Machining a Model Steam Engine - Part 9 - Eccentric Hub

[@alcostich9317]

Joe, Have enjoyed this series and look forward to the next instalment. Any chance you would consider creating a video on machining one of PMR's model machines...perhaps the lathe or shaper or horizontal mill? I have one of each of these for years but lack the confidence and skills to start one. Thanks.

[@joepie221]

There is a very good chance, the next model I decide to build will be their lathe model. I'll pin this comment and lets see how many thumbs up that idea gets.

[@joell439]

@@joepie221 - As you know, we all learn something from you on every episode. If you have the time to video and share, I'll be watching and learning. Joel...... 👍👍😎👍👍

[@radbot1]

@@joepie221 I didn't know there even was such a thing. That would be awesome!

[@eligatlin144]

I know Im randomly asking but does someone know of a method to get back into an instagram account..? I stupidly forgot the password. I would appreciate any help you can offer me!

[@benjaminjustice2438]

@Eli Gatlin instablaster :)

[@AndrewArndts]

The more I watch all of you machinists, the better my wood turning becomes.

[@evilbrat5376]

You lost me on the math but really what marvels me is the operation of machining the parts for this steam engine by you. You hooked me.

[@wwilcox2726]

The math was to calculate the values when using the digital read out "DRO". If you keep that in mind and watch that sequence one more time it will have more relevance for you. Don't give up on it. I got a little lost in the middle myself, but I got it just as he was done with his work sheet. Cheers!

[@jerseyjoe2684]

Another great video, Joe. Always happy to see another old timer like myself passing on the tricks of the trade. Watching your videos is kind of a "bus man's holiday" for me .

[@fdavillar]

Keeping up with this project is now part of my life.

[@ianbertenshaw4350]

All this time i have been setting up the eccentric in the drill press by eye to drill the hole for the set screw and i never ever thought of doing it like that ! Thanks for the video Joe and the fantastic tip !

[@johntenhave1]

That was very clever!.This project has been a wonderful teaching opportunity! near enough vs spot on is the difference between a professional and an amateur. Thank you for the continuing education.

[@Engineerd3d]

This day is saved. MrCrispin and Joe Pie video in one day? Yes please!

[@joepie221]

I enjoy Mr Crispin's work as well. he is a talented guy.

[@glenncerny8403]

I am really enjoying this project. Lots of good tips along with some good humor. Thanks.

[@snappers_antique_firearms]

I absolutely love this series it's been one of my favorite.

[@joepie221]

Thanks. I'm having fun.

[@goodboyringo9716]

Most professional machinist I found on youtube .

[@jackdelancey248]

The pin trick was helpful I will definitely use it in the future. Thanks 👍

[@bcbloc02]

I appreciated the order of operations to get this one done.

[@bigdawgsbusa2]

Same thing here Brian sometimes you can get backed in a corner and make things 10 times harder. The shop i help out in now for some more shop space I find them not thinking things through making thier jobs much harder

[@steelers19571]

are you a teacher if not you should be a lot of kids out there need someone like you

[@johnferguson2728]

Just my personal opinion, but I think Joe is one of the best teachers I’ve experienced!

[@joepie221]

@@johnferguson2728 Thanks John. I enjoy teaching and seeing the moment the lights go on.

[@2tana22]

I enjoyed this one, I’ve got to go back to collage to know what your were showing us

[@tsanger121]

Love this series Joe!!

[@jeffreylehn8803]

Great job Joe , I have used this fool proof method to make eccentrics for the past thirty years .Also it was refreshing to see that you ground a tool with the proper clearances to cut the groove too many "machinist " jump to a parting blade for this and it's simply not the way to go . The problem here is that most "machinist " don't know how to grind tools , I have worked with my share .

[@slawnski]

Great content Joe. I always pick up at a handful of useful tidbits from your videos. Much appreciated.

