Setting-up the PM 1236-T Lathe

[SteveStash]

Yep, the hand wheel was very familiar to me. I grew up playing on a Clausing identical to the one in the attachment. I am looking to purchase the 1236t in 1PH. How do you like yours after using it for a few years now?

 

[Ken226]

So the outer spindle diameter is the same? Wonder why they didn't just use the same spindle...

The best I can do on that question is to guess.


Grizzly told the factory in China they want a d1-5 spindle and 1.57 bore. The factory did what was most economical, adjusted the camlock to d1-5 dimensions and bored the inside bigger.

That's just a wild guess.

 

[Titanium Knurler]

Yep, the hand wheel was very familiar to me. I grew up playing on a Clausing identical to the one in the attachment. I am looking to purchase the 1236t in 1PH. How do you like yours after using it for a few years now?

Hi Steve, the lathe has not disappointed me. It has been exceptionally reliable and accurate but take this with a grain of salt since I am a newbie and this is my first and likely my last lathe. What has been interesting to me is that I use it much more than I thought I would. I don’t know how I got along without a lathe and milling machine.

My only complaint is that PM uses a very poor quality belt. I would have a replacement ready for when the stock belt fails or just replace it right away before your lathe is covered with black belt dust.

The only other point is that I would consider 3PH power if it is an option for you.

Please feel free to ask me anything you like about the lathe, I am happy to help if I can.

Mike

 

[Titanium Knurler]

I realize I'm responding to something you mentioned in 2019, but I had a mostly useless, academic thought I wanted to run by you

When I read this part of your post, I wondered just how much more rigid would the d1-5 in the g4003g be than a d1-4 in a similar class of machine.

So, the point on the spindle that would be subject to the most deflection stress should be the main spindle bearing behind the spindle, right?

I looked up the specs on 2 similar machines, with each respective spindle. The g4003g and the g4003.

The G4003g has a d1-5 spindle with a 1.57" spindle bore and, according to manual uses a 30212 (60mm Id, or 2.3622" ) bearing. That would make the spindles wall thickness @ the main bearing 0.3961"

The G4003 has a d1-4 spindle, and according to the manual has a 1.417" spindle bore. It also uses the 30212 bearing. That would make the spindle wall thickness @ the main bearing .4725".

So, regardless of the d1-5 spindle mount, the g4003g spindles OD @ the bearing boss is the same as that of the g4003 @ 60mm ( 2.3622"). But the 4003g has a significantly larger bore, and correspondingly less spindle wall thickness.

Taking that into consideration, I wonder just how much more rigid is the g4003g spindle? May even be less rigid, perhaps?

A purely academic thought, since I own neither machine.

Ken226, your reasoning makes sense to me. If I understand your description correctly, in this instance, the D1-5 spindle has the same OD and bearing as the D1-4 spindle but a thinner spindle wall because the spindle bore is minimally larger. I am not an engineer but I think it would be difficult to make a case for the D1-5 spindle being more rigid with it’s thinner wall. Also, I am not sure whether these two examples are representative of D1-4 and D1-5 spindles from other manufacturers and one has to wonder if, in this case, the manufacturer chose a similar part and simply enlarged the bore a bit since the consumer expects a larger spindle bore with a D1-5 machine.

Now we have combined your “purely academic thought” with my pure conjecture and am afraid we may be entering into the realm of BS : ) but I have a feeling that most likely mksj and Mikey are correct that with machines this size the D1-4 vs D1-5 spindle probably doesn’t make much difference.

 

[Ken226]

Also, I am not sure whether these two examples are representative of D1-4 and D1-5 spindles from other manufacturers and one has to wonder if, in this case, the manufacturer chose a similar part and simply enlarged the bore a bit since the consumer expects a larger spindle bore with a D1-5 machine.

Just to see, I looked up Grizzlys biggest lathe equipped with a d1-5 spindle (that I spotted with a quick look). The G0824 is their 14x40 gunsmith lathe. It has a a d1-5 spindle, a 2" spindle bore and uses a 32015 bearing.

The 32015 bearing has an inner race ID of 75mm. That puts the wall thickness @ .4765"

So, I guess the G4003g spindle is definitely not representative of all d1-5 spindles.

My Birmingham 13x40 is a d1-4. It's spindle specs are near identical to the Standard g4003. It has a 1.437" bore, uses the same 30212 bearing, So it has a wall thickness of .4625".

Now, I have little doubt that the G4003G spindle is plenty strong enough. But I doubt it had a rigidity advantage over similar size D1-4 spindles.

The G0824 d1-5 spindle however, is definitely, without a doubt more rigid.

 

[szenieh]

It is difficult for me to understand why you keep calling yourself a "newbie"! The level of understanding, analysis of the issues and the synthesis of the solution indicate a great deal of depth and experience. Not knowing what your background is, I would say that you had a great deal of mechanical design hands-on experience and a serious engineering education.

I am learning a great deal from this thread. Thank you for sharing.

Salah

 

[Titanium Knurler]

Salah, I am very pleased that you have found this thread useful and appreciate your kind words. I apologize for not responding sooner but an impromptu road trip to Utah and COVID intervened.

I feel this thread is unfinished and hope to add to it in the future now that I have many hours in front of the machine.

Regards,
TK

 

[Just for fun]

TK, You have did an exceptional job putting your lathe together, it looks great!

Your documentation in this thread is also exceptional.

Thank You for all your efforts!

Tim

 

[Downunder Bob]

Jester966, think of it this way. Say you are a machinist on a battle ship, your captain runs aground in choppy seas and bends the prop shaft. The enemy is approaching and you need to turn a new prop shaft pronto! Your lathe was adjusted on land to have no twist in the ways and then bolted to the battle ship. But now you are at sea, the ship is pitching and rolling! What do you do? You turn a perfectly untapered shaft because the movement of the ship, even though it is creating a constantly unlevel lathe, has no affect on your lathe as long as the ways are untwisted. You are promoted, retire with a huge pension and live happily ever after. Think of the plate on the mobile base as the battle ship.

Absolutely correct, I spent a large part of my working life as an engineer on cargo ships. Most of those ships had a workshop that included a lathe, some also had other machines such as mills, one even had a shaper.
These machines were always bolted to a very stiff sub base which was welded to the ships frame. This was done in such a way that the machine could be set up square to itself, they would almost never be level, but within themself would always be square.
Machining to tight tolerances was never a problem.

 

[Titanium Knurler]

TK, You have did an exceptional job putting your lathe together, it looks great!

Your documentation in this thread is also exceptional.

Thank You for all your efforts!

Tim

Thanks you and I appreciate your feedback!