Cross Slide Screw Support

A few weeks ago I finished a project that I had on my mind for a number of months.  There was a lot of play in the cross slide feed screw on my import bench lathe.  This showed up as backlash in the feed screw – when you grabbed the toolpost and applied force in alternate directions you could see the entire cross slide move back and forth.  Some of it was from backlash in the feed nut itself, but most of it was between the feed dial and the support casting itself.

I tried tightening up the nuts themselves tor reduce the amount of clearance – but then it bound and you couldn’t turn the feedscrew at all.  This wasn’t the best design from the get go.

The first thing I did was modeled the entire assembly up in Fusion to get a clear picture of what was going on – and to give a good starting point for the modification: The nuts aren’t shown on the end of the feedscrew but you can see where the assembly is constrained for axial movement – at the right side on a shoulder machined into the feedscrew itself and on the left side the inner bushing of the dial.  These are just 2 plain bearing surfaces – and they weren’t machined the best to begin with.  No wonder it wasn’t the best!

I thought about doing what Stefan Gotteswinter did.  If this was my main lathe I would copy what Stefan did as it is the best solution by far.  Angular contact bearings are the way to go in this situation.  Since I’m keeping this lathe around primarily for cutting metric threads (the Standard Modern now in the shop doesn’t have a metric transposition gear) I decided to scale back the project and see if I could just stuff a deep groove axial bearing and a roller thrust washer into the space without having to modify the leadscrew, or make up a new dial.

Below is what I came up with:

I incorporated a deep groove ball bearing (6900-2RS) and a 10mm needle style thrust washer on the opposite side.  This required a new housing and the old cast iron bearing support to be shortened up.  The new housing was doweled to the cast iron block for location.  2 counter bored cap screws hold the entire assembly together.  The cross slide screw required minimal rework – a shoulder had to be turned for the bearing to sit against.  I also turned down the shoulder on the screw that previously was a bearing support.

The ball bearing is preloaded using the existing nuts.  Care needs to be taken not to overload the ball bearing as deep groove ball bearings aren’t primarily designed for axial load.  In retrospect I should have flipped the positioning of the deep groove ball bearing and thrust washer around when thinking about cutting forces as the cutting tool pushes away from the work piece.  If I have problems I can always make a new bearing housing.

The cross slide now is super smooth with no backlash due to the support.  There is a bit of backlash in the screw, but I don’t get too bothered by that on a manual machine.  It is significant improvement with not too much effort or time required.

I made a video of the entire project as well:

 

 

Tailstock Die (and tap) Holder

A few months ago I decided I had enough with using my traditional die holder in the lathe and set out to make a proper sliding die holder.  It is a very good beginner project that is straightforward to make and also is one that is exceptionally useful.

I started out with a design in Fusion.  The design consists of 3 manufactured parts, a body, an arbor, and a handle for extra leverage.  The body is designed to hold 1″ dies – a size that I have standardized on in my shop due to primarily expensive.  As die sizes climb the prices move up exponentially and due to that I generally single point large threads.  If you have larger dies the design is very easy to modify to accommodate larger dies.

 

Traditionally most people don’t use a sliding die holder to hold taps.  I’ve always started taps in the lathe using the tailstock.  If the tap is small enough I am brave enough to power tap – being sure to leave the tap a little loose to make sure when it bottoms out it slips to avoid broken taps.  I had the thought to incorporate an inexpensive ER collet chuck into the design to facilitate holding taps.  In this design the ER16 collect chuck stub is held in the end opposite to the die holder with a couple of set screws.

Besides being a pleasure to use with dies, it also works exceptionally well for small taps.  I don’t use the handle when I power tap with it – the handle is really only used for dies.  Now when you are tapping blind holes you can simply let go of the body and the entire body spins.  You can also feel when the tap reaches the bottom of the hole as the amount of force required to hold the body quickly climbs – at this point you simply let go, allow the body to spin and shut the lathe off.

Standard ER collets do a very good job of holding taps in the home shop.  You can get ER collets with an internal square that engages the tap drive but I’ve found it unnecessary for home shop work.  They are also more expensive and harder to find online – most industrial tool supply places can get them.

If you would like to build one yourself I made up a full set of drawings for the shop, and I’ll also provide 3D CAD in the zip file (iges and step):

Handle – (Rev 01), Body – (Rev 01), Arbor – (Rev 01), CAD – (Rev 01)

I also made a video the project:

 

The Future is Here: Introducing a Laser Bandsaw

A few months ago Max and I recorded a podcast where Max and I theorized on the what the home metal shop of the future would look like.  The podcast idea was inspired by the Making It podcast hosted by Jimmy Diresta, Bob Clagett and David Picciuto where they talked about what they think the future maker workshop will look like.  During the podcast Jimmy, Bob and David mentioned the idea of a laser bandsaw – something that Max and I also talked a bit about on our podcast.

