Some Lathe Stuff

[Kevin54]

I just received a copy of The Home Shop Machinist magazine and the Tormach is in there with a price of a little over $8g's. That's not a bad price. Table movement is a little small though. But if you design a larger part with construction holes, you can do larger parts with no problems.

 

[Kevin54]

As far as using a mandrel to press in the bushing, if you are using a hand arbor press, and the shaft has any slop, you might get into trouble with a mandrel. If it starts to lean, then you will have the bushing going in crooked. Personally, I always use a flat ground block, like a 1-2-3 block to press in bushings. It gives your arbor press and you bushing a little more bearing surface to press the bushings in. It's a personal preference, and on some things I do use a mandrel, but I prefer a block. If you do use a mandrel, as Occupant stated, make it long. I like to set a 1-2-3 block down, then set a "V" block on top of that so you can get it against the mandrel to make sure it's straight. I can see something lean just a little bit, my wife will tell me something looks straight and it might be leaning 5 degrees. It never hurts to use something to double check yourself.

 

[OccupantRJ]

I actually have pressed a lot of smaller bushing in place by using a bench vise, with aluminum softjaws to protect the bushing from the vise knurls. Works well for a lot of things.

 

[deere2210]

Couple pics of the finished part.. Little embarrassed.. I ran the part and realized the four holes were supposed to be tapped for 1/4-20.. I used a .25 drill bit instead of a 13/64 Reran it again.. Anyway, gave me a chance to play with the boring bar some more and it went a lot faster this time.. I also milled out the countersync on the backside and added chamfers on both sides.. The additional pics are tonight milling out the brake lever arm... Spent some time facing everything to make sure they were flat.. Was quite a bit off before facing..

 

[z1wiz]

I can't tell by your picture, but is there another piece of aluminum under the one you are cutting? I usually keep some "sacrificial" plates of aluminum around just for this purpose. I'm jealous of your CNC as all my equipment is manual. I have to get creative with setups to make parts in my shop. Thanks for sharing your work.

 

[zkling]

AMAZING work Deere2210!!!!

I too am another SW Ohio guy.

There is only one problem I have with your setup.... Am I really seeing what I think I am seeing??? Is that................Open, clean, floorspace?

All joking aside, great work!

 

[Kevin54]

Couple pics of the finished part.. Little embarrassed.. I ran the part and realized the four holes were supposed to be tapped for 1/4-20.. I used a .25 drill bit instead of a 13/64 Reran it again.. Anyway, gave me a chance to play with the boring bar some more and it went a lot faster this time.. I also milled out the countersync on the backside and added chamfers on both sides.. The additional pics are tonight milling out the brake lever arm... Spent some time facing everything to make sure they were flat.. Was quite a bit off before facing..

You didn't have to scrap the first one. You could have just put HeliCoils in it and saved it. But then again, practice never hurts either.

I noticed you have cam clamps holding down the large plate. Do you like them? Do they seem to hold the plate fairly tight? The reason I ask is that we only just started using them at the shop in the last couple of years.

 

[OccupantRJ]

suggestions: chamfer edges of holes, includiing tapped holes, unless not desired. Use boosters of sacrificial material under the large plate to help insure you do not accidently mill into your table. I see that with the wrong drilling of the tapped holes that you are getting the REAL maching training that you will ultimately need. Learn to stop before engaging each step of an operation, to give your mind time to review what you are about to do, never remove a part from the machine before doing a step by step review of the operation you are on, think out the next step, and it will do wonders for you.

 

[deere2210]

I can't tell by your picture, but is there another piece of aluminum under the one you are cutting? I usually keep some "sacrificial" plates of aluminum around just for this purpose. I'm jealous of your CNC as all my equipment is manual. I have to get creative with setups to make parts in my shop. Thanks for sharing your work.

Yes, it's probably hard to tell. When I faced the parts I didn't have anything under the plate since I was just taking a facing cut. That's the pic without anything under it.. When I milled out the arm, it's actually another piece of scrap plate set on the bottom of the first and strap clamped.. It's hard to see with the coolant and swarf.. Setups/fixturing is an art within itself.. I find myself thinking about fixture design as much as the part..

 

[Kevin54]

Deere...these are the clamps I was asking you about. How do you like them for holding material down? Do they seem to work out for you with no problems? I've used them a few times on fixtures in the past, but never got to see them in use.

 

[deere2210]

AMAZING work Deere2210!!!!

