best material for making a quill

[Mcgyver]

I'm with Doozer on whether its worth it, but here a few points on redoing quills and bores

1) if the quill is badly worn, so to will be the bore....little point in dealing with half the problem
2) if you look at commercial laps, yes they are longer than the bore, but they also have a very tricky to machine small long tapered bores and mandrels.....its how they are set/expanded. That would be an adventure to try and make...I'd buy one but bet they are not cheap
3) the DIY internal lap, some of mine shown below do not produce a bell mouth with careful use. (as measure with 10ths Mit dial bore gauges) with fine compound you can feel a tenths difference as you are lapping so you concentrate on the tight spots
4) Consider getting the bore to someone with a Sunnen, I've got one and it is quite easy to produce bores to 10th, straight and round. I've got one, an amazing machine...err contraption
5) its a bunch of work to make a quill - you need the internal taper as well
6) if you get the old quill hard chromed, you usually grind it first, gives the chrome something to adhere
7) you can have areas masked off if necessary, i.e. internal bore, flat for the rack etc
8) do the bore first, then grind the quill to suit - best practices iirc is to strive for 3/10ths clearance
9) cost can factor into it, I can get stuff hard chromed cheaply then grind it myself....I've also heard of people getting quotes of $800 for hard chroming and grinding a quill.
10) you can also easily make an external lap if you are making a quill
11) sandpaper on a stick isn't lapping (maybe polishing?) as there is no control....with a lap you can and control where material is removed
12) As for your original question, a chrome moly pre-hardened would be the best choice for a new quill imo. 1144 also works, just not quite as tough (but easier to machine)
13) Whatever way you go, lapping it for the final finish would, I think, make it longer lasting....lapping will give a finer finish than grinding (depending on your grinder than may matter less or more)
14) no need for the (supposedly) none embedding compound. That's used for creating a bit of slop between parts. When using a lap, just used regular lapping compound (e.g. Clover). The lap is always softer than then work so the compound embeds in the lap. its actually a bit embedding and roiling, the lap does get worn away from the rolling (unlike a charged flap, say) which is good; it corrects the shape of the lap

[nickel-city-fab]

If you can find an automotive machine shop with a
Sunnen hone, that would be the way to go.
Probably cost between 50 and 100.
Those hones are used for the cylinders and connecting rods.
Ask around.
Guaranteed you would have to make a new quill to very tight tolerances --
-- I wonder if a heavy chunk of TGP rod
--or even an old hydraulic rod would work.
If you could get the bore honed out to fit one of those.

[Barefoot]

I'll put this here for future reference:
MAKING AND USING LARGE DIAMETER LAPS - YouTube

[Barefoot]

I'm with Doozer on whether its worth it...

I'm with Doozer as well, but it's what I'm stuck with for now.



I'll report back after I can get it torn down and mic everything.

Thanks for everyone's input. Really appreciate it.

[Paul Alciatore]

I may be way off here, but wouldn't it be a good idea to bore it first to get it straight and round and then worry about lapping?

[nickel-city-fab]

I may be way off here, but wouldn't it be a good idea to bore it first to get it straight and round and then worry about lapping?

Yep -- that's why I initially suggested making an aluminum lap that is 2x longer than the bore. Also to avoid bell-mouthing issues.

[dian]

to use moglice (or make your own) you have to grind the quill first.

[old mart]

If the bore is bellmouthed even 0.003" at the lower end, it would take a huge ammount of lapping.
If a lathe with enough swing can be found, I would set up a steel bar in a four jaw chuck with about 4" sticking out and turn the end 2 1/2" so the mill head just fits on it from the top half of the quill bore. Then bore the lower part to just clean up the bore. Turn the bar around in the chuck and turn it to just accept the mill head the other way round and bore to match the first end. Holding about 2 1/2" would support about 1/3 of the length assuming the quill moves 3" and would be good enough.

[psomero]

Actually the moglice is a great suggestion from TMB. It is almost certainly the cheapest and easiest way to do the job. Using the proper release agent, you can use your existing quill to mold it. Make the quill very shiny first, and remove the rack if possible.