[@ghl3488]

Joe, it's like Christmas morning every time you put up a video. Thank you so much. Regards Gareth in Wales

[@joepie221]

Thanks. I'm glad you enjoy them.

[@jeffanderson1653]

Beautiful job. The finish is incredible. 12L14 is really soft, here they have brass and 12L14 (or equivalent) Once the model is run in, wear must not be a concern. Oil up! I was wondering how to set up to drill and tap . Thank you Joe, anyone building these models have a professional instructional video to refer to. You da man.

[@christopherwestphal6283]

That hurt my head a little when you used the pin to clock the set screw, but that made absolute sense! I like it!

[@TheKnacklersWorkshop]

Hi Joe, I did like the way you setup the part in the 4 jaw check… Take care Paul,,

[@jcollins310]

Loving these videos. Keep up the good work Joe.

[@Stefan_Boerjesson]

Well made would be a greate understatement. Lots to learn, lots to just enjoy and admire.

[@yt66228]

Once again I learned a new way to use the pins. Joe I usually make the strap a little tight and lap it in for a beautiful fit!

[@joepie221]

I'm looking forward to doing the strap and connecting rod.

[@gagasmancave8859]

Hi Joe, find myself having to make two eccentric s and went looking for a you tuber to teach and you are the man. Many thanks

[@stejac51]

.... Oh NICE .... just love watching you work .... logical ... concise ... ACCURATE !!

[@joepie221]

Thank you very much!

[@tonyking2030]

I’m learning so much from your videos. So well presented & very enjoyable to watch. A master of your craft!

[@lindabergquist4608]

Hi Joe, thanks for your video. I have made at least 5 of those cams and still you manage to help make me better at it! Please keep the videos coming Rich

[@joepie221]

Will do!

[@lastfrontier_vanscapes5694]

Great video thanks a lot Joe! I'm always learning something watching you

[@barryfields2964]

I’m watching another KZbin channel that is actually making this same engine right now. And they did the piston last video, or maybe 2 videos ago, and they had to kinda guesstimate at the rings. It’s real interesting watching two people make the same thing at the same time. And seeing the different techniques they use.

[@joepie221]

I just finished the piston and will post the video shortly. Subtle differences that enhance the accuracy of the part. Come back and take a look at how I approached it.

[@1962clarky]

Love watching your work Joe.

[@gordondowdy833]

Perfectionism at it's finest! You amaze me and I enjoy the time you spend on setting up for the job. I can't wait for the next portion of the build. Be safe!

[@joepie221]

Thank you very much!

[@johngunn7087]

Thanks, Joe. Excellent content, as usual !!

[@jameswilliams-tn2sf]

once again Joe its seem everything is come together with the engine and can't wait to see it working . and thanks for the video ,am learning a lot.

[@ChrisB257]

Another gem Joe, more magic - thanks as always. Much enjoyed.

[@brianjohnson217]

Hi Joe when I make an eccentric I've always carried out the whole procedure from start to finish in a 4 jaw independent chuck . Since watching yet another excellent video of yours , next time I'll start the initial procedure in the mill . So much easier and much more accurate. Many thanks for your excellent workshop videos. Best regards Brian

[@joepie221]

Thanks Brian.

[@Mystic0Dreamer]

Thanks for the bonus Oil Cup comparison at the end. I see It pays to share a comment on this channel. (Big Smile)

[@joepie221]

It was something I should have shown. It was a good suggestion.

[@zipedadoo]

One thing to mention. The prints for this model are all 1:1 scale except for these parts. They made the prints for these parts 2:1 I assume so the dimensions are clearer. Messed me up until I realized what was going on.

[@christurley391]

Thanks for the video Joe.

[@glenncpw]

Really common sense, but I am glad you explained it. Another truly great video on machining...

[@Tryin2FlyII]

I Luv Ya Joe !!!! lol You make things so clear and easy to understand you & mrpete and Abom79 are so helpful Thank You and God Bless and as always TWO THUMBS UP SIR!!!!

