Molded stems still need to have their tenons turned

[Tano]

I just received an order of molded stems from Pimo, and found that there is no consistency in the size of their tenons, and they are rough. The tenons are all different shapes, so now I need to turn them to fit my desired mortise size. Problem is that, I only have a Pimo turning tool, and it will fit only in a 1/8" hole. That means I have to enlarge the existing holes in the stem to fit the Pimo tool. I see many possibilities for things to go wrong. I thought it would be simple, buy premade stems, and worry only about carving the briar. the best is yet to come... before I even layed a hand and experimented with one stem I went and bid on 50 more on Ebay. WHAT HAVE I DONE? How many of you use molded stems and is there a simple process? Is it wise to remove their tenons and replace it with Delrin? Help!!!

[bscofield]

I just received an order of molded stems from Pimo, and found that there is no consistency in the size of their tenons, and they are rough. The tenons are all different shapes, so now I need to turn them to fit my desired mortise size. Problem is that, I only have a Pimo turning tool, and it will fit only in a 1/8" hole. That means I have to enlarge the existing holes in the stem to fit the Pimo tool. I see many possibilities for things to go wrong. I thought it would be simple, buy premade stems, and worry only about carving the briar. the best is yet to come... before I even layed a hand and experimented with one stem I went and bid on 50 more on Ebay. WHAT HAVE I DONE? How many of you use molded stems and is there a simple process? Is it wise to remove their tenons and replace it with Delrin? Help!!!

If you remove their tenons (or that fat chubby part at the end of the pre-molded stem) and use delrin you will have to be chiefly concerned about an accurate drilling into the stem and the wood. Pimo stems do need to be drilled out to fit their cutting too. JHLowe stems do not, however (at least not the sizes I have gotten from him). I've turned those on the Pimo tool numerous times and it works out fine. If you end up drilling out what you have from PIMO to use their tenon cutter, then make sure you go real slow and pull out the bit often. If you go to fast the heat in the airway will scortch the stem. Make sure that whatever method you use to drill out the airway (drill press or lathe) is very stable. if you have a bad airway and are trying to use the pimo tenon cutter you can end up with tenons that become very hard to deal with!

[ScoJo]

I'll second the "go slow" part when drilling the stem out. Go a little bit at a time and pull out the let the shavings clear out. I spent a long time putting a wood inlay on one of those buggers, then realized I forgot to dril it out first. I went to fast and the damn thing split in half...

[bscofield]

I'll second the "go slow" part when drilling the stem out. Go a little bit at a time and pull out the let the shavings clear out. I spent a long time putting a wood inlay on one of those buggers, then realized I forgot to dril it out first. I went to fast and the damn thing split in half...

That would be especially bad because not only does the stem scorch on the inside but it also bulges on the outside...

[flix]

Tano,

The 1/8" hole you put in the Pimo stems may not even be enough: you then you need to also drill them out again at the final diameter. I drill at 5/32" anyway. There is some controversy about the hole size, but you need to keep the draw hole consistent throughout the stem, either 1/8", 5/32" or whatever you decide to use. Some people use 1/8" as the hole so you can keep it simple that way if you choose. I'd rather have a slightly larger hole to optimize draw.

I've used the Pimo Tenon tool several times now and it's a crude but effective tool. I use a battery operated drill and hold the pipe with my hand, it takes a couple of seconds. Not a big deal, really. Keep a tight grip on the stem though!

[KurtHuhn]

molded stems aren't too bad to deal with. The Pimo tool is actually made to cut the tenon on a pre-molded stem - hence the guide pin. No matter where you get them from, molded stems (also known as "pre-made" or "factory" stems) will need at least some modification. Tenons need cut, airwasy need cleared, and bits and buttons need tidied up. That's becasue the molding process isn't accurate, so you won't be able to get a consistent tenon size. Also, the factories recognize that pipe makers use different tenon sizes, so they just make a big tenon, and let the maker/factory/whatever turn them to the right size for them.

If you have a metal lathe, cutting a new tenon isn't as easy as cutting a tenon on rod stock, but it's nearly as easy. On a wood lathe, removing the tenon and replacing it with delrin is trivial.

[hazmat]

Kurt... cutting a tenon on the metal lathe I'm using isn't bad at all, just time consuming...er.. and that little exploding stem thing gets in the way sometimes.

However.. I'm still going to work with delrin if it serves my purposes. Anything that won't take away from the smoking goodness of the pipe but lessens the time and frustration it takes to turn a good tenon is worth getting used to. I figure the difficulties in getting the right bits for your mortises is nothing compared to cutting tenons "the old fashioned way"..

[Tano]

Thank you all , your comments are reasuring. However, never having worked with molded stems before, I still get the feeling that I'll be walking through a mine field for the time being.

[Hogi]

Well, my shop machne listlooks like this:
1. Electric drill
2. er, that's it...

Here's what I did with the pre-made stems.

Take a file. Place it in your hand so it lays in your palm. Put the tenon on it with your left hand, and scrape it up and down the file, turning the setem as you do so. Do this for a long time. Make sure you are not caving it into a cone, or it will split the shank of your pipe. It takes a long time and doesn't fit well, but it will work.

Good luck!

[LexKY_Pipe]

I have a JH Lowe tenon turning tool for sale. See the items for sale on this forum.