I too am another SW Ohio guy.

There is only one problem I have with your setup.... Am I really seeing what I think I am seeing??? Is that................Open, clean, floorspace?

All joking aside, great work!

There are a few of us SW Ohio guys on here. Nice to meet you! Yes, I'm pretty diligent about sweeping and organization. Every tool goes back in the exact same place, no shelves on the wall (so I have full floor space), and everything on wheels so I can move around.. My wife is always griping the shop is cleaner than my spot in the house!

 

[deere2210]

Deere...these are the clamps I was asking you about. How do you like them for holding material down? Do they seem to work out for you with no problems? I've used them a few times on fixtures in the past, but never got to see them in use.

Kevin, I just got them and first time using them. They are Mitee Bite t-slot clamps. I will have to say they are fantastic.. They hold really well, quick lock down.. And, they are low profile so I can face the whole plate. They are going to be a core tool in my kit now. I looked around and there is a $30-$40 price difference for the same ones. I found them at Penn tool for $40 less than other places.. I highly recommend them!

 

[Kevin54]

Kevin, I just got them and first time using them. They are Mitee Bite t-slot clamps. I will have to say they are fantastic.. They hold really well, quick lock down.. And, they are low profile so I can face the whole plate. They are going to be a core tool in my kit now. I looked around and there is a $30-$40 price difference for the same ones. I found them at Penn tool for $40 less than other places.. I highly recommend them!

I don't know if you have ever purchased anything from Carr-Lane, but for 5/8" clamps in there, they run $22.50 ea. I may have to pick up 4 of them just to have on hand for doing what you used them for, facing off your material without using toe clamps.

 

[deere2210]

I don't know if you have ever purchased anything from Carr-Lane, but for 5/8" clamps in there, they run $22.50 ea. I may have to pick up 4 of them just to have on hand for doing what you used them for, facing off your material without using toe clamps.

I haven't heard of Carr-Lane but will check them out. I bought the clamps as a kit and got the four t-nuts and six of the camlocks, plus the allen wrenches/case.. I was surprised how easy they work and made facing so much easier than trying to work around the strap clamps.

This is the link to the kit: http://www.penntoolco.com/catalog/products/products.cfm?categoryID=322

 

[deere2210]

suggestions: chamfer edges of holes, includiing tapped holes, unless not desired. Use boosters of sacrificial material under the large plate to help insure you do not accidently mill into your table. I see that with the wrong drilling of the tapped holes that you are getting the REAL maching training that you will ultimately need. Learn to stop before engaging each step of an operation, to give your mind time to review what you are about to do, never remove a part from the machine before doing a step by step review of the operation you are on, think out the next step, and it will do wonders for you.

Occupant, see post #169 I just updated.. I had a picture of the facing op with nothing under it, but when I milled the lever arm, I had another piece of scrap that I had faced underneath it. Definitely worry about drilling into table. I now have a notebook/pen sitting next to both the mill/lathe like a pre-flight checklist to check everything before/after. Didn't break down the fixture plate as I plan to go back tonight and rebolt it back down and finish bore since the other end of the bushing need to go into this piece also.

 

[Kevin54]

Here is Carr-Lanes address http://www.carrlane.com/catalog/index.cfm We used them quite a bit at work for our fixturing needs. One thing I like about them is that you can download drawings of most of there items. Very handy when designing tooling.

 

[OccupantRJ]

Occupant, see post #169 I just updated.. I had a picture of the facing op with nothing under it, but when I milled the lever arm, I had another piece of scrap that I had faced underneath it. Definitely worry about drilling into table. I now have a notebook/pen sitting next to both the mill/lathe like a pre-flight checklist to check everything before/after. Didn't break down the fixture plate as I plan to go back tonight and rebolt it back down and finish bore since the other end of the bushing need to go into this piece also.

I would slip fit the bushing through that piece, to make things easier for assembly.

 

[hunter1151]

I would just say this about the mitee bite set up you had for flycutting the plate. Only putting the clamps on the end of the part you run the risk of the middle of your plate raring up on you. Typical flycutters are positive rake cutters and will tend to lift the part if you don't have it clamped down. I would have put some other clamps near the middle of the plate to keep it flat. The only problems with mitee bites is that they only go in the t-slots and you have to shim them to reach, a lot of the times. I have used mitee bite products extensively and they do their job very well. Going to their site will open up a whole new clamping world for your mind. (I didn't mean mitee bites can only be used in the t-slots, but typically that is what people do) On our mills we have a drilled aluminum sub plate that we use to quickly mount about anything you can think of. It has a 2" 1/2-13 grid on it with 1/2" drilled and reamed holes for dowel pins. It makes clamping of vises and other shop aids immediate and in the same place everytime. I will try to post some pictures.

