# DIY tramming device from MadModder forum ...



## wquiles (Dec 12, 2009)

link to madmodder forum - Milling machine tram tool

Very neat. However, since there is always more than one way to skin a cat: On the last step to true the base to the holding shaft; he faced the face plate, then attached the base and shaft to the face plate, then trued the shaft on the lathe. Couldn't that be done in reverse? In other words, couldn't you hold the shaft on the chuck and then true the face of the base on the lathe as it rotates (true, it would be an interrupted cut)? Wouldn't that yield the same level of accuracy/alignment with less work/setup/time?

Will


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## gadget_lover (Dec 12, 2009)

If he had used a press fit for the shaft instead of a loose fit, it would have been less likely to need any cleanup. Using a chamfered shoulder and a screw from the bottom made the alighment of the screw and shoulder the critical parts.

But I had a similar thought. Holding it by the shaft in a good quality collet or chuck would do the job. You just have to beware of flex and whipping.

Daniel


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## wquiles (Dec 12, 2009)

gadget_lover said:


> If he had used a press fit for the shaft instead of a loose fit, it would have been less likely to need any cleanup. Using a chamfered shoulder and a screw from the bottom made the alighment of the screw and shoulder the critical parts.


So you would have done a press fit of the shaft to the hole, and still use the bolt on the bottom, right? 

The bolt would only be there to keep the shaft from backing out, and one could still use high-strength thread-locker compound to make sure the screw would not turn itself loose, therefore achieving the same end goal of the original posted, right?

I like the overall project/idea, and I think it would be great to make one - of course we get back to the "problem" of finding time to do these projects


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## gadget_lover (Dec 12, 2009)

Yeah, it does sound useful. The surfacing on the lathe is the part that makes it work. That and finding a surface plate to align the DTI tips.

I think that the Loctite is there to prevent rotation more than anything else. It would be natural to rotate the device by grabbing the cross-bar instead of the spindle, pulley, etc. If the shaft rotates it will magnify whatever errors there are in the bore+shaft, since the shaft was turned to correct for those errors. So loctite on the shaft and the lightweight loctite on the screw in the bottom.

Daniel


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## precisionworks (Dec 13, 2009)

Dual indicator tramming tools have been around for a while, but all depend on the central shaft being secured in a chuck or collet - which will always introduce some additional error. Clamping an Indicol holder to the spindle removes that source of error, but does require looking at the indicator as it faces the "back" of its swing.

A better approach, IMO, is the Blake Co-Ax indicator. It isn't a replacement for the Indicol + dial test indicator, but it can be a life saver for some set ups. Blake makes the original & best version, and there are lots of not so well built knock offs. 

http://www.blakemanufacturing.com/pages/aboutus.html


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## niner (Dec 21, 2009)

I got this SPI mill tramming device from eBay. Bpth indicators wer broken, probably dropped. I replaced them and it works really well. Do I have to have it? No. But it does make tramming very easy to do.


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