Just make sure the quill itself ain't a tapered cone first. Molding off of an angle will get you an angle and not solve the slop problem at extension.



Don't expect to take more than a couple tenths off with a lap. You should bore the hole over its current maximum diameter and round, then make it really round and true with the lap.

Either way, you have to map out and true up the geometry on one of the parts first.

[psomero]

TACrafted, some German guy, did a quill sleeve on a RF45 clone. NYCCNC had a shop tour that had shown it off. I assume he has more videos on his own channel, but never seen them. https://youtu.be/In6VqiHL7rM?t=1279

I am mildly interested in doing things to my own G0759 quill because it's a definite weak link on an otherwise decent machine. Haven't bothered to check and adjust the gibs on the column, or actually check the condition/preload on the spindle bearings, so need to do some stuff first. I also just picked up a Biax 7ELM, sooo...

[Mcgyver]

Has anyone here actually used moglice or heard of it use for a 'trapped' (vs one mating part sitting on another like a lathe carriage) application like this? You have to have some clearance or the parts won't move.....where does the clearance come from?

If there's an easy way out of that issue (there maybe, I hardly know everything about moglice applications), you're also going need to get one part machined with a ground or lapped finish and perfect geometry such that you can have a thick enough layer of moglice to work. Lastly, these resin type fills are suppose have fancy rubber fit seals made and installed as any chips or debris that gets in there will likely embed in the plastic and grind away at the mating part. They are a very cost effective way to recondition a machine tool bearing set up...no doubt....but I'm not convinced they are the best.

[nickel-city-fab]

So.... whats stopping anyone from using moglice? Of course you have to polish up the mating shaft. Or just use some TGP rod. Or an old hydraulic rod. YES you are supposed to use the release agent -- else you won't get the part out. The release agent also gives a very small clearance, I would imagine sub-micron.

[The Metal Butcher]

Hydraulic rod is very round, straight (when new) and chromed, yet still soft enough on the inside to be machined. Assuming the diameter was right, that would be the way to go. And since it's sold in standard lengths, the odds of a hydro shop having a short drop they would give you or sell for scrap price is pretty good. I've got to agree with Nickel here.

[J Tiers]

So.... whats stopping anyone from using moglice? Of course you have to polish up the mating shaft. Or just use some TGP rod. Or an old hydraulic rod. YES you are supposed to use the release agent -- else you won't get the part out. The release agent also gives a very small clearance, I would imagine sub-micron.

Moglice would likely work well on a tailstock barrel. Those usually have a long contact length inside the barrel, and near-100% contact, other than the key slot area (which would need to be dealt with).

The "small bench mills", aka "mill-drills" may have drill-press type construction, meaning they have 2 , or in some cases, three, ring contact areas, but nothing remotely approaching 100% coverage. Such design would not be very suitable for Moglice, it would be far better to use some form of sleeve arrangement.

My 18" Atlas-Clausing drill press has that sort of support, three rings, each of the upper ones maybe a half inch wide at most. It's not a consumer item, but an industrial version with an MT3 spindle. I do not know how moglice would work well on that, it seems to depend on a fairly large area and low force per unit area. If I ever do any work on the quill area, I would sleeve it, but never consider Moglice, at least as I understand that material at the moment..

[The Metal Butcher]

Moglice would likely work well on a tailstock barrel. Those usually have a long contact length inside the barrel, and near-100% contact, other than the key slot area (which would need to be dealt with).

The "small bench mills", aka "mill-drills" may have drill-press type construction, meaning they have 2 , or in some cases, three, ring contact areas, but nothing remotely approaching 100% coverage. Such design would not be very suitable for Moglice, it would be far better to use some form of sleeve arrangement.

My 18" Atlas-Clausing drill press has that sort of support, three rings, each of the upper ones maybe a half inch wide at most. It's not a consumer item, but an industrial version with an MT3 spindle. I do not know how moglice would work well on that, it seems to depend on a fairly large area and low force per unit area. If I ever do any work on the quill area, I would sleeve it, but never consider Moglice, at least as I understand that material at the moment..

Why couldn't the areas in between be filled with moglice as well to make complete contact?