A month or so after the podcast Rod Shampine reached out to me to talk shop over the phone one night.  I had a very enlightening conversation with Rod, who is an exceptionally gifted mechanical engineer with over 50 patents.  Rod also has his PhD and has worked on some exceptionally interesting projects – both on the job and for hobby.  He is an active home shop machinist as well.  Over the last few years Rod has done a significant amount of work in the 3D printing world – he is very active on Thingverse and also has did a significant amount of work on 3D printers themselves.

In the conversation Rod told me he had acquired all the hardware to put together a laser bandsaw prototype.  At first I thought he was making a joke, but he went into specifics about safety, power supplies and the actual laser itself.  Rod certainly had a workable design flushed out – one that both had us very excited.

In December Rod sent me an email that he had finished his laser bandsaw.  It could only really cut paper and balsa wood but to my knowledge it is the first working prototype of such a device.  Obviously a laser bandsaw is exceptionally hazardous – particularly to your eyes.  Rod pointed this out numerous times.  But with proper eye protection and proper design a device could be made to work.

Shortly afterward Rod posted his working prototype on Youtube:

So thanks to Rod the future is now here.  I’m watching with interest to see where this all goes.

$200 Shenzhen DRO (JCS900-2AE)

About 6 months ago I purchased a digital readout off eBay for the Rong-Fu mill drill. Originally I had planned to purchase either iGaging scales or standard import calipers and utilizing a tablet based DRO. Once I started looking at prices however I was shocked to find that for less than the price of either the iGaging scales or the import calipers I could have a full blown 2 axis DRO complete with proper glass scales.

I went ahead and ordered the scales off a eBay seller. It was a typical Chinese eBay seller that sells everything from DROs for machine tools to various useless cell phone and house gadgets. The total for the order was around $200 USD plus about $30 for shipping. I then communicated the scale lengths I needed via email. In about 2 days I had a shipping confirmation including a tracking number.

I was excepting to wait about 3-4 weeks for the shipment to arrive, typical of most stuff ordered from China. I was shocked at the end of the week when I received an email from DHL that my shipment was to arrive on the following Monday – about a week for the entire process! Sure enough Monday afternoon a DHL driver dropped off the 2 boxes.
The one box contained the DRO – a JingCE JCS900-2AE 2 axis DRO unit. The other box contained the 2 glass scales both of proper length. Also included was a large amount of hardware, mounting brackets and associated items you would need to install the DRO.

I spent the next few days thinking about how to mount the scales. The X axis was easy – I decided to mount it to the front of the table using the T slot already present. I thought about mounting it to the back of the table but I didn’t want to loose any Y axis travel. The Glass scales are rather bulky – something to note if you are considering installing them on a smaller mill like the X2 mini mill. The Y axis was a bit of a different story – there really isn’t anything to fasten the scales to. I decided to make up a bracket to hold the Y axis scale. That took a fair bit of work to do.

Y Axis Scale (behind the fabricated bracket)

X Axis Scale

After mounting the scales and trying out the DRO I also fitted a inexpensive import digital caliper to the quill to get a .001″ resolution readout for Z depth. This also took a few hours to do properly. 2 brackets were made out of aluminum to hold each end of the caliper. I modified the caliper using a Dremel tool. I drilled mounting holes using a standard off the shelf masonry drill bit – a poor man’s way of drilling hardened steel. High speed steel usually won’t touch hardened calipers.

Hard Drilling Using a Masonry Bit

After using the DRO for 6 months I can say that it is a very good unit. I haven’t had any issues. As far as accuracy and repeatability is considered, I really don’t have the proper measuring tools to qualify the DRO but I will say that I tested it using a dial indicator over the travel of the table. At each point where I tested the DRO it corresponded to the dial indicator – within at least .0005″ (as best as my judgment permits). I also ran the table up against a hard stop several times to test the repeatability and each reading was easily within .0005″. I probably should do a proper gauge R and R study on it, but just with the general testing I’ve done it’s easily within .001″. And to be honest doing work closer than .001″ on a Rong Fu mill drill is unreasonable.

I filmed and edited a number of videos showing the install and finally a video review of the DRO.  The first video shows the hard part: the installation of the Y axis scale.

The second video shows the installation of the X axis scale and also the mounting of a digital caliper on the quill.

The final video is me talking about the DRO itself and contains much of what is written here.

If you are interested in reading the manual, I scanned a copy of it and it is available here.

One thing to note is that you will get little to no support with the DRO. To me this isn’t a big deal at all when you consider the price. The next closest DRO in price in the North American market is approaching 4 times the cost. And the unit looks suspicious like this unit. If something breaks I am willing to try and fix the unit myself or simply replace it.
If I had a high end knee mill I would probably buy a Mitutoyo DRO and be done with it. But putting a Mitutoyo DRO on inexpensive import mills is a bit like putting lipstick on a pig.

