Model Engine Maker

Supporting => Tooling & Machines => Topic started by: petertha on April 05, 2019, 07:51:46 PM

Title: box tool
Post by: petertha on April 05, 2019, 07:51:46 PM
I thought I saw a home made design for what I think are called 'box tools'. Its held in the tail stock and cuts axially into (slender delicate) work as opposed to conventional cutting with tail stock support etc. Any leads to hobby machinist drawings or plans?

For reference I think the commercial ones look like this

Boyar Schultz box tool
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Tangi Flow Roller Box
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Title: Re: box tool
Post by: ChuckKey on April 06, 2019, 12:17:26 AM
I would think for most work in model engineering sizes it would be difficult to fit sufficiently substantial roller guides into the space available.
An alternative is a bushed travelling steady as seen here: http://www.charleslamont.me.uk/Seagull/bits_and_pieces.html#Studs
Title: Re: box tool
Post by: gerritv on April 06, 2019, 12:44:14 AM
Model Engineer during the war years (WW II) had a series on box tools.

Also Down River Tools (https://downrivertools.com/plan-sets-kits.html) supplies kits and/or drawings for various box tools. I think that the Balance Tool is what you are looking for.

Gerrit
Title: Re: box tool
Post by: petertha on April 06, 2019, 03:08:36 AM
Hmmm... travelling steady seems familiar. Maybe that's why I wasn't finding what I thought I was looking for.
Title: Re: box tool
Post by: petertha on April 06, 2019, 03:16:49 AM
Although this looks interesting too
https://downrivertools.com/5-8-shank-box-tool-drawings-instructions.html
Looks like the sliders are manually adjusted, so is the dial on top to advance the tool in-feed?
Title: Re: box tool
Post by: Jo on April 06, 2019, 07:51:40 AM
An alternative would be to get a soft MT shank and fit a brass bush to act as the support for the end of the rod being turned (this would be disposable and drilled to fit the tail of the piece being turned). Then you need to think about how you could add a tool holder say by clamping it around the outside of the MT Shank  :thinking:

Jo
Title: Re: box tool
Post by: Jasonb on April 06, 2019, 08:05:09 AM
Hmmm... travelling steady seems familiar. Maybe that's why I wasn't finding what I thought I was looking for.

You may also want to look for "running down tool" or "small diameter tool" both of which are held in the toolpost, support the work and only need a single cutting tool.

Also look for Ramon's post where he put a round bush in his traveling steady.

http://www.modelenginemaker.com/index.php/topic,7688.msg166893.html#msg166893

The box tools are better suited to machining short lengths and/or when starting with non round stock eg making square or hex head bolts, the running down tools are better for longer lengths where the guide can run on the edge of round stock
Title: Re: box tool
Post by: gerritv on April 06, 2019, 12:55:55 PM
Jasonb reminded me of these photos I kept for future use:
Title: Re: box tool
Post by: petertha on April 06, 2019, 04:18:54 PM
Ah, now we are getting somewhere. Thanks for the leads everyone.
Title: Re: box tool
Post by: Dan Rowe on April 06, 2019, 08:55:55 PM
You never said exactly what kind of work you are planning. There are several turret tools that can accomplish the task. The simplest is a hollow mill which is simply an end mill with a hole it. Hollow mills are considered a roughing tool. It would be followed by a balance tool or a box tool. A balance tool is the one with two opposing cutting bits and it is mostly used as a finishing tool. Box tools can have hardened guides or rollers. The guides or rollers are behind the cutting bit and guide the finished stock.

If you plan to make bolts from hex or square stock a box tool cannot be the first tool unless the bolt is very short as there will be no guide when the bit starts the cut into square or hex stock. This is where the pointing tool comes in handy. The pointing tool has the guide before the cutting bit. Pointing tools sometimes look just like box tools only the guides or rollers are before the cutting bit. This type would still be not much help with pointing hex or square stock. The type of pointing tool with a replaceable front guide which is simply a round section with the proper size hole for the stock is what is needed for this.

Here are the plans for a combination pointing/box tool.
https://downrivertools.com/plan-sets-kits/turret-tooling-plan-sets/1-2-shank-pointing-box-tool-drawings-instructions-285.html

Dan
Title: Re: box tool
Post by: gerritv on April 06, 2019, 10:53:19 PM
Just realized that the 5/8 tool holders will fit nicely in the generally unused boring bar holder from my AXA set. That holder has 5/8 and 3/4 hole.
Will be ordering drawings for 2 types of box tools once they fix their PayPal issues. (reported to them today)
The tap/die holders are particularly interesting to me.
Title: Re: box tool
Post by: petertha on April 07, 2019, 05:22:29 AM
You never said exactly what kind of work you are planning.

