolt 5" long (TSC grade 2 will be fine) Hold it jammed in the hole,
and glom some weld on it using a HF gasless 120volt mig.
 
Don't let folks beat you up too badly having a piston style tool post. First of all, it is what you have now. Secondly, they are not what I would consider complete crap. I have a piston style on my old SB 9 and it works pretty good. Is it the best? No. but it gets the job done when I use the SB on rare occasions. Heck, when I bought the lathe forty five years ago it had an Armstrong holder on it and it still made good parts.
 
The only reason for threading the handle on, is for cheaper shipping.
So welding it is just fine.
 








 
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