T nuts for compound

[DPittman]

My lathe came with a bit of a mickey mouse method of holding the compound slide down. Originally it came with only two 6mm bolts that held it into the top slide base. I quickly drilled in two more bolt holes and think that was an improvement. I ran that until now.

The top slide base has a t nut channel and 6mm bolt heads work as the t nuts and there is only a very small contact area with the bolt heads and the channel surface. I noticed there was a little bit of the channel chipping out where the bolt head was catching. Of course I may have been gronking down on the hold down nuts a bit too much to ensure rigidity, but I think the very small contact area is of concern.

I decided to make some t nuts as I could not find anything commercially of the right size. Because I had T nuts in my head, that is what I made but realized that just a flat bar head would have been sufficient. The t nut channel is not wide enough for the size of a typical t nut required that would accept a 6mm bolt. By that I mean there would not be enough material to thread in the narrow part of the tnut for the 6mm nut. The channel is just over 6mm wide at the top and 10mm at the bottom.

I made new studs and turned the bottom of them down to 5mm and silver soldered them into the tnut. The material I used to make the tnuts was hard stuff and I was afraid it would not tap very well is why I silver soldered them.

I think it is an improvement and I am now less worried about busting out a chunk of the tnut channel when tightening down the compound.

When milling the tear I started with hss end mill and noticed that the material was very hard and my finish was poor and then the end mill went to hell. I put in a chinese 12mm carbide end mill and I was amazed how well it cut and the great finish it provided.

 

[Susquatch]

I was amazed how well it cut and the great finish it provided.

Looks AWESOME! I wish my cross slide had T-Slots. There isn't a year goes by when I don't have some weird job that makes me wish I could put my compound at the far end of my cross-slide. As it is, it is a fixed location that only rotates.

 

[DPittman]

Looks AWESOME! I wish my cross slide had T-Slots. There isn't a year goes by when I don't have some weird job that makes me wish I could put my compound at the far end of my cross-slide. As it is, it is a fixed location that only rotates.

I actually can't move that cross slide to the other end either as it has a pivot point on the bottom of it that sits in a hole on the top slide.

I do however have a homemade tool post base I can use with the qctp and put that wherever I want.

 

[PeterT]

That's a nice upgrade. What I discovered on my lathe was the compound casting was not exactly flat. I didn't have a surface plate but it was obvious just doing a rub off test with a sheet of glass I had laying around. I stoned it here & there, trying not to get myself into too much trouble. It made a big difference to both sliding & staying put. So the the stock machine could be a double nasty - non planar surfaces that make you want to gronk the bolts, but skinny T-nuts or whatever that concentrate all that force into a bit of CI. But sometimes this can happen when you ingest a chip between surfaces when reorienting & then re-clamping. Pays to clean it every so often.

 

[Susquatch]

I actually can't move that cross slide to the other end either as it has a pivot point on the bottom of it that sits in a hole on the top slide.

I do however have a homemade tool post base I can use with the qctp and put that wherever I want.

I'm not following you on this. And I think there is a learning in there I am missing. Can you elaborate?

 

[YYCHM]

I'm not following you on this. And I think there is a learning in there I am missing. Can you elaborate?

The compound pivot point is in a fixed location on the cross slide.

 

[DPittman]

I'm not following you on this. And I think there is a learning in there I am missing. Can you elaborate?

Not following what your not following? Craig explained the pivot point thing and here is a picture that shows the rest of what I said.

 

[Susquatch]

Ok, thanks @YYCHM & @DPittman. I get it now.

Is the pivot point necessary? Can the pin be removed?

I love the second post. That would have solved alot of my past problems. But I don't have T-Slots. I'll be taking my cross slide apart soon to mount an internal DRO Scale. I will have to look at other ways to do a second toolpost at the back.

What is that cloth looking material at the lower left? Is that a swarf shield? If so, what is the material, how is it attached, and are you happy with it?

 

[DPittman]

What is that cloth looking material at the lower left? Is that a swarf shield? If so, what is the material, how is it attached, and are you happy with it?

That is reused treadmill belting. It is held on by a chunk of aluminum bar that bolts into the existing mounting holes for the travel rest. I had it longer but it curls up and hits the chuck when getting the carriage very close to headstock. I chopped it down and it prevents a large majority of the swarf from getting near the carriage ways.
It is curling up due to the oil/coolant that it collects on it and now I keep a weight on it when not in use to li.it that curling. Is it perfect? No but it's cheap, effective and I have lots more of the belti g to replace as necessary.

I will have to look at other ways to do a second toolpost at the back.

I wouldn't be afraid of drilling and tapping holes in you slide to mount the desired accessories.

 

[Johnwa]

Looks AWESOME! I wish my cross slide had T-Slots. There isn't a year goes by when I don't have some weird job that makes me wish I could put my compound at the far end of my cross-slide. As it is, it is a fixed location that only rotates.

I have a small t-slot table that I can fasten in place of the compound on my 9” Southbend. I’ve only used it to hold work. I’ve never thought of using it to hold a rear mounted toolpost.