[@ettoredicarlo1679]

Great stuff Joe.

[@billbrennan8405]

Joe you are a thinking man’s man when it comes to machining. Always enjoy your videos, and your shop is like a trip to Disney Land of machines. Stay safe ‘ Happy Holidays. BB

[@joepie221]

Thanks. I enjoy being here. Happy Holidays to you as well.

[@ophirb25]

Great work, great tips and tricks. Thanks very much.

[@maciekwarszawa3776]

I can't wait for the next video. Best regards from Poland.

[@joepie221]

Thanks for the enthusiasm. I'm enjoying this too.

[@markfulmer8501]

Hi Joe- great video again . I always enjoy seeing different ways to do a job. The pin alignment idea is pretty slick and will be used. Keep the ideas a coming. thanks

[@AP9575-jd]

Nice way to find the two center lines Joe π Thanks

[@joepie221]

Pretty reliable method.

[@TomokosEnterprize]

I've been wondering what you have been up to. Time to refill my coffee, sit back and enjoy. Thanks Joe !

[@rtkville]

Another great video Joe, thank you!

[@Smart75]

About the tiny Oil Cup at the end, It literally says "Scale 2x" under the drawing itself. The saying should be "Read three times, measure twice, cut once".

[@chrisstephens6673]

It already is.

[@bigdawgsbusa2]

Great work Joe, I've been out of pocket so I have to go back and play catch up and the ending looks like that part was a treat.

[@joepie221]

Glad you enjoyed it

[@troydugstad4759]

Great video, lots of awesome little tricks!

[@alasdairhamilton1574]

19:40 Every tool has a hammer side, even in Joe’s shop😁🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@scottthornton9237]

Nothin is more fun than making tiny parts on a big Lathe! Add to the dilemma when the tolerances are smaller that the capabilities of the DRO.. Makes for many "ghost passes"! I was tasked with making a stainless bushing with a 0+ .0003 OD, 0 - .0003 ID the part was .300 OD x .200 thick. Made on a 10" 3 jaw x 10' lathe. Some how managed to make 2 with no losses.. Yes i know, just a baby bushing! Lots of sweating though! Not nearly as complex as that tiny oiler you made! EDIT: I typhoid 0.00003 meant 0.0003. Now corrected. Thanks for those who caught my error.

[@31415geon]

Wait, a tolerance of 30 millionths of an inch? How is that possible?

[@totensiebush]

You're sure you don't have an extra 0 there? I could see 3 tenths, not so much .3 tenths.

[@joepie221]

How did you measure that? Something that small would also need a climate controlled environment.

[@scottthornton9237]

@@totensiebush Yes! i have an extra 0 in there! I meant to type 3 tenths!

[@scottthornton9237]

@@31415geon I screwed up typing, I meant 3 tenths! not .3 Tenths.

[@metalshopwithtroy5755]

Another great video Joe thankyou for your contributions 👍👍👍😊

[@joepie221]

Glad you enjoyed it

[@GaryT1952]

Filing away the razor blade trick...thanks Joe

[@gregsmachineshop]

Joe, Thanks for the wonderful video. Everytime I watch your videos I pickup something new, even if I have watched them numerous times. For example, When I square up my tool to the work piece, I have always loosened the tool post instead of just moving the tool as you did. the problem with adjusting the tool post is, of course, the next tool I put in the tool post is out of alignment. Seems obvious now. Thanks.

[@joepie221]

Its nice to watch a part made, but I like to include things you can take away and build on. Thanks for the comment.

[@TrojanHorse1959]

Great video and explanations Joe, thank you!

[@highpwr]

Thoroughly enjoyed.

[@myoniwy]

@JoePieczynski Why did you mark the two red dots on the jaws of your lathe?

[@ehess1492]

I’m guessing he uses that to remind him which two jaws to open, and which two to not open when chucking multiple times.

[@wwilcox2726]

I'd like to hear Joe's answer to that question also.

