A2Z Quick Change Tool Post Review

[jhearl]

I recently purchased an A2Z quick change tool post (QCTP) set from Little Machine Shop for my Sherline lathe. The package arrived this week and I got around to installing it last nite. Installing it is straight forward - simply remove the extra-long T-nut from the Sherline tool post and use it with the new QCTP. I ran into a problem right away, however. The tool post (held in place with a long cap screw through the center of the post) would not tighten down on the cross slide table. I wound up having to put two fat washers under the head of the cap screw to make it tight.

 

Next, I mounted a 1/4" square cutting tool in one of the holders provided. The holder is designed to hold tools from 1/4" to 1/2". (Note, the website says that although you can get a 1/2" tool in the holder, it may not go low enough to allow it to be centered on the work. I don't have a half-inch cutting tool, but it appears that it would work just fine.) I put the tool holder on the tool post and, using Sherline's height gauge, attempted to adjust the height of the tool. Unfortunately, it would not come up high enough. It was about 1mm shy. At that point, I began suspecting that the tool post was simply too short so I initiated a series of emails with Little Machine Shop. I got a prompt reply from Roger Proffitt who said he hadn't heard of this happening before. I asked him for the dimensions of the tool post so I could check to see if my had been milled too short. He measured another tool post he had in stock and mine was the same size. In the end, the best he could offer was for me to shim the tool post or the cutting tool or return it for a refund. I like the tool post and wanted to keep it, so I decided to make a shim to go under the tool post itself. I had a piece of 5/32" brass plate I was able to cut down to size and drill a hole through it. I glued it to the bottom of the tool post with super glue and now the tool post sits tight on the table and I can adjust all the tools as needed. It's a bit disappointing to have to modify something that is supposed to be made specifically for your lathe, but it is what it is and it will work just fine now.

 

In this picture, you can see the brass shim under the tool post:

 

And here is a view from a different angle:

 

As for the tool post itself, I like it a lot. It is designed so that the tool holders have a dovetail slot that fits over a dovetail on the tool post. Rotating the arm on top of the post pushes a pin outward that then pushes the tool holder against the dovetail. For a small lathe like the Sherline, it seems solid enough to me. Changing tool holders is, indeed, quick and easy. There is a dovetail on the left side of the tool post and one on the "back" (that is the side away from the operator). To angle the tool post on the table, you loosen the cap screw and turn the whole tool post. Each tool holder has an adjustment knob that raises and lowers the tool holder on the dovetail. Once you set the height for a tool, you can lock the adjustment knob so you don't have to re-set it unless you were to grind the tool or replace the cutter. The set comes with 4 tool holders - two for standard, square cutting tools, one for a 1/2" parting tool, and one for a 3/8" shank boring tool. Additional tool holders are available.

 

I also bought a blank tool holder ($13.95) that can be milled in any way you like. My idea is to make a holder for the tool rest used with wood turning tools. Although I looked at it a while this morning, I have yet to figure out how to make it work. Clearly it's going to take a bit more thought.

 

The QCTP with a set of four tool holders sells for around $100 and it was worth the price to me. There are sets available for other mini-lathes as well. It took about a week to arrive and shipping was $12.76. Making the shim was no big deal and the tool post works great. Standard disclaimer - I have no connection to Little Machine Shop other than being a satisfied customer. Here's a link to the page for the Sherline version - http://littlemachineshop.com/products/product_view.php?ProductID=2477&category=-419988835

 

Cheers -

John

[jhearl]

I just thought I'd follow up since I figured out how to mount the holder for the wood turning tool rest to an A2Z holder.

 

First, I milled a slot in the bottom of the A2Z holder the thickness of the Sherline part. Then I drilled and tapped two 10-32 holes so I could mount the Sherline part to the A2Z holder (it needs to be switched from one side to the other depending if you want the holder parallel to the stock you're turning or perpendicular for end turning).

 

 

The tool rest slides down into the Sherline part, which is resting on the cross slide table. Here, you can see the Sherline part attached to the right side of the A2Z part for turning parallel to the stock:

 

 

To face turn, you have to unscrew the Sherline part, move it to the left side of the A2Z holder, then mount the A2Z holder on the back side of the tool post.

