Tips/Techniques Dan Gelbart shows how to test lathes and mills

Dan Gelbart in his bat cave discusses how to test lathes and mills. Of course his equipment is amazing (and pricey!). CNC gear but with manual handles for all the axis. I almost hate to try these tests on my machines. Performing these tests while inspecting a potential purchase could be quite helpful. Maybe I'll try a few of those tests and post results - be interesting to see results from other members.

He also explains the advantages of the 3D metal printer he designed. Maybe the forum could buy one! just $200K. Really good content from Dan as usual.

EDIT dec 2023-> Dan has deleted this video as he was not happy with it. You can read the thread still and get a feel for most of the testing from the video.

 

[Dabbler]

@TorontoBuilder The C0636 is actually a serious lathe. No *quite* as sturdy as a Colchester Toolroom. It weighs in at 1745 lbs, (ask me how I know) and has an abundance of both metric and imperial screw pitches.

For an under-2000lb lathe is is very rigid and capable.

Having evaluated a Colchester Student recently, I'd say it is just as rigid, but far more versatile. It can take a .100DOC (.200 off diameter) with a sharp tool. It has a 1ph 3HP motor, and a good selection of speeds.

Thus ends the advertisement

 

[garball]

That must have been a pretty clapped out Colchester lol.

 

[Dabbler]

That must have been a pretty clapped out Colchester lol.

Very good shape. well used, but not abused.

The 636 is a capable lathe, made to very good standards. Not all Chines stuff is junk. Modern ensures good quality control, and they pay for quality, and that's why they are more money than the usual.

They aren't a Monarch 10ee or a Colchester Toolmaster by any means, but a high-quality hobby or entry level commercial lathe.

 

[Janger]

@Janger and I will be comparing a Noga and his Insize side-by-side. I'm hoping that the results will be useful to everyone wanting to buy one or the other.

Noga vs insize magnetic base compared! Side by side you can see the noga is better. The magnet is stronger. The arm bars are thicker and there is less wiggle when pressing on the arms. The noga ‘feels’ a little smoother and the fine adjust is noticeably’finer’. For $100-150 less though the insize is still really nice and a great buy. I don’t regret getting it over the noga. Dabbler and I think it’s about 65% of the noga overall.

 

[Dabbler]

My view is that the insize is quite adequate. The magnet is *just* strong enough, the holding on the arm is okay, and the adjustment is one you can 'get by with' A good value, but not the same as the Noga. If i needed a secondary stand, I'd consider the insize based on cost.

 

[Dabbler]

John N and I checked out his lathe today. With a 2" bar chucked in his 3 jaw chuch and John putting his weight on it, we got .001 movement 18" from the headstock, and 1/3 of a thou near the headstock.

When we turned the 2" piece down, we got about a quarter thou if vibration on the indicator, but no bias towards out of round.

 

[hunter1991]

Dan Gelbart in his bat cave discusses how to test lathes and mills. Of course his equipment is amazing (and pricey!). CNC gear but with manual handles for all the axis. I almost hate to try these tests on my machines. Performing these tests while inspecting a potential purchase could be quite helpful. Maybe I'll try a few of those tests and post results - be interesting to see results from other members.

He also explains the advantages of the 3D metal printer he designed. Maybe the forum could buy one! just $200K. Really good content from Dan as usual.

What happened to this video? I can't find it anywhere. I watched part of it, then said I would come back and watch it later. But it has vanished! This forum is the only reason I know I wasn't imagining it

 

[gerritv]

Because Dan decided to mark the video as private. You could try to contact him via YT

 

[Susquatch]

What happened to this video? I can't find it anywhere. I watched part of it, then said I would come back and watch it later. But it has vanished! This forum is the only reason I know I wasn't imagining it

It looks to me like Gelbert or his assistants marked it private. Unless you have a personal connection with him, I think you are SOL.....

Prolly enough of the members watched it to be able to give you highlights Are you just wanting to pick up where you left off or after something in particular?

 

[hunter1991]

Haha, thanks for at least helping me know I wasn't crazy. Can someone summarize the tests he did in the video? My understanding from this forum:

1. Mount indicator on headstock, apply force to spindle and measure deflection
(I think he used the spring to do this? Putting the spring between the toolholder and the spindle and applying force with the cross-slide)
2. Something similar with a milling machine, maybe mounting indicator on the table and applying a force, measuring spindle-table deflection.

Thanks,
-Hunter

 

[hunter1991]

I have a small lathe and a small mill, and a large lathe and large mill and I thought it would be interesting to compare the rigidity of each.

-Hunter

 

[Susquatch]

Can someone summarize the tests he did in the video? My understanding from this forum:

I'd welcome differences of opinion, but personally, my impression was that he was evaluating how good a really good lathe was. Certainly not giving advice on how to check how bad it is. More of a reality check for those who believe their machine is perfect.

His tests were more about checking the flex in an already very rigid tool room type machine. Most machines would probably do poorly but that wouldn't make them bad machines.

 

[Janger]

Haha, thanks for at least helping me know I wasn't crazy. Can someone summarize the tests he did in the video? My understanding from this forum:

1. Mount indicator on headstock, apply force to spindle and measure deflection
(I think he used the spring to do this? Putting the spring between the toolholder and the spindle and applying force with the cross-slide)
2. Something similar with a milling machine, maybe mounting indicator on the table and applying a force, measuring spindle-table deflection.

Thanks,
-Hunter

Another test was to turn down a bar carefully and then measure the concentricity of the turned section with a DTI - or the best measurement tool you have. Measure by putting the DTI on the turned down section and spin the chuck. Dan had a very sensitive interrapid Mahr 1 micron indicator (~$1000). The resulting measurement shows the condition and quality of the head stock bearings. On a theoretically "perfect" lathe there would be no irregularities and nothing to measure.

Dan did make a spring - but as you can see above I just pushed hard!

 

[Ironman]

I love the photo of you trying to push over your lathe. Somehow or another my brain translated that into you trying to push a cow sideways in her stall so you could get your milk bucket under her........

Ya, watch out that Bessy doesn't kick that bucket of yours.......

John, maybe a review of a video on Cow Tipping would be beneficial.

 

[Janger]

John, maybe a review of a video on Cow Tipping would be beneficial.

I can't wait to see this! Susquatch let's go! Do you have any cows?

 

[Janger]

ah watching the Pixar Cars movie with the kids...Tractor tipping! Good memories.

 

[Susquatch]

I can't wait to see this! Susquatch let's go! Do you have any cows?

Nope. We did in Saskatchewan, but I didn't want anything here that produced crap as it grows. No domestic animals on my farm.

We could try tipping deer....

 

[slow-poke]

I sure would like to watch this video. I realize this thread is older but when I click on the video link I get a private video message. Does anyone know if the video is still available?

 

[Janger]

I sure would like to watch this video. I realize this thread is older but when I click on the video link I get a private video message. Does anyone know if the video is still available?

I can't find it either. So I posted on Dan's company's web page asking about the video. Rapida.com. Let's see what happens.

 

[Dabbler]

A while ago I found a guy on an obscure forum that had the video and mailed it to another member. I wasn't a member of that forum, so I let it be. I kind of wish I had joined just to get that video. My understanding is that Dan deleted the old video.