[@Shop-Tech]

Or which jaws to not open. I'm interested in hearing the reply.

[@TheTacktishion]

Another job well done....!

[@jrcampbe]

Hey Joe, why do you need the shims in the 4 jaw? Why not just tighten right down on the stock?

[@wwilcox2726]

I was curious about that also.

[@davidmasters9793]

Maintain surface finish is why I would do it

[@milantrcka121]

Aluminum is a bit softer than the steel material. Under pressure the part will make an indent and will hold better with less force. Also as the jaw closes, the opposite shim will also compress to allow the part to "move" in the desired direction.

[@Shop-Tech]

I bet its because the part slides better.

[@herbhartman7528]

Awesome vid, really enjoy watching and learning from a great machinist!!

[@joepie221]

Glad you enjoyed it

[@timothyprochilo4840]

Thanks again Joe.😎

[@James-fs4rn]

👍 learned me something again. Thanks Joe.

[@tomcook5813]

Joseph, what are you using for cutting fluid? Being self taught I like Marvel Mystery oil with 10% clean deisel fuel. My issue is with aluminum, aluminum gets more gummy with my home brew fluid.

[@joepie221]

trim sol water soluble in my CNC and brushed on wd-40 for general lathe work. I used kerosene on aluminum for many years. Tapping is moly D or anchorlube for steel, tap magic for aluminum.

[@tomcook5813]

@@joepie221 Took notes, on the grocery list, thank you as always

[@lescotta7427]

It is very spooky that it made total sense to me on the concentric wow!!!!!!

[@leonmccarley5273]

Joe, at 16:43 I'm thinking you want to subtract .061 from .314, then divide resultant .253 in half to put the left edge of your tool at the center of the feature.Then .037 left to center the tool in the feature. First ever comment on the tube from old marine, gunsmith, QC guy. Love your channel.

[@joepie221]

Sooner or later, you will need to factor in the width of the tool regardless of the approach. My way, thats already done.

[@leonmccarley5273]

@@joepie221 Thanks Joe. My eyes told me that the tool would be too far to the left to allow for equal movement to each side, but the numbers prove you"re right.

[@outsidescrewball]

Lessons, lessons, lessons.....thank you

[@joepie221]

Good Morning Chuck. Thanks for stopping by.

[@David_Best]

Joe, question: at about 12:15 in the video, you cut the smaller OD eccentric feature using an insert tool I can’t identify, but would love to know what it is. The tool holder looks similar to a TopNotch, but the insert geometry suggests otherwise. The insert has what appears to be a 0° lead angle with the top edge doing the cutting. Please tell me what this tool is - I want one. And thanks as always for your excellent videos.

[@terrymoorecnc2500]

It's an old style TPG 322 with a chipbreaker on top. Got a box full of those inserts.

[@joepie221]

TPG 321 insert. Discontinued Kennametal holder. i think Iscar has them.

[@terrymoorecnc2500]

A bunch of the Kung Fu tool companies still make the holders without the chipbreaker.

[@David_Best]

@@terrymoorecnc2500 Kung Fu? Racist much?

[@David_Best]

@@joepie221 Thanks. I couldn't tell from the video that the insert was laying flat and triangle shaped. Now I see it. Kennametal still makes the holder. www.mscdirect.com/product/details/52982469

[@JaborWithaY]

Some interesting shutter speed effects here - the eccentric offset often makes it look like the part is going backwards on the lathe!

[@machinery6878]

Thanks, Joe. Much respect. Mating part is the eccentric strap?

[@joemiller5110]

Thanks Joe

[@bulletproofpepper2]

Thanks for sharing. Great video.

[@TomokosEnterprize]

I sure enjoy your nice easy approach to the tooling and depth of cut you use. It is like you really enjoy what you are doing eh. Others have mentioned the amount of adds you run. I am not fussy about any adds but they are a necessary evil so I do let a couple run as they are short and sweet along with making a penny or two for you.One day I may be able to monetise but they keep changing the rules making it harder to do so so I really don't care anymore. Really likin yer tips and tricks. The improvements in tooling and measuring have greatly improved over the last 47 years is amazing my friend. One day I would love to see a job done with a simple standard dial indicator. How about one of those my friend ?