 

 

If you need to face turn a very small object, you might be able to simply rotate the tool post 90 degrees and move it to the back of the cross slide with the wood tool rest set up for side turning but the tool post would mostly be in the way of your turning tool. Still, unscrewing the Sherline part only takes a couple seconds, so it's no big deal.

 

I have found that I really like using a metal cutting tool bit to round off wood stock but then want to switch over to a wood turning tool for shaping, so this QCTP makes that very easy. I've also found that wood turning tools can be used on brass, so it's nice to be able to turn the brass to the desired diameter then switch to a wood tool to do curves.

 

I think I'm going to be very happy with this setup.

 

Cheers -

John

[gjdale]

John,

 

An interesting review - thanks for sharing. Can I ask why you opted not to buy Sherline's own QCTP?

[mtaylor]

John,

 

I don't have those brands but it does seem to be a not uncommon issue.  I use shims under the tool rather than the whole post as I use some 1/4" and some 1/8".  I also have some 3/16" tool grade bar stock that I'll be making into special shape tools.

[jhearl]

Two reason's I didn't buy Sherline's version. First was price. They want $260 for their set with just three tool holders. And, if you have any 3/8" cutting tools, you'd have to buy an additional holder for $65. Second, they don't offer any sort of holder that I could modify for the wood tool rest.

[bizibilder]

It is quite normal to have to shim lathe tools.  You have put the shim under the toolpost itself whereas it is more usual to put the shim under the lathe tool in the holder itself.

 

Firstly the 5/32" brass plate shim, as you have it, adds two "mating surfaces" to the set-up and may lead to the toolpost twisting under load if it is not tightened sufficiently especially if any oil or other lubricant (even wood dust!) gets between the surfaces.  If you put the shim under the tool it is held by the side of the toolpost as well as 3 or 4 clamp screws and is very unlikely to move at all - the main post can swivel on its central screw.

 

The reason you need the shim with the thinner tools is that the manufacturer has had to make the system work for tools up to 1/2" so, if you are using 1/4" tools you will have to "find" that extra 1/4" (actually usually a bit less) to make up the difference.

 

By the way - "posh" Quick change toolposts usually have a rachet wheel bolted to the slide underneath and a pawl mounted under the toolpost itself.  Thus you can only rotate the QC post in one direction and it will "click" round (usually eight times per revolution) in an anti-clockwise direction (viewed from above).  The tool post cannot turn under normal load - ie cutting toward the headstock.  It is unfortunately unlikely that this refinement will be found on these tiny lathes that we modellers use at the prices we are prepared to pay!

Edited September 6, 2015 by bizibilder

[jhearl]

Bizbilder - thanks for the info on shimming. I see your point about the rotation. The original bottom of the tool post is also pretty slick (hard anodized) and in the instructions, they say that if the tool post rotates when you lock and unlock it, you should put a piece of copier paper between it and the table. "The paper shim engages the pores in the surfaces and locks the post in place eliminating the issue." I did, by the way, super glue the shim to the bottom of the tool post so there won't be any additional mating surfaces that could slide against each other.

 

Also, while I could have shimmed the tool, there was still the original issue of not being able to tighten the tool post on the table without either adding a couple of fat washers under the head of the cap screw or maybe cutting the cap screw down to a shorter length. For me, shimming under the tool post seemed to be the best option to solve both problems at once.

 

Definitely no ratchet wheel on this tool post and as you say, not likely to be found on small lathes but I suspect the forces aren't so large as to require it either. I'm not intending to cut steel with it - just brass and wood. The Sherline tool post has a T-nut and angle bracket to lock down the tool post in addition to the screw through the center to stop any rotation. We'll see if it becomes an issue when I start to use it. I confess I haven't even tried to cut anything yet with the new tool post in place.

 

Cheers -

John

[panofish]

I just installed my QCTP from A2Z on my sherline.  It was purchased months ago. 

I had exactly the same experience as you.  The toolpost is about 1/4" too short and the mount bolt is about 1/4" too long.

My solution was to shorten the bolt.  Then when I put a 1/4" tool in the holder... I added another 1/4" tool blank below the tool.  The 4 lock bolts work fine to hold it in place.  A 1/4" tool placed on the lower edge of the holder is too low and won't work.  Perhaps a 3/8" or 1/2" tool may work... I haven't test yet.