I'll grab some pics off the camera here shortly, but this particular application is a bronze valve cage. The extended stem portion is 0.195" OD X 0.118" ID reamed hole by 0.413" length. I started to notice different fits of the same reference pin in the reamed valve stem hole. I suspected the usual culprits - drifted pilot hole, something to do with the reamer, burr on the hole entry etc. Then I put a DTI on the segment before & after chamfering the corner & sure enough it developed a smidge of runout from that operation. Kind of makes sense, its applying a bending force to the end of a relatively weak segment. So I then tried approaching the chamfer tool axially vs. cross bed infeed direction & that helped. Probably what I should have done to begin with. This isn't insurmountable but it more got me thinking, maybe there is a better multi-faceted tool on extended length fiddly bits like this that work 'in reverse' to conventional internal chamfering tools. I had not realized they are sometimes called chamferring 'mills' so thanks for that.

The box tool & travelling steady is kind of another subject. More me forward thinking about making things like the valves. I already made some tester valves using conventional tailstock supported center & they turned out OK. The excess center drilled blob of material at the end needs to be carefully cut off. I used a parting tool to get most of it done between centers & then a jewllers saw to finish. same kin dof concern - avoiding bending forces at the end of a skinny toothpick. So I was more wondering out loud about better tools for applications like this.
Title: Re: box tool
Post by: gerritv on April 12, 2019, 12:43:59 AM
Does anyone have contact information for Downriver Tools? They are not responding to their contact page :-( Tried twice in 5 days.

Gerrit
Title: Re: box tool
Post by: RonGinger on April 12, 2019, 01:29:55 PM
He is likely getting ready for the NAMES show, he has always been an exhibitor there. The show is now 2 weeks off.
Title: Re: box tool
Post by: gerritv on April 12, 2019, 09:16:47 PM
He is likely getting ready for the NAMES show, he has always been an exhibitor there. The show is now 2 weeks off.
Thank you Ron
Yes, that is likely the reason. I will wait till after the show, lots to be keeping busy with as is :-)

In the meantime I found a phone number, he called back saying they are working on a fix for the PayPal errors.

gerrit
Title: Re: box tool
Post by: bent on April 12, 2019, 09:24:35 PM
Box tools are pretty neat, I will grant.  But I've always considered them a production tool, used by screw machine shops, where you are kicking out 10,000 units a day or so.  For most tasks on lathe work they seem a lot of trouble.
Title: Re: box tool
Post by: gerritv on April 13, 2019, 12:05:33 AM
I used to think that as well but looking at some of the ones at Downriver's site they are potentially useful in the often useless/unused boring bar holder supplied with AXA kits.

E.g. the 5/8" threading tools on their site will fit very well into that AXA holder. I would set it on center/centre once (align with dead centre/center in the tailstock?), lock the cross silde then I can swap out several tools with little effort. Even the drill chuck 'box tool' would work well. This seems under better control from the carriage than from the tail stock, which might not even reach in some cases.

One example of work benefitting from this setup is making studs or nuts. Not a full blown turret setup but 'close enough' for repetitive work.

gerrit
Title: Re: box tool
Post by: gerritv on April 21, 2019, 02:41:02 PM
Downriver Tools Paypal issues are now fixed, just ordered 2 sets of drawings. Looking forward to making them...

5/8" SHANK - THREADING TOOLS
5/8" SHANK - POINTING & BOX TOOL

Title: Re: box tool
Post by: petertha on April 21, 2019, 05:41:05 PM
Box tools are pretty neat, I will grant.  But I've always considered them a production tool, used by screw machine shops, where you are kicking out 10,000 units a day or so.  For most tasks on lathe work they seem a lot of trouble.

I've been watching vids of those older gen turret style machines, they fascinate me. I think what you might be saying is they are kind of a set up once (to a target diameter) & make many parts sort of thing as opposed to progressively tweaking the cutter setting analogous to how we adjust infeed on a conventional lathe? I get that. I was more thinking about the stability aspect approaching the work from the end on longer skinny aspect ratio parts & that might be more fiction or wishful thinking on my part.
Title: Re: box tool
Post by: petertha on April 21, 2019, 05:41:49 PM
just ordered 2 sets of drawings. Looking forward to making them...

Keep us posted!
Title: Re: box tool
Post by: Don1966 on April 22, 2019, 12:23:45 AM
Cool gerritv look forward to seeing your thread...... :ThumbsUp:


 :popcorn:
Don
Title: Re: box tool
Post by: gerritv on April 22, 2019, 12:42:05 AM
Cool gerritv look forward to seeing your thread...... :ThumbsUp:


 :popcorn:
Don
I look forward to it as well, I have been too pre-occupied lately with designing a Nixie-tube clock and Visser related genealogy to do much machining. Really really missing it.