[@CodonaProductions]

Beautiful work as always Joe. A quick question on aligning the eccentric center for the set screw, why use a gauge pin instead of a gauge block?

[@joepie221]

Either would work, its just faster for me to grab the exact size pin.

[@wwilcox2726]

If you work fast or have fumbly fingers, gage pins are much cheaper should you have a mishap. Gage blocks rely on preserving their extremely fine face finish to provide them the ability to be "wrung" together with other blocks to make non standard lengths, Eg. .161" etc. Gage pins are often sold in large sets like .061"-.250" in .001" increments which makes things easier. The exception would be if you need a pin diameter who's radius is greater than the length/height of the step/shoulder, then a gage pin won't work as you'd no longer be measuring across the full diameter of the pin. If you don't want a complete set of pins they can be purchased individually for about $2 each. :-)

[@perpetualnerd4388]

Can't wait for the next one.

[@denisrobillard5869]

Hi Joe, Thanks for the video series. Very clear and informative. I have watched this series twice now and I am now starting this model myself. Question: where did you get or how did you make the chamfering tool seen in the video at12:46? Thanks in advance and thanks again for the videos and the channel.

[@joepie221]

I made it many years ago. Originally for internal o'ring groove deburring, but found it very useful for OD and face chamfers as well.

[@denisrobillard5869]

@@joepie221 Thanks. I’ll be keeping a closer eye when you use it as I would like to make one. Looks like a piece of 1/2” round HSS?

[@joepie221]

5/8 with 1/2" flats. Carbide brazed to the front.

[@SlowEarl1]

Nice set up tips! Thank you!

[@joepie221]

Glad it was helpful!

[@westweld]

Joe your a gold mine......have you considered a book id buy it

[@ericsandberg3167]

Joe, I guess an alternate would be to sweep the smaller eccentric until you got the lowest height reading....I'll have to experiment with this and see what kind of tolerances I end up with.

[@joepie221]

The solid hit will be closer. the top of an arc has minimal drop during rotation.

[@kgee2111]

Looks great!

[@miltable]

Time stamp 4:14 "center drill". Why do you like it better? kzbin.info/www/bejne/haWbqIN9hrxmgKs From the CNC Cookbook: "A lot of machinists use center drills for spotting instead of true spotting drills. Center drills are intended to be used to create a hole suitable for a lathe center. They have a 2 part tip that has a small pilot as well as the larger countersinking area of the bit. While center drills are available more cheaply than spot drills, they have some disadvantages. The small pilot tip is very delicate for example, and if it breaks, the drill will quit cutting. Not a happy thing if you’re running a job that involves spotting a lot of holes. Another problem is the hole angle of a center drill is typically 60 degrees. When spotting, you want an angle that is larger than the twist drill’s angle if possible. The narrower the spot angle, the more near the outside diameter of the twist drill first contact will be. If the twist drill’s flutes aren’t perfectly sharpened, one will contact the spot hole before the other and the drill will try to deflect. This defeats the purpose of spot drilling and can result in a less accurate hole. The broader angle of a true spot drill means the tip of the twist drill cuts first, which makes for a more accurate hole. Lastly, the web of a spot drill is typically thinner than a center drill, so it cuts more easily and with less heat." Also see www.harveyperformance.com/in-the-loupe/choosing-spot-drill/ I hope you will answer this because I am really curious why you like center drills better than spotting drill especially in light of how drills cut as is explained here: kzbin.info/www/bejne/fXrRdIKZipqca7c Thanks

[@samrodian919]

Thank you Joe, I have learned a lot on this piece today! One question however, what is the reasoning for using shims in the 4 jaw when the piece was going to be parted off and the material left in the chuck is effectively scrap? Or is that material for another part and you didn't want to mar it up?

