Spider for my G0602/0752Z 10 x 22

[verbotenwhisky]

What are the specific words or descriptions for getting the correct "version" of 4140? Not familiar with the terminology. Pre hardened 4140 HT? Buying from McMaster is pricey, so I get forced (not really, but there's budget pressure) into looking on eBay and places like that. Lots of creative words used so don't want to buy the wrong item.

The prehardened has a light heat treat but is still machinable and when I buy it, it is designated as 4140-HT. It can still be treated further but works great as is for most of what I do.

 

[WobblyHand]

Made some progress this morning. Did a quick double check and discovered that I had bored the section for threads to match the male thread spec, not the internal thread spec. Fortunately that was recoverable and I continued to bore it out and got within a thousandth of nominal.

Making the groove was dicey. This 4340 has not so good machinability and the tool dove in a few times creating huge burs and stalling the lathe. Once the thread form was in full distance it was ok to enlarge the groove since it was only cutting on one edge. Threading in reverse went ok, except for a noticeable loosening of something in the lathe. It seemed that the cross slide was being pulled into the cut as I saw the dro change. Something has loosened up, I'll have to hunt it down, might be the gibs need adjustment. But got through it with a part that screws on the lathe (the first time) which is better than the spider on my mini-lathe.



This afternoon will be on the mill.

 

[WobblyHand]

Not as pretty as I'd like, but still ok. Need to de-bur the slots. Haven't figured out how to drill 4 holes with 3 jaws in the way. Maybe I will draw or sketch something to see if there's clearance without removing the piece from the chuck. Worst case I flip the piece, but I'd rather keep it in the chuck. I need to fit 4 M6 screws at right angles at 32mm from the front face (really 10mm from the face of the chuck). Guess I'll model the chuck jaws and play with rotating the hole pattern around. On the chuck, and rotating the piece, I didn't see how to fit it in.
-

 

[WobblyHand]

Pretty much convinced myself that there's no way to drill the other holes without hitting a jaw. Made a sketch of the jaws, or rather holes where the jaws would be, and rotating the jaws about - just not going to work with the chuck I have and its 16mm wide jaws. So I will have to flip the piece and put the slots (in the previous picture) against the chuck face. If I had a four jaw for this dividing head, it would have been easy (save for centering it).

Next chance I have to work on this might be Sunday. I'll have to flip the work piece and drill the holes and tap them. This 4340 will be hard to tap, at least based on its machinability.

 

[WobblyHand]

Well got this part done. Think the screw holes came out better than on the mini-spider, so that's an improvement. I had to flip the work piece, so there's some fixed but not exact angle from the notches. Won't matter. The mill scale on the exterior sort of bugs me. Didn't think it would, but now that it's machined, it looks unfinished. Should have made a mandrel when there only was a 26mm hole through it. If I had a bull nose live center maybe I could just do it between centers. But I don't have one. Hey, I can use the male threaded piece I made as a spindle thread model! Won't be perfect but it will hold this piece so I can turn off the crud.

Next steps, turn the OD and make some more brass tipped screws. I didn't document (show any pictures) making the screws, so that might be good to do.

 

[WobblyHand]

That's a little nicer than the mill scale finish!

One minor problem, the spanner wrench that I used for the mini-lathe spider doesn't fit on this due to the increased diameter. the pin is off angle and won't fit in the slot. I can tap it into place, but it would be nice to have a spanner that fits correctly. A different day's project.

Brass tipped screws for tomorrow.

 

[verbotenwhisky]

Well got this part done. Think the screw holes came out better than on the mini-spider, so that's an improvement. I had to flip the work piece, so there's some fixed but not exact angle from the notches. Won't matter. The mill scale on the exterior sort of bugs me. Didn't think it would, but now that it's machined, it looks unfinished. Should have made a mandrel when there only was a 26mm hole through it. If I had a bull nose live center maybe I could just do it between centers. But I don't have one. Hey, I can use the male threaded piece I made as a spindle thread model! Won't be perfect but it will hold this piece so I can turn off the crud.
View attachment 497554View attachment 497555
Next steps, turn the OD and make some more brass tipped screws. I didn't document (show any pictures) making the screws, so that might be good to do.

Take a zip lock bag and put white vinegar in it then put the part in it submerged and leave it over night, the next morning the mill scale will wipe off like dirt.

 

[WobblyHand]

Take a zip lock bag and put white vinegar in it then put the part in it submerged and leave it over night, the next morning the mill scale will wipe off like dirt.

Good to know. I'll try that next time.

I turned the OD anyways since it was kind of rough. Will put it in the ultrasonic cleaner inside a small jar filled with isopropyl alcohol to get out all the machining residue. That works well and doesn't promote rust. I've cleaned before in hot water and detergent and got flash rust after I pulled the item out of the tank. It was unbelievably fast turning to orange.

But, I may rust it anyways, since I was thinking of cold blueing it. This isn't a fine firearm so a minor blemish in the blue finish won't matter. The cold bluing process consists of promoting rust, carding it and boiling it in water to convert the rust to magnetite which is dark blue/black. I use hydrogen peroxide and salt to get it to rust. Worked ok the time I tried it, it was relatively cheap to do and no super toxic stuff was needed. Takes patience and quite a few iterations, but it does work.

 

[verbotenwhisky]

Good to know. I'll try that next time.

I turned the OD anyways since it was kind of rough. Will put it in the ultrasonic cleaner inside a small jar filled with isopropyl alcohol to get out all the machining residue. That works well and doesn't promote rust. I've cleaned before in hot water and detergent and got flash rust after I pulled the item out of the tank. It was unbelievably fast turning to orange.

But, I may rust it anyways, since I was thinking of cold blueing it. This isn't a fine firearm so a minor blemish in the blue finish won't matter. The cold bluing process consists of promoting rust, carding it and boiling it in water to convert the rust to magnetite which is dark blue/black. I use hydrogen peroxide and salt to get it to rust. Worked ok the time I tried it, it was relatively cheap to do and no super toxic stuff was needed. Takes patience and quite a few iterations, but it does work.

Yes, I use cold blueing as well. I hate mill scale and the vinegar is the easiest way I have found to deal with it and get clean metal, once out of the vinegar I usually coat the metal with WD40 to prevent rust while working on it.

 

[WobblyHand]

Haven't gotten to the brass tipped screws on this yet. Found out that my ER32 hook spanner wrench won't quite work on this, so I need to come up with a 57mm diameter wrench. Yeah, I could buy some wrench from the far east and modify it, but I just decided to design one - to get an idea of what I needed. It's not very good looking at this point, but I was checking for fit. I printed it to see if the basic idea worked, and it does with a few minor changes of hook length. I'm glad I did print it, as the handle needs to be a little longer. I only made a 6" handle and it really should be around 9" minimum, just to get my hands away from the gears and pulleys.

I looked into Sendcutsend and found out that they have a minimum order of $29. Since I'll make a pair of wrenches, I suppose that is not too bad. The quote was $8.34 for two wrenches in mild steel, with a padding to $29.00. Think I'll refine my design first before doing anything. More beefing up and smoothing out some of the sharp shapes. The artsy aesthetic stuff, which I admittedly am no so good at. Increasing the length, widening the handle and adding smoothed curves will undoubtedly increase the price. As will powder coating.