 

[deere2210]

I would slip fit the bushing through that piece, to make things easier for assembly.

Wow, that will make things a lot easier. I was worried about trying to get them both through straight. How much over is considered a slip fit? The bushing measures 1.003.

 

[OccupantRJ]

Wow, that will make things a lot easier. I was worried about trying to get them both through straight. How much over is considered a slip fit? The bushing measures 1.003.

Now is when you get to go back to that 1.005 diameter you wanted to get a chance to use.

 

[OccupantRJ]

Here you go. Look at shaft-hole classes of fit.

http://www.engineersedge.com/tolerance_chart.htm

 

[deere2210]

Couple quick ones of part I ran tonight plus a mock up of it starting to come together. Family is after me for family time tonight so will be back at it tomorrow..

 

[deere2210]

Made the cap that goes on the outside today.. I didn't have an insert or toolholder for the lathe with the right geometry to do the countersync so faced and drilled it on the lathe, took it over to the mill indicated it and then did the countersync, and then back to the lathe to turn the radius and part it off.. Little bit of work, however every time I simulated it in CAM the tool I was using crashed because of clearance.. So a little extra time/steps but it worked out..

 

[OccupantRJ]

We gotta get you dialed in on the basics. You're gonna work yourself to death. A drilled hole followed by a countersink of the proper angle would have gotten it all done in the lathe easily. An old school hand ground tool bit would also cut the countersink by setting the compound on the proper angle, then advancing the tool bit with the compound lead screw.

 

[deere2210]

We gotta get you dialed in on the basics. You're gonna work yourself to death. A drilled hole followed by a countersink of the proper angle would have gotten it all done in the lathe easily. An old school hand ground tool bit would also cut the countersink by setting the compound on the proper angle, then advancing the tool bit with the compound lead screw.

I don't have a countersync big enough to drill it so figured I could just do it on the mill. Grinding custom toolbit would have worked, but it was pretty easy to just put it in the vise on the mill and and push go. I already had the g-code written from the other ops so just reused.

 

[OccupantRJ]

I don't have a countersync big enough to drill it so figured I could just do it on the mill. Grinding custom toolbit would have worked, but it was pretty easy to just put it in the vise on the mill and and push go. I already had the g-code written from the other ops so just reused.

Well, that makes sense in your case. Sometimes I wish I could just push "GO" for a LOT of things.

 

[Kevin54]

I don't have a countersync big enough to drill it so figured I could just do it on the mill. Grinding custom toolbit would have worked, but it was pretty easy to just put it in the vise on the mill and and push go. I already had the g-code written from the other ops so just reused.

If you are going to be using a lot of flathead allen bolts, pic up a set of 82 degree countersinks. You can pic up a set relatively cheap. An 8 piece set from Penn Tool is $69. Enco is probably cheaper than that. With the 6 flute set, when you take it down to where it is on the straight part of the flutes, it gives you the depth of the flat that matches the head of the flatheaded screw.

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=7287

 

[deere2210]

If you are going to be using a lot of flathead allen bolts, pic up a set of 82 degree countersinks. You can pic up a set relatively cheap. An 8 piece set from Penn Tool is $69. Enco is probably cheaper than that. With the 6 flute set, when you take it down to where it is on the straight part of the flutes, it gives you the depth of the flat that matches the head of the flatheaded screw.

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=7287

Kevin, thanks! I'll check the link out.. I'll add them to the future purchase tools list.. That list never seems to get smaller but bigger..

 

[deere2210]

Hey, what do you guys have for recommendations on the below? First question is use of silicone washer? The .75 bar that goes through the bushing is .062 longer than the bushingto provide rotation. Some of the different plans I have seen called for a silicone washer.. I'm assuming for vibration dampening? I looked at McMaster and they have silicone bronze and nitrile.. I could cut my own out with the laser if it's just something like nitrile, but what kind of material should I be using??

Second question, was trying to figure out torque settings for the bolt that goes through the backplate into the bar.. The way it sits now, I will have 1 to 1.25 thread depth in the bar. The bolts are 3/8-16 316SS.. Is there a reference manual for torque I should tighten these to?

