Lever Action Clamping Screws

[Paul Jones]

Yes, I went hog wild on what started out as just two simple clamping screws for mini lathe change gear cover. It was so easy to make these that I started looking around the shop and thought about adding the levers for the next set. That led to making the improved slotting saw arbor for the Unimat, then the slotting fixtures, and then more clamping screws, and I am not done yet.

I used your knurling calculator to double check my calculations. I keep several spiral bound notebooks with green colored grid paper in my shop for my notes and pencil hand drawings. I keep a set of notes for knurl diameters that work well so I don't have to recalculate. I use an import scissor knurling tool from Enco that I have "improved". I would change the knurls to a finer knurl pitch if I could get the bearing pins out. Any suggestions from the readers would be appreciated.

All the brass tips are press fits and secured with Loctite 680 for good measure. In this case I used a 0.124" reamer X 0.30" deep in the screw tips before parting-off the completed part in the lathe. In case I forget this step, I can use a special chuck with the toolmaker mini jaws to hold the screws ( Homemade Mini Toolmaker's Jaws ). Probably the most important dimension is the OD of the brass tip so it doesn't mushroom into the bottom of the holes. I make these 0.05" smaller in diameter than the minor thread diameter. The Loctite helps in retaining the tip. Like in the oil drilling business, never want to loose a tool down the hole.

The Boeshield is expensive but the can lasts forever. I used Boeshield this time because when I removed the two clamping screws from the mini lathe for the group photo, I noticed the exposed tops were starting to rust as compared to the original photo taken a month earlier. I think it is because of the degreaser. I use Zep 505 spray degreaser on a rag to remove the lubrication oil from the oily knurled parts while the parts are still in the lathe. I want to see the knurls and determine if I need a second pass. I find that first lightly hand tightening the scissor knurling tool to verify the knurl tracks are tracking, and then using a wrench to further tighten another one-third turn usually produces a very clean knurl in one pass.

PJs thanks for asking,

Regards, Paul Jones

[PJs]

Thanks for all the info Paul! It's fun and frustrating to have to make a tool to make a part or another tool but do get the "I'm on a role now" feeling...fun!! I ran out of my small bottle of 680 a year or so ago but still have a big bottle of 603. Definitely a bit stronger in shear and better gap fill. Wish I had a set of reamers!! Good point on being under the minor by a skosh for the tips. Saw those tool maker jaws a while back and Really like them...been on my long list of todo's since.

Not sure of any method to get those pins out other than a press. Also check that both ends are the same diameter...seen some that have a slightly larger shoulder on one side that presses in (directional). Might try a heat gun for a few minutes and then use a pin punch and ball peen? On my inexpensive LMS one I use E-clips and made some new pins from O1 and hardened...much better than the originals...no galling yet either! Your Enco's have a lot more spizeringtom than the LMS with their finer thread and cone...would be great to do a single pass knurl! Thanks! ~PJ

[jere]

While most of this conversation is above my pay grade, pjs said it. Heat gun (or propane) to defeat the loctite then use a punch and a ball pein. Acetone and vegetable oil 50/50 makes a good penatrating oil to use with heat, when dealing with rust and thread lock too.

[Paul Jones]

jere,

Thank you for the advice for freeing the pins used to hold the knurls. I will definitely try the homemade penetrating oil. I remember seeing many comments about the benefits of this type of formula on HomemadeTools at http://www.homemadetools.net/forum/h...rating-oil-159 . Looks like a real winner.

Thanks, Paul

[aphilipmarcou]

Nice job. What kind of knurler did you use ?

[Paul Jones]

Hi Aphilipmarcou,

Thank you for the compliment. I use an import scissor-type clamp-on knurling tool that bought from Enco years ago and have modified and improved it by removing all the "slop" out of the tool. I also added a feature that makes it easier to tighten the knurling tool by hand and most of the time do not need to use a wrench to tighten the knurling tool (see http://www.homemadetools.net/forum/k...7860#post24656 ). Using the feel by hand makes for more consistent knurling when using around 150 to 240 RPM and a feed rate of 0.008" IPR and plenty of lubrication (not cutting) oil when working with 303 stainless steel. It usually takes two passes, one to the left and a return to the right to produce a sharp knurl.

A good example is some of the kitchen tools I made (see http://www.homemadetools.net/forum/s...3072#post77395 ). I also use a brass brush along the top knurling wheel to remove any flakes of steel that sometimes come off from the knurling process and this prevents the flakes from being embedded back into the surface finish. I always pre-machine the part diameters to the correct diameter dimension by calculating this by hand or using the Android phone app "Knurling Calculator" and typically make the part 0.001" to 0.002" larger than the suggested diameter. It is better to be slightly larger on the diameter than smaller.

I hope this helps to explain the knurling process I use on steels. The most difficult knurling for me is when working with brass and the best advice is to use a flood coolant or a Noga Cool Mist system to quickly remove the brass flakes produced when knurling brass.

Regards,

Paul Jones

[aphilipmarcou]

Hi Aphilipmarcou,

Thank you for the compliment. I use an import scissor-type clamp-on knurling tool that bought from Enco years ago and have modified and improved it by removing all the "slop" out of the tool. I also added a feature that makes it easier to tighten the knurling tool by hand and most of the time do not need to use a wrench to tighten the knurling tool (see http://www.homemadetools.net/forum/k...7860#post24656 ). Using the feel by hand makes for more consistent knurling when using around 150 to 240 RPM and a feed rate of 0.008" IPR and plenty of lubrication (not cutting) oil when working with 303 stainless steel. It usually takes two passes, one to the left and a return to the right to produce a sharp knurl.

A good example is some of the kitchen tools I made (see http://www.homemadetools.net/forum/s...3072#post77395 ). I also use a brass brush along the top knurling wheel to remove any flakes of steel that sometimes come off from the knurling process and this prevents the flakes from being embedded back into the surface finish. I always pre-machine the part diameters to the correct diameter dimension by calculating this by hand or using the Android phone app "Knurling Calculator" and typically make the part 0.001" to 0.002" larger than the suggested diameter. It is better to be slightly larger on the diameter than smaller.

I hope this helps to explain the knurling process I use on steels. The most difficult knurling for me is when working with brass and the best advice is to use a flood coolant or a Noga Cool Mist system to quickly remove the brass flakes produced when knurling brass.

Regards,

Paul Jones

Many thanks for A LOT of useful information there, Paul.