Simple Carriage Stop

[Wongster]

The progress of making the stainless steel bushing for my dad was a slow one. Especially with the turned lathe being some time too long and some time too short. I went to the various sites again to look at the carriage stop implemented on the mini lathe, hoping to find one simple one to make for the Proxxon. Decided to just make a clamp out of some aluminium block together with the clamp plate from the Fixed Steady Rest.

I do not have aluminium stock of the right size in my box and so most of the time was spent cutting and milling a bigger piece into rough dimension.



This one is flawed. The cap screw head is too tall. Even if I counterbore the aluminium piece to cater for it, I'm still not able to get under the chuck to tighten it when in position.



Replacing with the Hex Head solved that problem.



I carried on working on the bushing and was happy about what I did till a long string of swarf got between the carriage and the stop. I tried using a small piece of card to cover the gap but still allow a portion of the gap visible. Need to know where to stop the power feed and manually complete turning to the shoulder.

This proved unsatisfactory as the card kept being pushed out of the way by swarf. Time to complete the carriage stop like those pics I saw.

I have a piece of 8mm diameter aluminium rod which I shortened for the carriage stop. The stop was drilled through followed by a tapped hole to hold the rod in place.





The smaller surface area of the rod acting as the stop lessen the chance of swarf coming in between. With that done, I carried on and completed 3 pieces of bushings. At the beginning, I actually wanted to have a micrometer of sort to use as an adjustable stop. The one I bought sometime back is too long to fit. Without it extended, the carriage stopped too far away from the chuck. I'll see if I can get a shorter one, hopefully with its stem at 8mm diameter. Save me the trouble to make another piece of the block.

I had a fun day playing with the mill and lathe. I'm able to use all my endmills now with the ER16 collet chuck. I also bought the keyless drill chuck which is such a beauty to behold. I didn't believe that by merely tightening the chuck by hand that the drill is locked in place, strong enough for drilling and even tapping (by hand of course, with the chuck serving as a guide). I drilled up to 8mm without an issue (started with 6mm drill followed by 8mm).



The X axis scale really helps! But I still count the turns in case I've some play in the bracket holding the read head. I stick the display on a bookend bent backwards.



That's all for today. I'll be going back to work tomorrow though I'm on 10 days medical leave. Fixed up a couple of appointments end last week. Couldn't find someone to take over. Its ok, I'll take the opportunity to pop over to the tool shop to buy one or two more machine light with magnetic base in between appointments.

Blessed day!

Regards,
Wong

[Highpower]

Well, there is no stopping the wongster now folks. He has been bitten hard by the machining bug, and it is really showing. Better hide your raw materials...... there is a metalworking monster on the loose around here. And he's hungry!

Seriously though - great job Wong. Keep up the good work.

[Wongster]

You just gave me a , Willie!

But that's if anyone here is living in SG. I'll advise getting your machines all chained down and locked.

Really, thanks for the encouragement.

Regards,
Wong

[Highpower]

(07-25-2012, 10:14 AM)Wongster Wrote: You just gave me a , Willie!

But that's if anyone here is living in SG. I'll advise getting your machines all chained down and locked.

Regards,
Wong

[TomG]

Looking good Wong.

I would make a couple of suggestions though on the design. You may want to consider centering the stop rod and threading it rather than rely on the set screw and use a jam nut to lock the rod in place. Centering it would also make room for two locking screws (closer to the ends where the clamping happens) so there is no chance of anything moving when it gets bumped by the carriage. Moving hard stops tend to ruin your day.

Tom

[Wongster]

Tom,

To make sure I understand what you wrote. You mean to thread the rod and drill & tap the hole in the middle? If that's the case, should I use a screw with the head cut off instead if threading the rod?

Regards,
Wong

[dallen]

(07-25-2012, 11:00 AM)TomG Wrote: Looking good Wong.

I would make a couple of suggestions though on the design. You may want to consider centering the stop rod and threading it rather than rely on the set screw and use a jam nut to lock the rod in place. Centering it would also make room for two locking screws (closer to the ends where the clamping happens) so there is no chance of anything moving when it gets bumped by the carriage. Moving hard stops tend to ruin your day.

Tom

specially when they keep getting progressively shorter and you don't notice till like the tenth part

[Mayhem]

Hey Wong,

I took Tom's description as moving the stop to the centre and you can use a bolt with the head on. In fact it would be better with the head on, as you can hold it still whilst tightening the jam nut. Essentially, you are copying a gib adjuster or the tappet adjuster on an engine - just a little bigger.

The other suggestion was to place two clamping bolts, rather than the single one you have now. These are not the small bolt you currently have locking your stop, but the one that holds the actual aluminium bar to the lathe. Having 2 bolts (close to each way) will give better clamping and less chance of it moving that a single central one.

Here is a real quick and dirty sketch that may help (not to scale or convention etc).


  Untitled-1.jpg (Size: 35.21 KB / Downloads: 131)

[Wongster]

Thanks for the sketch, Mayhem. It doesn't look quick (not if I'm to do it) and definitely not dirty... I was expecting a photo of a small piece of paper, full of grease stain, with hand drawn diagrams...

I'm thinking of using M6 clamp bolts and M8 bolt as the stop rod. Want to reduce the height if possible. Otherwise, I can only turn small diameter parts if I want to use the stop.

Regards,
Wong

[Mayhem]

I'd probably want to go with M8 CHS for the clamping bolts. The aluminium is thick enough to recess the heads into. Also, as they are closer to the ways and not directly under the centre of the chuck, you should have sufficient room to fit and turn a hex wrench.