4-way toolpost build

[John Hasler]

I prefer square headed bolts, socket head tend to fill with chips, especially machining brass.
I have this problem with the compound attaching allen head bolts filling up with chips, have to regularly clean them out with compressed air, annoying.

That's a good point. I wish I had used square-headed bolts too. Actually I think hex-headed bolts would be better yet. I could weld a socket to a short handle.

[John Hasler]

Why not space the clamping bolts evenly?

So that each bit will have two screws on it spaced as far apart as they can be.

Steve

By using #10s I was able to put a screw in each corner plus two more per side for a total of 12. That way each side has four screws that can be used. I've been using this toolpost for years and have never had a problem with inadequate clamping. On the rare occasions that I use anything smaller than 3/8" I center the cutter under the screws with a spacer.


Looking at the various quick-change systems I notice that the tool holders are more complex than my entire toolpost but less rigid. I'm thinking of making the entire toolpost quick change and then having multiple simple one or two (or even four) cutter toolposts instead of a complex toolpost and a bunch of complex toolholders. Interrupted threads should suffice for the quick change part. I'll shim the cutters for height. I'll want an indexing system. I already have several special-purpose toolposts for boring bars.

[SteveM]

I finally finished and delivered the toolpost.

Opted for 4 screws on a side (3 for each tool for better clamping on a long tool, plus being able to grip a shorter tool). Square heads would have been better, but I was working from what I had.

A couple of weeks ago, I took it over to my friend's house installed it and took some measurements.

I purposely made it a little too tall so I could get final measurements for how much to lower it so that I would get it close to where I wanted it.

I did some rudimentary scraping on the underside for flatness. The center was making more contact than the perimeter, so I inked up the surface plate and just scraped the areas with transfer until I got contact all the way across.

The new owner has it installed on the lathe. I'm waiting feedback on how he liked it. Has to be a big improvement from the lantern post.

Steve

[Patio]

Your spacing may work well with bits for turning, but what about facing and boring bits, that will face the other direction?

[Harold_V]

The only negative of the alternate facing tools is that you generally lose one position*. The bolt spacing is quite good for both.

*In regards to lost position, if very short shank tools can be used, you don't lose the position. That's not always possible, however, and would be an even greater challenge on such a small head.

H

[SteveM]

Your spacing may work well with bits for turning, but what about facing and boring bits, that will face the other direction?

Yes, that's a downside.

The system I set up for him is that I gave him one of those compartmented boxes.

I gave him a pile of bits, most already ground to a shape, and a bunch of shims in thicknesses from 1/8" down to 0.002".

I told him that when he sets a tool to the proper height and needs to take it out, take the tool and all its shims and put them in one of the compartments. That way when he needs to replace it, there's no height adjustment - just stick it in with all its shims.

Huge improvement over a lantern toolpost.

He tried it and said it works great.

One idea for boring / facing is to make a second block with two slots for a facing tool on one side and a boring tool on the other.

Steve