[@kgee2111]

Possibly so you can “feel” when the chuck jaw just makes contact?

[@wwilcox2726]

That's a great question, I hope Joe answers it. Several people have asked the same question.

[@janstaines5989]

Hi Joe, when chucking up the part in the 4 jaw, you said the rotational alignment isn’t important (I think). If a line was drawn through the centre of the off-centre hole and the centre of the stock, wouldn’t that have to line up with one pair of jaws? I guess what I’m asking is: should the offset be reasonably aligned within the path of a pair of jaws with the pair 90° to those being roughly equidistant from the centre? Thanks!

[@wwilcox2726]

If turning a rectangular or square part in the four jaw, having the centerline's line up would simplify jaw adjustments. In this demonstration Joe only needed to cut the OD for the shaft boss relative the the shaft hole centerline. He indicated the top side of the pin and made his jaw adjustments at 12:00 position.

[@janstaines5989]

@@wwilcox2726 thanks for the reply! I didn’t know if having the jaws side loaded was a good idea, or if it was better to have the loading for each jaw straight down its path of travel?

[@wwilcox2726]

@Jan Staines the advantage of a 4 jaw is to hold irregular shapes and so it's common to have some side loading of jaws. If the part heavily side loads a jaw you won't have a reliably rigid set up and shouldn't hog material with a set up like that.

[@janstaines5989]

@@wwilcox2726 thanks for the info! 👍

[@johnferguson2728]

Thanks again Joe. Another informative and very entertaining video. You make it look easy. I’d purchase this series if you offered it on a CD just to make sure that I’d always have access.

[@amicidavinci]

I'd second that...

[@Shop-Tech]

@@amicidavinci Third.

[@gvet47]

Why did you use shims on your 4 jaw but then did not on the 3 jaw? Would the 4 jaw not close down on the diameter you had? If you ended up having to dial the pin so the hole was on true axis and clock the offset then why not just drill it on the lathe? Mine is a lot smaller on a Stuart S50 and very small offset.

[@mchiodox69]

Awesome....but why did you use the shims on the 4-jaw?

[@rhysd5410]

Because he didn't want to chew up the outside of the stock with the chuck jaws.

[@mchiodox69]

@@rhysd5410 Why not use shims on the 3-jaw then?

[@wwilcox2726]

@@mchiodox69 that seems to be the million dollar question. Several of us posted the same question, but Joe has neglected to respond?

[@michaelwise1224]

@@wwilcox2726 Shims for the 3-jaw would be unequal thicknesses to obtain the eccentricity and would be a fiddlier set up.

[@mathewmolk2089]

@@rhysd5410 Who cares? Its the drop that's in the chuck. - Wish JP would respond to this 'cause I see no reason to do it.

[@tomweinstein]

The correct name is the eccentric sheave, and the enclosing part is the eccentric strap.

[@Shop-Tech]

Why does the drawing say differently?

[@johnhubbard3399]

Joe I hope you plan on running it :-)

[@Stefan_Boerjesson]

Thanks for a very enjoyable video. Have You ever thought about "stand up commedy" as a "product"? Time 03:00 Centering by eye balling the distance using the sencitive indicator instead of a 1" one... Nice to see You also using that technic. Time 07:00 Needing 19 hands.... Quite a bit more than the 10 armed octopussy. Maybe a centipede having the flexibility of a monkey? Time 09:00 Why the shims when You will part off the excenter? Time 10:00 Just what I felt cold be done, and then You did it. Time 27:45 Not exactly the tool in every shop I think. Timr 30:10 Ten hands.... That's a progress from 19 hands... Time 31:45 What a rigging, several loose pieces to align. Brrr. Calls for a master.

[@totensiebush]

I've mostly heard it called 12L14 rather than Ledloy, I hadn't heard the brand name before but expected it to be pretty much the same.