 

[Kevin54]

Deere....here are some torque specs from the engineering handbook http://engineershandbook.com/Tables/torque3.htm It should come up on the page for SST.

As far as the washer, any silicone washers that I have saw are soft and flexible. I would think you would want something with a little more rigidity. I believe what they are trying to do in this design, or what you are trying to do is have a washer, but allow it to compress so you still have pivot action. The two parts are going to be bolted together so the parts will be a rigid mount, the washer, is probably to keep the part from moving side to side. If I remember correctly, there was quite a bit of difference in size of diameters between the shaft and the bushing. Without going back through the pages, it was something like .010 clearance. I think if it were me, I would forget the silicone and go with something like a Teflon washer or a Delrin washer. Both will give you the slippage that you want. You just want to make the washer a couple of thou thinner that your total stackup so you still have free movement without binding, but enough that it will not let the part slide back and forth through the bushing.

And also, the four screws coming out between the parts, I imagine it is just the drawing showing the hole, but if the screws are actually coming through that far, trim them back a thread or two.

Looking at the drawing again, one other thing comes to mind....does the washer only have a 3.8" hole in it for the bolt to pass through? And if it does, that means thae washer is sitting on top of the pin coming through the bushing. It doesn't make any sense to do that. I was thinking the bushing went around the pin diameter. It would make more sense if it did, but if the bushing is on top of the pin it serves no useful purpose no matter what it's made out of. And if that's the case, I would probably eliminate the washer altogether.

If this is going on your bike, you may want to look into some Threadlocker. Maybe Blue Loctite so your screws won't vibrate loose. I wouldn't use any red, or it would take heat to ever back them out. And with using Stainless Steel screws, make sure that you use a good Allen Wrench or a new Allen Wrench. Stainless is a little softer and if you use a wrench that is worn a little, you'll damage the socket portion of the Flat Head screw.

 

[red92s]

If this is going on your bike, you may want to look into some Threadlocker. Maybe Blue Loctite so your screws won't vibrate loose.

Loctite does not do nearly as well on "inactive" materials like stainless or plated parts. The newer 243 (blue) and 263 (red) formulations of are better, but still fall well short of steel/steel interfaces in terms of cure strength.

 

[deere2210]

Yes, I think Delrin or Nylon might be better.. I ordered a small sheet of .062 of each from Enco today so can take a look and see how they work. I also changed the drawing.. The washer was supposed to have a .625 instead of .375 I.D. And, I extended the pin in the drawing .02 past the washer so it didn't bind.. And, good catch on the bolts.. I didn't catch that when I assembled it so reworking those also. Updated pic below which I think fixes it..

 

[deere2210]

Started making the brake peg and foot peg.. Was going to make it out of brass, but I found out brass is quite expensive..

 

[Kevin54]

Nice!! I haven't tried knurling on my lathe yet. I'm kind of curious to see how Chinese Knurls work.

 

[hunter1151]

Kevin...et-al, you do know there is a formula for knurling so that you don't double track. It is based on the knurls you use. Diameters must be held real close. Just giving you a heads up. Makes a differnce if you are using form knurles or cut knurls as well.

 

[deere2210]

Kevin...et-al, you do know there is a formula for knurling so that you don't double track. It is based on the knurls you use. Diameters must be held real close. Just giving you a heads up. Makes a differnce if you are using form knurles or cut knurls as well.

Not aware of the formula.. can you post? I ran these at 100SFM and hand fed it.. Diameter is 1.5 I'm using one of the accu-trak bump knurlers..

 

[deere2210]

Nice!! I haven't tried knurling on my lathe yet. I'm kind of curious to see how Chinese Knurls work.

Thanks! I used a small Chinese knurler on my previous lathe that came with it.. I didn't have a coolant setup and ran into problems with the pins on the knurler seizing.. I haven't done a lot of knurling so I'm guessing a large portion was operator influenced..

 

[sanddan]

Could you explain how you did the curved area at the end of the peg?

 

[hunter1151]

I'm not at work so here you go:
http://www.proshoppublishing.com/articles_knurling.html

 

[deere2210]

Could you explain how you did the curved area at the end of the peg?

I do a Groove Rough & Finish Operation and use an Iscar groove tool that can also be used to turn/profile.. You can see the tool in the pic below. Works really well.