Craftsman/Atlas 618 lathe - compound rest crack
ฝัง
- เผยแพร่เมื่อ 22 เม.ย. 2024
- After watching the Mrpete222 video on the atlas compound rest ( • SHOP TIPS #232 The Com... ), since mine was not locking completely I decided to take it off and have a look at it to see if I could figure out what was happening. I also noticed that my new quick change tool post has a conflict in the corner against the compound rest, and so I decided to see if I could grind out a bit off there to make it swivel around better.
After coming in from the garage I researched the compound a bit more and found that the originals were made of cast iron. That is why it shows the tool marks for the grinding etc that I noticed in the video. However, as I was taking it off, I noticed the crack on the one end in the cast iron t-slot. It is not cracked far enough to fall off (yet) but that is not ideal...so I need to figure out what I want to do next, ie do I try and get it ground out and brazed, or buy a new solid steel one (I did see people selling those), or use it until it breaks and possibly also ruins the part I am working on at the time. MrPete222 also has a set of videos on how to make your own from steel, but he used a bridgeport...which I do not have. Granted, this lathe has the milling attachment, but I doubt it would be time effective to try and make that in steel with it, assuming it could even handle a part that big. ie taking those cuts at a thousandth at a time...would take a WHILE.
Suggestions are welcome in the comments for what you have done or would do in a similar situation. - แนวปฏิบัติและการใช้ชีวิต
Instead of grinding away part of your cross slide to make clearance for the QCTP, just make a big washer to raise it up a bit.
I thought about that, but if I raise that it could impact where the tools hit the center line of the material...ie from what I watched/read you want the tool cut to be right at the center line not above it. I also got feedback after the video to just nick the corner off the tool post and that may be easier/less work.
I was about to comment and say just turn out a spacer for the QCTP !
@@JohnDoe-qg6hm Yeah the only thing I am not sure with raising it up further is if that will impact the centerline and the tool position. I think I am correct that I saw on other yourube videos etc that you want to be cutting at the centerline. If that is wrong I am hopeful that someone will correct my understanding of it. :)
That cracked part is cast iron. If you can manage to drill a small hole from the outside into the end of the crack, that will help to stop the crack from spreading. Short of brazing the crack and re-cutting the dovetail, you might try drilling and tapping for a small machine screw to hold the crack closed.
Thanks, that is a useful suggestion. since the video the list of possible options has grown:
- clean it out and silver solder it after getting it all uniformly hot to help prevent cracks (and then protect it as it slow cools)
- clean it out and braze/weld/tig weld it after getting it all uniformly hot to help prevent cracks (and then protect it as it slow cools)
- drill and tap/put a bolt down in it to hold it together (that would be a challenge due to the small amount of material in the actual corner that is not also impacted by the dovetail right below it)
- make a new one using someones milling machine such as the four MrPete222 videos that he did where he did just that, but he used a bridgeport milling machine to do most of the milling work
- buy a fully made all steel one that someone else made
- wait until it fully cracks as under normal light cut hobby use it may last for years just like it is now, then do one of the above ideas.
Yea a bit of brazing and some filing will sort out the crack no doubt but if your no use at brazing perhaps ask a shop to do it ! It can be difficult if the metal is not clean and as the cracked part is not separated you cant clean it very well !
@@JohnDoe-qg6hm My other option is to buy a steel replacement that I saw someone selling as a drop in replacement. It is good to know that is an option if my fix fails, or it finally breaks entirely.
That compound is known for breaking in half. That's why there are reproductions available that cost more than an Atlas lathe is worth.
Well I got this one fairly cheap...so even with the extras I have bought since then it is still less than what I have seen standalone units sell for. And I did buy one of the all steel replacements and that should solve my issues.
29 1/2 degrees for threading. If it was me I would use it and see how it affects your work. For hobby work you may not have to do anything to it.
Thanks, I think I will see how things go for what i choose to do with it. I may just get the steel replacement someone is selling and then it would be "done" :)
Part it out and never buy another Atlas lathe. Even Chinese is better.
I have heard it the other way too. This one at least does not have the plastic gears etc that the chinese ones do....granted the gears in this are that softer metal, but still, are metal not plastic. For now I will try this one and learn on it and have some fun. I have a supposedly "exact match drop in replacement all steel compound" on order from ebay that will be here in a week or so, that should solve this issue and prevent it from happening again, and hopefully will also solve the binding up issue for the quick change tool post that I was having, as the new one is a straight flat top vs the curves. If it totally pisses me off, this is still a popular lathe and I should be able to get my money back when I re-sell it since it has the complete accessories kit that goes with it.