It was a $200 well spent. Having a DRO on a milling machine is exceptionally handy. I won’t say it is a necessity, but it greatly improves your efficiency – especially on larger mills or making larger parts. Time will tell how durable the unit is but I think it is an excellent addition to a home metal shop.

Home Shop Machinists Podcast – Episode 15 – Snowed, Towed, and Tooled

If you are just starting out in your home shop or need a few ideas for your next project you will certainly find it in this episode.  After getting through the craft beer podcast and shop updates, which involve Max getting a tow, Max and Justin talk about useful simple shop tools as well as Tchotchkes and probably everything in between (don’t tell us you’re surprised!).  In the process both Max and Justin have extended their shop project lists.  You could even make a really nice homemade brake line flaring tool (we won’t talk about liability):

Some of the interesting links:

You can listen to it directly here:

or you can download it directly.

Subscribe in iTunes (and please rate us!): https://itunes.apple.com/podcast/home-shop-machinists-podcast/id1180854521

Max’s website: The Joy of Precision and also his Youtube channel:  https://www.youtube.com/channel/UCdMt_havo3BxZJscvRCOGcw Max’s Instagram: https://www.instagram.com/joyofprecision/

Justin’s Youtube channel: https://www.youtube.com/thecogwheel  Justin’s Instagram: https://www.instagram.com/thecogwheel/

Home Shop Machinists Podcast – Episode 14 – Phillipsed

When one Phillips isn’t enough.  Recorded in between years as Stefan would say, Max invites his brother Thayer and his father Fred on to join in an end of year discussion with our new semi regular co-host Stefan Gotteswinter!  In this episode we talk about:

  • Fred’s shop that Thayer works out of.  Fred has a really nice Rockwell mill (one of our all time home shop favourites) and a Southbend Heavy 13.
  • We talk about gunsmithing in the United States, Germany and Canada
  • Live free or die!
  • CAD and Stefan’s embrace of Autodesk Fusion.
  • Stefan machined some really nice Torx screws using his Deckel pantograph.
  • Justin is busy making Christmas presents.
  • Stefan wants to get a CNC lathe in 2018.
  • Max is hoping to finish his Trent pinion mill.
  • Both Max and Justin are hoping to get back to semi regular posting on Youtube.
  • And finally cars.  Max is hoping to get some German iron.

You can listen to it directly here:

or you can download it directly.

Subscribe in iTunes (and please rate us!): https://itunes.apple.com/podcast/home-shop-machinists-podcast/id1180854521

Many thanks to Fred and Thayer for joining in!

Many many thanks also to Stefan for coming back on and agreeing to become our third co-host!  We hope to get Stefan on much more frequently in 2018.  You can find his website here: http://gtwr.de/  Stefan also has one of the best machining Youtube channels: https://www.youtube.com/user/syyl.On Instagram: https://www.instagram.com/stefan_gtwr/

Max’s website: The Joy of Precision and also his Youtube channel:  https://www.youtube.com/channel/UCdMt_havo3BxZJscvRCOGcw Max’s Instagram: https://www.instagram.com/joyofprecision/

Justin’s Youtube channel: https://www.youtube.com/thecogwheel  Justin’s Instagram: https://www.instagram.com/thecogwheel/

A final note regarding the live stream with Robin Renzetti and Stefan Gotteswinter.  We are still hoping to do this in the next few weeks.  Stay tuned for more announcements!

Home Shop Machinists Podcast – Episode 13 – Have You Checked Your Oil?

After over a one month hiatus, Max and Justin are back with episode 13!

Some of the things we talk about include:

  • Max has had limited time in the shop.  What does work always get in the way of what we want to do?
  • Justin purchased a sub $200 USD digital read out from eBay.  He calls it the Shenzhen DRO.  And so far it has been pretty good.
  • Justin’s new lathe – a Standard Modern 12×30 Utilathe.  It was terribly dirty.
  • Which leads us into maintenance.  Why do so many people neglect equipment?
  • Max goes into the wonderfully simple cone style plain bearings.  Keep it clean and adjusted!
  • Bearing preload
  • How do you keep track of all those oil points?
  • The importance of way oil
  • Chuck lube.  Let the debate begin.  Max and Justin like getting sprayed with oil apparently.
  • A live stream episode with Stefan Gotteswinter and Robin Renzetti?  Let us know your thoughts!

All that and a few tangents (would it be a show without a few?)

You can listen to it directly here:

or you can download it directly.

Subscribe in iTunes (and please rate us!): https://itunes.apple.com/podcast/home-shop-machinists-podcast/id1180854521

Max’s website: The Joy of Precision and also his Youtube channel:  https://www.youtube.com/channel/UCdMt_havo3BxZJscvRCOGcw Max’s Instagram: https://www.instagram.com/joyofprecision/

Justin’s Youtube channel: https://www.youtube.com/thecogwheel  Justin’s Instagram: https://www.instagram.com/thecogwheel/