CARRIAGE LOCK

[reel jon]

will using a 16mm square bar of aluminium across the carriage be strong enough, going to use the existing holes for the steady  that are drilled and tapped in the factory, and drop a bolt down to a locking piece under the ways, any views from you Journeymen modders are most welcome as i am an apprentice modder. I will post some pics when done   

[bogstandard]

Usually Jon, the carriage lock is built into the lathe, not as an external accessory.

Once you show us a pic of what you mean, that would be the best time to give you a bit of advice.

John

[reel jon]

me again, forgot to say its a mini lathe, i have had a go and this is the result not high precision but it seem to work ok, apart from the bolt head fouling the cross slide i didnt have the right length bolt and my time ran out a small hacksaw exercise is called for

[Darren]

I did something similar to mine and then John Bogs did something even better to it for me.

But I see your casting is different to mine, what's the other side like?

There is a pic in my/Johns mini lathe bedway machining thread.

[Darren]

Here, page 9,

http://madmodder.net/index.php?topic=627.120

[ja2on]

this commercially available carriage lock is stepped down in the centre for more clearance
http://www.littlemachineshop.com/products/product_view.php?ProductID=2977&category=1

[bogstandard]

Jon,

I do see a rather major issue with what you have done.

Because of the length of the bolt you have, that will allow the saddle to rock fwds/back, no matter how hard you tighten up. You might not be able to feel it by hand, but put a clock on there and I am sure you would see what I am on about.

If you look at Jasons commercial offering, what they have done is to reduce the distance between the bar and the underbed clamp to help prevent the problem I mentioned. Even with that, it is working on the wrong area, and even that is liable to the movement I mentioned.

I would have a look at the method I used. It does mean drilling the casting, but there is plenty of meat on it, and the final result will be even more rigid than the commercial one.

John

[reel jon]

I have looked at the one you mention several times, apart from being a tight wad, i have seen such a lot of stuff on here that i feel that to buy one would go against the spirit of modding.

[reel jon]

Once i get a bit braver i will have a go at drilling and tapping the carriage, i have seen your mod and thought it very easy to use, thanks for the pointers, it is very much appreciated.
As Benny Hill said in a famous sketch "LEARNING ALL THE TIME"

[jemglen]

John, just to clarify...

The bolt tip, being brass, presses firmly against the ways but doesn't mark it? (sorry, beginner asking  )

Presumably I could turn up a brass bolt from a bit of hex bar (thinking out loud rather actually asking!).

I'd be worried about drilling square to the ways so maybe removing the carriage and drilling on the drilling press is a better idea?

Great -- and more importantly simple -- idea  also, the commercial one wouldn't fit my lathe which has a rectangular rather than h-shaped carriage.

Jerry

[bogstandard]

Jerry,

I was only last night showing Stew some of the same types of bolts as I used on Darren's lathe, but all brass.

In industry, they are made for the same sorts of jobs we are on about. Clamping down onto precision surfaces without doing any damage,

So Sure, you can make them out of brass. But do make sure you turn the end down to smaller than the thread core, as over time the brass tip will splay out, and after a time you wouldn't be able to screw the bolt out.

Even easier, is to turn up a small slug of brass, say 1/4" long, and drop it down the threaded hole, and use a normal steel bolt on top.

John

John

[jemglen]

>>But do make sure you turn the end down to smaller than the thread core, as over time the brass tip will splay out, and after a time you wouldn't be able to screw the bolt out

Exactly the kind of common sense advice I need! 

Many thanks 

[reel jon]

 :mmr:LEARNING ALL THE TIME and at a fast rate