Question about A2Z Quick Change Tool Post…

[tmac1956]

David…

I finally opened the A2Z Quick Change Tool Post box. I did describe the lathe as a WW 8mm watchmanker lathe with a 3-way cross slide so they could do the mounting kit – which they didn’t provide as I didn’t think they would with that arrangement. When I insert the center piece and bolt, I expected to find some sort of a nut that would take the typical “Z” profile that would slide into the tool attachment slot of the 3-way. Unfortunately, there isn’t anything and the center allan bolt is actually too wide. So, I must be missing something. Any suggestions? Do I need some kind of an adapter?

Thanks!
tmac

[david pierce]

Tmac,
There should be a flat piece of steel with a threaded boss in the center. If not, you will have to make one. I took the one they supplied and machined it down. The first operation was to get the piece to the correct thickness to fit into the slot. I did this on my Taig by putting the threaded bolt through the back of an ER-16 collet into the lathe and screwing the supplied foot down to the collet face with the boss facing out. I then turned the piece to the correct thickness up to the boss on the part. Once this was done I took the foot (part) out of the lathe and put it in a vice. I then took a large double cut (roughing) file and filed the sides down until they fit into the slot. The boss was still a little too large so I worked it down with a file until it too fit into the slot. If A2Z did not supply the foot you will have to make one from scratch from a piece of square stock. The bolt that A2Z supplied with my supports fit the cross slide slots but it was close. Keep me informed.
david

[tmac1956]

David:

I think their version of the mounting kit is really just the center thru-bolt, so I’ll probably need to fabricate the interface myself. I just wanted to be sure before I start flailing away at something.

Thanks!

tmac

[david pierce]

Tmac,
The through bolt must have a threaded nut (T-NUT) that fits into the slot on the compound slide. If one was not provided go ahead and make the first one by hand so you can get your lathe up and running. Start by measuring the slot and make a sketch of a “T-NUT” that will fit into the cross slide. Brass should be ok and it is much easier to cut than steel. To make the part by hand remove the metal by any means at your disposal such as a hack saw and file. If you don’t have a drill press you can drill the hole with a hand drill. Further down the road you can make one out of steel on a milling machine. If you get the Harbor Freight mill you will not need to purchase a $360.00 drill press as it has a rack and pinion feed that moves the head assembly up and down the box column. Because it has an R-8 spindle you can use industrial quality end mill holders, collets and drill chucks. End mill cutters will not slip in an end mill holder and drill bits will not slip in a Jacobs industrial quality drill chuck. As your machining skills progress you will really appreciate this mill.
david

[tmac1956]

@david pierce wrote:

Tmac,
The through bolt must have a threaded nut (T-NUT) that fits into the slot on the compound slide. If one was not provided go ahead and make the first one by hand so you can get your lathe up and running. Start by measuring the slot and make a sketch of a “T-NUT” that will fit into the cross slide. Brass should be ok and it is much easier to cut than steel. To make the part by hand remove the metal by any means at your disposal such as a hack saw and file. If you don’t have a drill press you can drill the hole with a hand drill. Further down the road you can make one out of steel on a milling machine. If you get the Harbor Freight mill you will not need to purchase a $360.00 drill press as it has a rack and pinion feed that moves the head assembly up and down the box column. Because it has an R-8 spindle you can use industrial quality end mill holders, collets and drill chucks. End mill cutters will not slip in an end mill holder and drill bits will not slip in a Jacobs industrial quality drill chuck. As your machining skills progress you will really appreciate this mill.
david

David:

The A2Z folks asked for a photo showing the slot into which the quick change post needs to fit – they are supposed to send it to their engineer, who will hopefully get back to me.

As to a drill press, I think I’ve settled on the Mini Mill along with two or three add-ons. R8 Collet holder, etc.

Thanks for taking the time to answer my questions!
tmac

[david pierce]

Holy Cow,
A2Z needs to consult an engineer to figure out how to make a T-NUT! Are they going to calculate the moment of inertia to work out the strength charastics in sheer, tinsile, yield and torsional?
david

[tmac1956]

@david pierce wrote:

Holy Cow,
A2Z needs to consult an engineer to figure out how to make a T-NUT! Are they going to calculate the moment of inertia to work out the strength charastics in sheer, tinsile, yield and torsional?
david

david:

I spoke to the manager yesterday – she was a sweet lady, but I know she had no idea what I was talking about. Heck, the only reason I know what you’re talking about is havng spent 20 years working for a structural engineering firm. Anyway, I think the guy that you talk with there is a consultant and they are sending him the picture of the slide rest. Surely whoever manufactures and/or designs these things will have input into what I need.