[@dreamsteam8272]

32:00 double check by doing the same on the other side (right an left) 😉😉😉

[@carlwillits9077]

Another great video.Thanks. Is the tap wrench at 33:25 commercially available or is it one that you made?

[@jeffanderson1653]

I bought the #5-40 tap from McMaster Carr

[@joepie221]

Hi Carl. I made it. It gives great feel for smaller taps. I may shoot a video on that. Many have asked that same question.

[@highpwr]

@@joepie221 I think by now a video from you on that tap handle is a moral imperative... . Probably be a hot seller in your web store also. Just sayin. ;-)

[@Shop-Tech]

@@highpwr I'm in.

[@ericsandberg3167]

Joe, I'll assume the set screw had to be clocked in that specific position for its interface to its mating part....if you were not able to use the .25" pin and get the eccentric lobe into alignment, what other technique could you use to make sure this set screw thread got aligned in the correct orientation.

[@casey2219]

use an indicator and sweep the high spot of the large diameter, then zero out your readout, and indicate the high spot of the smaller diameter. If the difference reads .250 then you are inline. If it doesn't read .250, adjust it and re-measure the difference. it will require more finesse but would be do able. also you could machine a blank that is .250 wide and use that as a replacement for the pin.

[@milantrcka121]

Actually you ultimately adjust the eccentric angular position for an early admission (within reason) to cushion the piston before TDC to keep the "float" loaded in one direction. This reduces/eliminates "clunk".

[@kgee2111]

You can also use a very small diameter pin suspended across the vise jaws and let the part “hang” evenly. Not super accurate but it will work.

[@joepie221]

@@kgee2111 That puts the set screw hole on the wrong side since the weight goes to the low side doing that.

[@joepie221]

@@casey2219 Radial error potential indicating the top of the eccentric hub could be much greater using an indicator. You may be surprised at the minimal drop an indicator would show you during peak rotation.

[@1crazypj]

'We' always called low carbon high lead steels just 'freecutting steel' in Britain. After seeing the oil cup video I made some small brass parts, 0.5mm hole 5mm deep was a lot easier than I expected (although I did have my face up against lexan guard with an x10 loupe to see what I was doing)

[@peterspain3827]

Hi Joe I have copied your process of making the eccentric brilliant.for anyone making this part i would recomend using the mill to offset the journal,so much easier.But why did you use shims in the chuck particularly. I clamped the part directly with the jaws and it worked fine.I messed up the position of the undercut by the way and had to go again but hey.Keep it up Joe great work.

[@joepie221]

I used the shims so any damage was to the shims and not the part.

[@Ujeb08]

as for the reason the designer chose a 5-40 thread ; I would guess that they wanted to be sure that there was an adequate amount of threads in the wall thickness of that boss (3 threads).

[@joepie221]

You may be right.

[@Ladamanmba]

Excellent video as always. I would be interested to see how you would tackle an accurate offset similar to this item but done purely in the lathe. I recall a method where the bore would be drilled and tapped and a button then bolted on and set accurately and used for a clocking datum in the lathe. Once set remove the button and drill and bore as required. Or do have you a better method?

[@joepie221]

Use a 4 jaw chuck and a drop indicator to set the offset for the hub and bore, then return it to concentric for the OD groove.

[@bhoiiii]

I’ve always heard that bottoming a reamer can cause an oversized hole. Is that a myth? Would love to hear from the experts on that one.

[@LaukkuBah]

Yeah, if the tailstock is off center. You still haven't heard from an expert though.

[@joepie221]

It would depend on the amount of force and the size of the reamer. Smaller diameter reamers can bow and that causes the oversize cut. If chips are uneven at the bottom of the hole and you compress them, that can make a reamer run out and cut oversize. Once I feel the chips packing up, I'll back it out. A 3/8 reamer is pretty stout.

[@bhoiiii]

@@joepie221 makes perfect sense. Thanks Joe.