Lathe is running and track is set up!

[TexasTaxi]

I got a Grizzly Micro Lathe in, last week and finally un-boxed it this weekend. I played with it a bit, to true some wheels, but I think I could do a lot better with a different mandrel, other than the Derby Works (I think that's what I have). What kind of mandrel are all of you using on your lathes? I'm thinking about buying some extra pin gauges and turning some HDPE to make a wheel sandwich. I think a pin gauge that fit snug in the bore would give me much better results.

Then the 242 Best Track came in on Friday! I thought this thing was going to be a plug and play type thing, not an erector set! I did get it all put together, and the timer fitted and working, but I still need to file and sand all the joints. Konnor had a blast running his John Deere car and a ladder body that I threw together so he could have an actual race. He won his pack, with the John Deere car, and the ladder body that I threw together (with no underside skin), would beat his car every time. I know I'm learning, but still feel I have a long way to go. His car had a few runs under 3 seconds, but neither of those cars would do any better than 3.185 on our track.

A CNC router should be delivered sometime this week. I wonder how many cars we can build in the next 11 months!

 

[Darkside]

Lol! You sir are diving head first down the rabbit hole. Been there done that.

You're gonna find out really quickly that the DW mandrel is no good for cutting wheels. I think you are on track with the pin gauge wheel sandwich. That'll get you a lot closer.

I'm not sure what kind of chuck a grizzly comes with, but I'm going to assume that it's a 3-jaw. That'll work for machining from raw stock, but you'll find that a decent collet chuck is a must. That and a quick change tool post...

Forgive me if you know all this already. Just passing along a little of what I've learned from my dive down the rabbit hole.

 

[TexasTaxi]

I've done a lot of wood turning, but all new to "machinist" type stuff, so I'm still in a learning phase on this.

Yes, the Grizzly came with a 3 jaw chuck. It seems to be pretty easy, and accurate, from what I can see. What are the advantages of the collet chuck?

 

[Charles Studer]

If you are pin cutting make sure you zero run out that pin first

 

[Darkside]

I've done a lot of wood turning, but all new to "machinist" type stuff, so I'm still in a learning phase on this.

Yes, the Grizzly came with a 3 jaw chuck. It seems to be pretty easy, and accurate, from what I can see. What are the advantages of the collet chuck?

Repeatability... A 3-jaw is great for initial machining, but dialing the runout to zero of a precision part like an axle or a pin gauge is extremely difficult if not impossible with a 3-jaw. They are really meant for mounting and machining raw stock.

And just to clarify. I'm no pro machinist. Everything I learned about machining I learned by machining. It's just that I've been down the road you just turned on to. So just passing along what I've learned.

 

[TRE]

I cut my wheels with 3 jaw chuck and pin guage..it csn be done

 

[Racing358t]

IMO, for best results with a 3 jaw a person needs to chuck up on a piece of larger diameter than needed carbon steel stock then machine their own pin out of it. Once machined it will be as good as the tolerances of the lathe.

If using a collett a person can get the best results by machining their own pin also. The nice thing about a collett system is that a it is easier for a person to leave the pin in the collett assembly as a pair and then it's always good even if they change to different attachment. The same thing is true for 3 jaw. If a person has multiple 3 jaw attachments they can leave the pin in the 3 jaw as a pair and change to different 3 jaws when working on other items.

I have been able to chuck up on a pin gauge with the 3 jaw and get near zero run-out. But it is a crapshoot and tedious to keep chucking and re-chucking in a effort to find the magic spot. With the colletts there is a higher chance of getting to the zero run-out position when trying to use pin gauges as the "pin"

Scott

 

[TexasTaxi]

CNC Router was delivered yesterday!

Time to get to work!

 

[TexasTaxi]

After a few computer problems (my work laptop was running an unsupported Windows version), I got the router up and running, and cut 4 cars. The first was destroyed when I tried to cut it to thickness on a poorly tuned and dull band saw. The second car was a modified "stick dragster", that I threw some weight into, pulled some prepped wheels off of another car, with some bought axles ... raw wood; it ran 3.11 on my 42 foot Best Track. Konnor's car, that won our Pack derby, ran a 3.18 on my track, for comparison.

I cut another square ladder body that weighed 10 grams, and an triangular shaped ladder body that weighed 7 grams! These both have the top "skin" left on them ... not cut all the way through. You can hold it up to the light, and they're barely translucent.

I know you guys have already said that a thin wedge is the fastest, but I like playing, and to some extent I have to prove it to myself, which will be the fastest.

The 3.11 car did have quite a bit of wiggle, going down the track. I assume it's an alignment issue.