Oh… on another note…

Is this the same mini mill as the one at Harbor Freight ? It looks like the hourse power is slightly less (3/4hp vs. 4/5hp) and its priced a little higher, but other than that it looks like its manufactured by the same people. But my question is does it take the R collet? The only reason I’m looking at this one is that I can get it though Amazon and get points on my card – but that’s the only reason.

http://www.grizzly.com/products/Mini-Milling-Machine/G8689

Thanks!
tmac

[tmac1956]

David:

I finally got to speak to a machinist who makes the part. It’s an additional (nominal) fee of about $17.45 not including shipping. So if anyone ever needs to know for future reference, here’s the data:

TSNDINM8 T-Nut

Tuff Nut T-Nuts Metric DIN Standard M8 (Bag of
Steel T-nut
Threaded Metric M8x1.25
Black Oxide finish.
Lifetime warranty.
Width: Neck – .378″/9.6mm, Flange – .571″/14.5mm
Height: Neck – .236″/6.0mm, Flange – .217″/5.5mm

Thanks!
Tom

[david pierce]

Tmac,
The mill in the link has a Morse Taper #3 spindle. The one you need has an R-8 spindle. This is not a trivial difference. The spindle standard was set by Bridgeport years ago and the tooling you need is more available and affordable in R-8. When I bought mine for $450.00, Harbor Freight had the Morse taper #3 machine on sale for $175.00 and I did not even consider buying it. Check with Enco, MSC, and Grizzly tools for the milling machine accessories.
david

[david pierce]

Tmac,
I hope you realize the “Holy Cow” comment was a poke at A2Z for suggesting that an engineer would be required to design a T-NUT. I also hope you didn’t call them and ask them to actually calculate these things.
david

[tmac1956]

@david pierce wrote:

Tmac,
I hope you realize the “Holy Cow” comment was a poke at A2Z for suggesting that an engineer would be required to design a T-NUT. I also hope you didn’t call them and ask them to actually calculate these things.
david

David:

Nah… I didn’t. I did talk to the guy who was actually making the T-Nuts – literally at the time that we spoke. They were all extremely helpful. However, I think my 3 way is a Wolf Jahn and the slot is much smaller than their T-Nut. I sure hope I can make it work.

Thanks!
tmac

[david pierce]

Tmac,
The one that came with my quick change was too large and I brought it down to size with my Taig lathe and a file. The entire job could have been done with a file only or a belt sander or whatever tools are available. As long as it fits into the slot and holds the tool post that is all that is required of it.
david

[tmac1956]

@david pierce wrote:

Tmac,
The one that came with my quick change was too large and I brought it down to size with my Taig lathe and a file. The entire job could have been done with a file only or a belt sander or whatever tools are available. As long as it fits into the slot and holds the tool post that is all that is required of it.
david

Well… I have a good vise, a good set of files, a Dremel, and a vernier caliper. With eight peices to the pack, I think I can modify one that will work. I’ll go back to your original post and follow those steps.

Thanks!
tmac

[tmac1956]

david:

Since the bolt of the QC is slightly wider than the vertical slot on my 3-way slide, my thoughts are as follows:

1) cut down the threaded section on the bolt needed to thread into the T-section for the slot and rethread it again.
2) make another T-section with a neck that fits the vertical slot int the 3-way and drill a hole in the neck threaded to accept the new portion of the bolt.

I think buying those parts from A2Z is wasted money because if the bolt is too fat, then the neck on the T-section is going to be even fatter.

Any thoughts?

Thanks!
tmac

[david pierce]

Tom,
Yes, cut the A2Z nut with a hand file to fit the slot. I had to do the same thing to fit mine into a Levin cross slide. I turned the thickness down with my Taig lathe but the thickness can also be filed in. When you get your Harbor Freight mill you can make your own T-Nuts.
david

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